The Developmental Precursors of Blunted Cardiovascular Responses to Stress

Abstract

Blunted cardiovascular responses to stress have been associated with both mental and physical health concerns. This multi-method, longitudinal study examined the role of chronic social-developmental stress from adolescence onward as a precursor to these blunted stress responses. Using a diverse community sample of 184 adolescents followed from age 13 to 29 along with friends and romantic partners, this study found that high levels of parental psychological control at age 13 directly predicted a blunted heart rate response and indirectly predicted blunted respiratory sinus arrhythmia (RSA) reactivity under stress. Heart rate effects were mediated via indicators of a developing passive response style, including observational measures of withdrawal during conflict with friends and romantic partners, social disengagement, and coping with stressors by using denial. RSA effects were mediated via withdrawal during conflict with romantic partners and coping by using denial. The current findings are interpreted as suggesting a mechanism by which a key social/developmental stressor in adolescence may alter relational and ultimately physiological patterns of stress responding into adulthood.

Recent evidence has shown that a blunted heart rate response to stress is linked to poorer psychosocial factors, such as trait anxiety, neuroticism, depression, bulimia, alcohol dependence, obesity, and greater life stress (Bibbey, Carroll, Roseboom, Phillips, & de Rooij, 2013; Koo-Loeb, Pedersen, & Girdler, 1998; Lovallo, 2013; Lovallo, Dickensheets, Myers, Thomas, & Nixon, 2000; Singh & Shen, 2013; Souza et al., 2015). Blunted heart rate reactivity has also been linked prospectively to poorer health outcomes, such as a risk of obesity, depression and anxiety, poor lung function, poor cognitive function, poorer self-reported health, and death from cardiac events (Carroll, Phillips, & Lovallo, 2012; de Rooij, 2013; Phillips, 2011; Phillips, Ginty, & Hughes, 2013). Similarly, blunted respiratory sinus arrhythmia withdrawal under stress (lower reactivity in the variation in heart rate that occurs during each breathing cycle), has been associated with problematic mental health indicators, and is often considered to represent difficulty appropriately responding to challenges in the environment (Lipschutz, Gray, Weems, & Scheeringa, 2017; Porges, 2007). Identifying the early precursors of blunted cardiovascular responses may be a critical step in mitigating serious health and early mortality outcomes.

Chronic stress in general appears to be a major precursor to blunted cardiovascular responses. Chronic stress, including mental health problems and exposure to childhood maltreatment (i.e., a history of involvement with child protective services), has been associated with the blunting of several biological responses, including cortisol, heart rate reactivity, and heart rate (de Rooij, 2013; Gorman & Sloan, 2000; Jansen et al., 1998; MacMillan et al., 2009). For example, in one study, adults who retrospectively reported experiencing significant adverse life events in childhood displayed a blunted heart rate and cortisol response to a stressful task (Lovallo, Farag, Sorocco, Cohoon, & Vincent, 2012). Blunted heart rate reactivity (which may be driven by sympathetic and/or parasympathetic control; Cribbet, Smith, Uchino, Baucom, & Nealey-Moore, 2020) appears likely to stem from exposure to chronic stress via two mechanisms: in part as a result of a reduced physiological capacity to respond to stress; and in part as a result of elevated competing responses elsewhere in the body, such as changes in total peripheral resistance (the resistance of arteries to blood flow; de Rooij, 2013; Phillips et al., 2013). RSA withdrawal under stress reflects reduced parasympathetic activity and helps prepare the body for mobilization (Porges, 2007). Though the literature is not consistent, exposure to chronic stress (e.g., adverse childhood experiences) has been associated with blunted RSA reactivity and this pattern is thought to stem from deficits in executive functioning and emotion regulation (Hamilton & Alloy, 2016; Oosterman, Schuengel, Forrer, & De Moor, 2019). Blunted cardiovascular functioning fits into McEwen’s (2007) framework of allostatic load, which he defines as “… the wear and tear that results from either too much stress or from inefficient management of allostasis…” (p. 880). In this case, chronic stress is likely contributing to the body’s difficulty in appropriately responding to challenges in the environment.

Although we know that stress in general is associated with blunted cardiovascular functioning, to fully understand and ultimately be in a position to address this link there is a need to identify the specific, key stressors in development that are implicated. This study examines whether interference with a fundamental developmental need— that of establishing autonomy vis à vis parents in the adolescent period—sets in motion a major source of psychosocial stress across the lifespan that could lead to blunted physiological responding. Adolescence is considered a sensitive period of psychosocial development, and stressors during this time are likely to reverberate into adulthood (Blakemore & Mills, 2014; Steinberg, 2005). Establishing autonomy is a central task of adolescence, widely recognized to be critical to development during this period with potentially longer-term implications (Allen, Hauser, & Borman-Spurrell, 1996; Allen, Hauser, Eickholt, Bell, & O'Connor, 1994). Individuals who begin adolescence with serious intrusions on their autonomy are likely to be set upon a maladaptive path that is stressful and taxing. In particular, early intrusions by parents on the adolescents’ autonomy strivings are both a source of chronic stress and likely to set adolescents on a path of passivity and withdrawal. Problematic parenting appears likely to work through these pathways to contribute to blunted cardiovascular responding in adulthood, as outlined below.

Psychological control has been identified as a major autonomy-undermining parenting practice involving intrusive and manipulative parental behaviors that violate boundaries between the child and parent (Barber & Harmon, 2002). Parents engaging in psychological control use strategies such as invalidation of feelings, guilt induction, and conditional acceptance to gain children’s compliance (Silk, Morris, Kanaya, & Steinberg, 2003). Greater psychological control by parents has been linked to various negative outcomes for youth, including internalizing and externalizing symptoms, lower academic achievement, risky sexual behavior, and lower self-esteem (Barber, 1996; Barber & Harmon, 2002; Bean, Bush, McKenry, & Wilson, 2003; Oudekerk et al., 2014). Parental psychological control in adolescence is especially likely to be problematic, as the need for autonomy becomes increasingly crucial for healthy development during this period (Deci & Ryan, 2008; Schleider, Vélez, Krause, & Gillham, 2014).

More importantly, a growing body of research suggests that a passive intra- or interpersonal response pattern fostered by psychologically controlling parents can have physiological effects into adulthood (Kopp & Réthelyi, 2004). Adolescents whose parents are psychologically controlling have been shown to develop an incurious, submissive style of responding (Barber & Harmon, 2002). After repeated experiences of autonomy-undermining behaviors from parents, they are likely to develop external passivity in the face of potential conflict (Hare, Szwedo, Schad, & Allen, 2015). They may develop low expectations of their own capacity to establish autonomy in social relationships, leading them to cope with potential conflict or stress by “shutting down.” This notion is consistent with research in childhood linking intrusive and insensitive maternal behavior to later social withdrawal (Booth-LaForce & Oxford, 2008) and is a pathway that also appears likely to alter physiological responding (Heleniak, McLaughlin, Ormel, & Riese, 2016). Withdrawn individuals are also likely to form relationships with similarly withdrawn partners, reinforcing these maladaptive interpersonal styles (Collins, Cooper, Albino, & Allard, 2002; McPherson, Smith-Lovin, & Cook, 2001; Stanley, Markman, & Whitton, 2002).

Adolescents who experience psychological control are also likely to develop more passive ways of coping emotionally, resorting to denying the existence of problems and disengaging, after learning that active means of responding are met by harsh, intrusive responses. Conditions marked by passive coping styles and disengagement have been linked with blunted stress responses. An extreme form of low responsivity, dissociation, has been directly associated with heart rate deceleration (d'Andrea, Pole, DePierro, Freed, & Wallace, 2013). Internalizing disorders such as subclinical depression, which are typically marked by social withdrawal, have also been linked to blunted heart rate and RSA responding (Bylsma, Salomon, Taylor-Clift, Morris, & Rottenberg, 2014; Franzen & Brinkmann, 2015). Furthermore, researchers have posited that a blunted neurological response to reward, which often accompanies withdrawal and passivity, is closely linked to a blunted response to stress (Ginty, 2013).

Psychological control in early adolescence may also contribute to blunted cardiovascular functioning in adulthood simply via the chronic stress it is likely to produce as development progresses. One study notably found that young adults with a history of being bullied showed a blunted heart rate response to stress (Newman, 2014). There is reason to believe that psychological control from parents could create a similar sense of threat and intimidation that would to lead to blunting, though this has not yet been examined. In addition to threatening a fundamental developmental need for autonomy, psychological control has the potential to undermine the connection between the adolescent and his or her attachment figures during this important transition. Psychological control is therefore likely to be particularly painful and anxiety-producing for the adolescent, and exposure to such chronic pain and stress may well contribute to the development of blunted cardiovascular responses (de Rooij, 2013; Gorman & Sloan, 2000; Jansen et al., 1998; MacMillan et al., 2009).

In addition, over time, the passive style of interacting adopted by adolescents experiencing psychological control is likely to lead to long-term social difficulties, and subsequently, substantial distress (Bhat & Aminabhavi, 2011). A passive, non-assertive style is likely to result in a failure to negotiate needs in relationships, thus creating a chronic source of distress that could further contribute to response blunting. Moreover, developmental cascade theory (Masten & Cicchetti, 2010) suggests that the effects of early parental psychological control are likely to cascade forward into new relationships over time in multiple ways, in a vicious cycle. Such interpersonal stressors seem particularly likely to be implicated in the development of blunted cardiovascular responding, as they tend to be chronic and are likely to present across many types of relationships and situations.

This paper tests the hypothesis that parental behavior disrupting autonomy development will generate a pattern of chronic stress and will have effects that are longer-lasting and further-reaching than previously assumed. It is hypothesized that the stress of psychological control in early adolescence will directly predict blunted heart rate and RSA reactivity under stress in adulthood. In addition, we predict that psychological control will predict a series of intervening behaviors reflecting withdrawal from key social interactions as well as passivity, ultimately predicting deficits in basic processes of physiological reactivity in adulthood. These factors were all examined within a diverse community sample that was followed longitudinally from early adolescence to adulthood.

It is specifically hypothesized that:

1. Parental psychological control at age 13 will predict blunted heart rate as well as blunted RSA reactivity under stress at age 29.

2. Parental psychological control at age 13 will predict greater withdrawal in key relationships, coping via denial, and disengagement across development.

3. Greater withdrawal, coping via denial, and disengagement will each predict blunted heart rate and RSA reactivity to stress at age 29.

4. Withdrawal, coping via denial, and disengagement will mediate the relationship between psychological control at age 13 and indicators of blunted cardiovascular responding at age 29.

Methods

Interview and observational data were obtained longitudinally for a community sample of 184 adolescents (86 males, 98 females) along with friends and romantic partners, first assessed in seventh and eighth grade (Mean age = 13.3 years), and re-interviewed annually up through age 29. The sample was demographically diverse and representative of the population from which it was drawn (baseline median family income was in the $40,000 to $59,000 range; the sample was 58% European-American, 29% African-American, 1% Asian, 1% Hispanic, .5% American Indian, 8% mixed race, and 2% other races/ethnicities). Adolescents were originally recruited from the seventh and eighth grades at a public middle school drawing from suburban and urban populations in the Southeastern United States. Students were recruited via an initial mailing to all parents of students in the school, along with follow-up contact efforts at school lunches. Adolescents who indicated they were interested in the study were contacted by telephone. Of all students eligible for participation, 63% agreed to participate either as target participants, or as peers providing collateral information.

For the purposes of the present study, data were drawn from eight time points: First in early adolescence with participants and their close friends (participant M age = 13.35, SD = 0.64); next, three times in mid-adolescence with participants and their close friends (participant M age = 14.27, SD = .77; participant M age = 15.21 SD = .81; and participant M age = 16.35, SD = .87); and next, two late adolescent assessments of target participants and their romantic partners (participant M age = 18.33, SD = 0.95, range = 15.4 - 21.6 and participant M age = 20.98, SD = 1.08, range = 18.6 - 24.2). During this time period, participants also reported on the amount that they valued self-direction. Next, data were collected at an early adulthood assessment of the target participants and romantic partners (participant M age = 23.78, SD = 0.97, range = 21.9 - 28.9). During this time period, participants’ close friends reported on the degree to which participants engaged in coping via denial. Finally, participants completed an adult assessment of their cardiovascular response to stress (M age = 28.55, SD = 1.03).

From ages 13-16, participants nominated a close friend to participate in the study and to participate in filmed interaction tasks. Close friends were defined as “people you know well, spend time with, and whom you talk to about things that happen in your life.” These close friends were chosen by the teen and may or may not have reciprocally considered the target teen to be their closest friend. At age 13, close friends reported that they had known the participants for an average of 4.02 years (SD = 2.88). At age 14, close friends reported knowing the participants for an average of 4.27 years (SD = 3.09). At age 15, close friends reported knowing the participants for an average of 5.07 years (SD = 3.41). At age 16, close friends reported knowing the participants for an average of 5.72 years (SD = 3.82). Twenty participants (10.87%) brought the same friend to all four assessment points.

At the age 18, 21 and 24 assessments, participants in a romantic relationship of at least 3 months were invited to participate in videotaped interaction tasks with their romantic partners. To maximize the number of romantic partners able to participate, dyads were recruited if they had an eligible romantic partner at any time within a span of three years to complete observational and questionnaire measures. At the age 18 data collection, 75 (41%) of the original participants were in eligible romantic relationships and both they and their partners agreed to participate. Participants reported an average relationship length of 1.18 years (SD = 1.25 years). At the age 21 data collection, 99 (54%) of the original participants were in eligible romantic relationships and both they and their partners agreed to participate. They reported average relationship duration of 1.82 years (SD = 1.76 years). At the age 24 data collection, 84 dyads (46% of the original sample) were eligible and agreed to participate. Participants reported an average relationship duration of 2.40 years (SD = 2.24 years). Five participants (4.17%) brought the same romantic partner to all three romantic partner visits.

Attrition

Attrition analyses were conducted to determine whether individuals who did vs. did not participate at a given wave differed in terms of the previously measured constructs. Adolescents who had friendships characterized by more withdrawal at age 13 were less likely to participate with friends between ages 14 and 16 (t = −3.28, p = .01). Females were significantly more likely to participate between ages 18 and 26 than males (χ² = 5.20, p = .02). Analyses also indicated that female participants were significantly more likely to participate at age 29 (χ2 = 10.51, p = .001). There were no other significant differences between those who did vs. did not participate at any of the waves in terms of gender, family income, or earlier levels of the variables measured.

To best address any potential biases due to attrition and missing data in longitudinal analyses, full information maximum likelihood methods were used, with analyses including all variables that were linked to future missing data (i.e., where data were not missing completely at random). Because these procedures have been found to yield less biased estimates than approaches (e.g., simple regression) that use listwise deletion of cases with missing data, the entire original sample of 184 for the larger study was utilized for these analyses. This analytic technique does not impute or create any new data nor does it artificially inflate significance levels. Rather, it simply takes into account distributional characteristics of data in the full sample so as to provide the least biased estimates of parameters obtained when some data are missing (Arbuckle, 1996).

Measures

Psychological control from parents (Age 13).

Adolescents completed the 10-item Psychological Control vs. Psychological Autonomy subscale of the Childhood Report of Parenting Behavior (Schaefer, 1965). Adolescents reported on the extent to which their mothers and fathers used psychologically controlling behaviors and the scores for the two parents were averaged together (or the score for a single parent was used). Example items include “My mother [father] figure wants to control whatever I do.” “says if I really cared for her [him], I would not do things that cause her [him] to worry.” Internal consistency was acceptable (Cronbach’s α =.77).

Observed withdrawal in relationships (Ages 13-16, 18-26).

From ages 13-16 and 18-26, participants and their close friends (13-16) or romantic partners (18-26) participated in a revealed differences task in which they had to come to a consensus on either a hypothetical disagreement task (through age 21) or with respect to the most substantive area of disagreement they separately identified (age 21 on). Tasks were chosen to be developmentally appropriate (i.e., younger adolescents may not have substantive areas of disagreement with friends and romantic partners, hence the use of a hypothetical task). The scale taps four types of behaviors: Stating reasons for a position, confidence, displays of positive connectedness, and active collaborative behavior (all reverse-scored to capture withdrawal). The coding system employed yields ratings from zero to four for each participant’s overall behavior toward his/her partner in the interaction with lower scores indicating more withdrawal (Allen, Hauser, Bell, & McElhaney, 2000; Allen et al., 1994). Participants’ and partners’ scores were averaged together to capture the amount of autonomy and relatedness shown at the dyadic level, an approach previously found to yield highly valid data (Allen et al., 2003). Interrater reliability at the dyadic level was calculated using intraclass correlation coefficients and was in what is considered “good” to “excellent” range for this statistic across years (Intraclass r = .69 - .85; Cicchetti & Sparrow, 1981).

Disengagement (Ages 20-21).

Participants completed the Self Direction subscale from The Parent Values Measure (Kohn, 1977; Schaefer & Edgerton, 1985), reporting on their own valuing of self-direction. Example items include: “To think for myself” and “To be curious about many things.” The self-direction score was computed by adding the ranking of those items. Although Cronbach’s alpha is not a perfect indicator for a rank system, internal consistency was classified as poor (Cronbach’s α = .53-.57).

Coping via denial (Ages 22-24).

We used the two-item denial coping subscale from the Brief COPE, as reported by the participant’s identified close friend. The COPE has been used in a number of health-related studies and evidence suggests that it assesses coping processes that are predictive of prospective physiological effects (Antoni et al., 1991; Antoni et al., 1995; Carver, 1997; Carver et al., 1993). The items include: “He/she usually says that ‘this isn’t real” and “He/she usually refuses to believe that it has happened.” Internal consistency across years was marginal to good (Cronbach’s α = .65-.87).

Blunted heart rate response to stress (Age 29).

Blunted heart rate reactivity was calculated as the inverse of reactivity (i.e., −1 X heart rate under stress – baseline heart rate) during the Trier stressor tasks (Cacioppo et al., 1995; Kirschbaum, Pirke, & Hellhammer, 1993), a well-established protocol for studies of stress reactivity. Participants completed a resting period, a speech task, a math task, and a recovery period. Heart rate was continuously monitored throughout the tasks using a Mindware 2000D module. Five-lead electrodes were placed according to standard ECG placement recommendations (Hoetink et al., 2002) and each waveform was verified or edited prior to analyses. The stress tasks consisted of a standard speech task, in which participants were told to imagine that they were in a department store shopping and the security guard falsely accused them of shoplifting a belt. Next, participants were asked to subtract numbers out loud for six minutes. If they gave an incorrect response, they were corrected and told to begin from the corrected number.

Blunted respiratory sinus arrhythmia reactivity to stress (Age 29).

Blunted RSA reactivity was calculated as the inverse of reactivity (i.e., −1 X RSA under stress – baseline RSA) during the tasks described above. RSA was calculated based on the digitized inter-beat-intervals (see above). Following linear detrending, the heart period time series was band pass filtered from .12 to .40 Hz (Berntson, Cacioppo, & Quigley, 1993; Litvack, Oberlander, Carney, & Saul, 1995). The power spectrum of the heart period time series was calculated using a Fast Fourier Transform and scaled to msec²/Hz. RSA was calculated as the natural log of the area under the heart period power spectrum within the corner frequencies of the band pass filter (Litvack et al. 1995). RSA was calculated on a minute by minute basis and aggregated across minutes within each epoch to increase measurement reliability.

Results

Preliminary Analyses

Table 1 presents means, standard deviations, and intercorrelations of substantive variables. We also examined the possible moderating effects of the block of gender and family income on each of the relations described in the primary analyses below by creating interaction terms based on the product of centered main effect variables. No significant interactions were found with the block of gender and income. However, given interest and the importance of gender in cardiovascular reactivity (Kudielka, Buske, Kirschbaum, Hellhammer, & Kirschbaum, 2004), we considered gender separately and found that women with higher levels of disengagement also had a more blunted heart rate under stress (t = 2.31, p = .02). This suggests that disengagement may be particularly associated with a blunted heart rate for women, though this finding was not significant when tested in a block with income, which we consider a more rigorous test.

Table 1.

Correlations Among and Descriptive Statistics for Key Study Variables

	M (SD)	N	1.	2.	3.	4.	5.	6.	7.	8.	9.	10.
1. Psych. Control (13)	15.21 (3.50)	183	--	24**	37***	34***	35***	37***	−35***	12	06	−32***
2. Withdrawal with Friends (13)	1.62 (.60)	178		--	30***	39***	32***	23**	−24**	−12	−08	−31***
3. Withdrawal with Friends(14-16)	1.57 (.35)	175			--	45***	30***	31***	−36***	−15	05	−27**
4. Withdrawal with Romantic Partners (18-26)	1.67 (.39)	129				--	39***	44***	−47***	−31***	11	−27**
5. Disengagement (20-21)	19.62 (3.93)	166					--	30***	−30***	−15	31***	−20**
6. Coping via Denial (22-24)	.78 (1.00)	160						--	−24**	22**	12	−31***
7. Heart Rate Reactivity (29)	8.22 (6.63)	138							--	−46***	−10	27**
8. RSA Reactivity (29)	−.02 (.77)	141								--	01	−07
9. Gender (1=Male, 2=Female)	--	184									--	−11
10. Family Income (13)	43,600 (22,4000)	181										--

^**p < .01.

^***p <.001.

Primary Analyses

Primary analyses were conducted via linear regression using full information maximum likelihood analyses in MPlus (Version 8.1; (Muthén & Muthén, 2015).

Hypothesis 1: Parental psychological control at age 13 will predict blunted heart rate and RSA reactivity to stress at age 29.

Analyses first examined whether parental psychological control in early adolescence would predict a blunted heart rate response under stress by age 29. As shown in Table 2, after controlling for gender, family income, participant age, and body mass index at age 29, parental psychological control at age 13 predicted a more blunted heart rate in response to stress at age 29 (β = .29, p = .001). This suggests that, even after accounting for a range of potential covariates, adolescents who reported high levels of psychological control from their parents were likely to have a relatively more blunted heart rate response to stress at age 29. However, accounting for the same covariates, parental psychological control at age 13 did not significantly predict blunted RSA reactivity (β = .11, p = .22).

Table 2.

Predicting Blunted Heart Rate Reactivity Under Stress (Age 29) from Early Adolescent Psychological Control (Age 13)

	Blunted Heart Rate Reactivity (Age 29)
	β entry	β final	ΔR2	Total R2
Control Variables
Step I.
Gender (1=M; 2=F)	.07	.01
Total Family Income (13)	−.26***	−.14
Statistics for Step			.076	.076
Step II.
BMI (Age 29)	.20**	.19**
Age at Visit	−.15	−.14
			.063**	.139**
Hypothesized Predictor
Step III.
Psychological Control (Age 13)	.29***	.29***
			.060**	.199***

Note.

^***p < .001.

^**p < .01.

Hypothesis 2: Parental psychological control at age 13 will predict greater withdrawal, disengagement, and coping via denial across development.

Analyses next examined parental psychological control in early adolescence as a predictor of later withdrawal, disengagement, and coping via denial. Accounting for gender, family income, and withdrawal in a friendship at age 13, parental psychological control at age 13 predicted relative increases in withdrawal in friendships (i.e., accounting for baseline withdrawal) from age 13 to age 16 (β = .29, p = .001); see Table 3. In addition, accounting for gender, family income, and withdrawal in a friendship at age 13, parental psychological control at 13 predicted higher levels of withdrawal in romantic relationships at ages 18 to 26 (β = .24, p = .003); see Table 3. This suggests that adolescents who reported greater levels of parental psychological control at 13 displayed more withdrawn behavior in both their friendships and romantic relationships as they moved from early adolescence to early adulthood. Next, accounting for demographic variables, greater parental psychological control at age 13 predicted greater levels of disengagement by age 21 (β = .31, p = .001); see Table 4. Finally, using the same approach, greater parental psychological control at age 13 predicted higher levels of coping via denial by age 23 (β = .30, p = .001); see Table 4. This suggests that parental psychological control was predictive of greater use of coping via denial by age 23.

Table 3.

Predicting Withdrawal with Friends (Age 14-16) and Romantic Partners (Age 18-26) from Early Adolescent Psychological Control (Age 13)

	Withdrawal with Friends (Age 14-16)				Withdrawal with Romantic Partners (Age 18-26)
	β entry	β final	ΔR2	Total R2	β entry	β final	ΔR2	Total R2
Control Variables
Step I.
Gender (1=M; 2=F)	.02	.01			.08	.06
Total Family Income (13)	−.28***	.12			.25**	.11
Statistics for Step			.079	.079*			.073	.073
Step II.
Baseline level of Withdrawal (Age 13)	.24***	.20**			.34***	.30***
			.049**	.128**			.112***	.185**
Hypothesized Predictor
Step III.
Psychological Control(Age 13)	.29***	.29***			.24**	.24**
			.074***	.202***			.059**	.244***

Note.

^***p < .001.

^**p < .01.

Table 4.

Predicting Disengagement (Age 21) and Coping via Denial (Age 23) from Early Adolescent Psychological Control (Age 13)

	Disengagement (Age 21)				Coping via Denial (Age 23)
	β entry	β final	ΔR2	Total R2	β entry	β final	ΔR2	Total R2
Control Variables
Step I.
Gender (1=M; 2=F)	.29***	.28***			.09	.09
Total Family Income (13)	−.17*	.07			−.31***	−.21**
Statistics for Step			.124	.124**			.109	.109*
Hypothesized Predictor
Step II.
Psychological Control (Age 13)	.31***	.31***			.30***	.30***
			.079***	.203***			.084***	.193***

Note.

^***p < .001.

^**p < .01.

^*p < .05.

Hypothesis 3: Greater withdrawal, coping via denial, and disengagement will each predict more blunted heart rate and RSA reactivity to stress at age 29.

Next, analyses examined whether each of the markers of passivity would predict a blunted heart rate response under stress, accounting for gender, family income, and age 13 levels of withdrawal with close friends (see Table 5). When examined separately, each marker of passivity significantly predicted a blunted heart rate response. The effect for withdrawal with close friends from 14-16 was β = .27, p = .002; the effect from withdrawal with romantic partners from 18-26 was β = .39, p = .001; the effect from disengagement at age 21 to a blunted heart rate response was β = .23, p = .01; and the effect from coping via denial at age 23 to a blunted heart rate response was β = .22, p = .01. Because these all emerged as significant predictors, all four were examined as potential mediators.

Table 5.

Predicting Blunted Heart Rate Reactivity Under Stress (Age 29) from Withdrawal with Friends (Age 14-16), Withdrawal with Romantic Partners (Age 18-26), Disengagement (Age 21), and Coping Via Denial (Age 23)

	IIIa. Withdrawal with Friends				IIIb. Withdrawal with Romantic Partners				IIIc. Disengagement				IIId. Denial
	β entry	β final	ΔR2	Total R2	β entry	β final	ΔR2	Total R2	β entry	β final	ΔR2	Total R2	β entry	β final	ΔR2	Total R2
Step I.
Gender (1=M; 2=F)	.07	.04			.07	.05			.07	.02			.07	.03
Total Family Income (13)	−.26***	−.16			−.26***	−.13			−.26***	−.19*			−.26***	−.15
Step Statistics			.076	.076			.076	.076			.076	.076			.076	.076
Step II.
Baseline level of Withdrawal (Age 13)	.16	.08			.16	.02			.16	.10			.16	. 13
			.020	.096*			.020	.096*			.020	.096*			.020	.096*
Step IIIa: Withdrawal with Friends (14-16)	.27**	.27**			--	--			--	--			--	--
			.056**	.152**			--	--			--	--			--	--
Step IIIb. Withdrawal with Romantic Partners (18–26)					.39***	.39***			--	--			--	--
							.119***	.215***			--	--
Step IIIc. Disengagement (21)									.23**	.23**			--	--
											.040*	.136**			--	--
Step IIId. Denial (23)													.22**	.22**
															.046*	.142**

Note.

^***p < .001.

^**p < .01.

^*p < .05.

When examining predictions to RSA, only withdrawal with romantic partners from ages 18-26 (β = .31, p = .001) and coping via denial at age 23 (β = .21, p = .02) significantly predicted blunted RSA reactivity under stress at age 29 (see Table 6). The association from withdrawal with friends from ages 14-16 to blunted RSA reactivity was β = .12, p = .20 while the association from disengagement at age 21 to blunted RSA reactivity was β = .14, p = .12. Because only withdrawal with romantic partners and coping via denial emerged as significant predictors of RSA reactivity, these two were examined as potential mediators.

Table 6.

Predicting Blunted Respiratory Sinus Arrythmia Reactivity Under Stress (Age 29) from Withdrawal with Romantic Partners (Age 18-26)and Coping Via Denial (Age 23)

	IIIa. Withdrawal with Romantic Partners				IIIb. Denial
	β entry	β final	ΔR2	Total R2	β entry	β final	ΔR2	Total R2
Step I.
Gender (1=M; 2=F)	−.01	−.04			−.01	−.04
Total Family Income (13)	−.08	.04			−.08	.02
Step Statistics			.006	.006			.006	.006
Step II.
Baseline level of Withdrawal (Age 13)	.12	.01			.12	.09
			.012	.018			.012	.018
Step IIIa. Withdrawal with Romantic Partners (18-26)	.31***	.31***			--	--
			.074**	.092
Step IIIb. Denial (23)					.21*	.21*
							.040*	.058

Note.

^***p < .001.

^**p < .01.

^*p < .05.

Hypothesis 4: Withdrawal, coping via denial, and disengagement will mediate the relationship between psychological control at age 13 and blunted cardiovascular responses at age 29.

Finally, the hypotheses regarding mediation were tested. As shown in Figure 1, greater withdrawal in friendships from ages 14-16, greater withdrawal in romantic relationships from ages 18-26, greater disengagement at age 21 and greater coping via denial at age 23 together mediated the relationship between psychological control at 13 and a blunted heart rate response under stress at age 29, as assessed via model indirect in Mplus, using bootstrapped confidence intervals (Preacher & Hayes, 2008). The link between psychological control and blunted heart rate response was no longer significant with the mediators in the model, suggesting full mediation. The total indirect effect from psychological control to passive behaviors to blunted heart rate response was −.134, 95% CI = −.24; −.03. When examined separately, only the path from psychological control through withdrawal in romantic relationships to a blunted heart rate response was significant (indirect effect = −.06, 95% CI = −.13; −.004). This suggests that, together, withdrawal, denial, and disengagement, fully mediated the relation between psychological control and a blunted heart rate response and that this effect was mainly driven by withdrawal in romantic relationships.

Figure 1.

Mediation model of psychological control at 13 to blunted heart rate reactivity at age 29, via withdrawal with friends (age 14-16), romantic partners (age 18-26), disengagement (age 21) and coping via denial (age 23).

In terms of blunted RSA reactivity, as shown in Figure 2, there was a significant indirect effect from psychological control to blunted RSA reactivity through withdrawal in romantic relationships from ages 18-26 and coping via denial at age 23 (indirect effect = .106, 95% CI = .04; .20). When examined separately, only the indirect effect of withdrawal in romantic relationships was significant (indirect effect = .062, 95% CI = .02; .13). The confidence interval of the effect through coping via denial contained zero (indirect effect = .044, 95% CI = −.01; .11). This suggests that, while there was not a direct effect from psychological control in early adolescence to a blunted RSA reactivity in adulthood, there was an effect through withdrawal in romantic relationships.

Figure 2.

Mediation model of psychological control at 13 to blunted RSA reactivity at age 29, via withdrawal with romantic partners (age 18-26) and coping via denial (age 23).

Discussion

This long-term, multi-method study identified a previously unrecognized potential social-developmental pathway from a range of interpersonal behaviors beginning in adolescence to disruption of basic physiological and social processes in adulthood. Psychologically controlling parental behavior at age 13 was found to be directly predictive of a blunted heart rate response and indirectly predictive of blunted RSA reactivity to stress at age 29.

Research into a wide variety of physiological systems (e.g., circulatory, endocrine) has shown that both hyper- and hypo- activation of these systems are linked to stress and predict poor health outcomes (Phillips et al., 2013; Tsigos & Chrousos, 2002). There are several different possibilities as to why people who have experienced chronic stress may develop a blunted rather than a heightened physiological response: These include reduced effort and/or motivation in the face of a challenge, a general desensitization to negative stimuli, or reduced physiological capacity to respond, perhaps following a period of chronic arousal (Phillips et al., 2013). There is some evidence, from both studies with humans and rats that repeated, uncontrollable stress is related to blunting rather than a heightened response (d’Andrea et al., 2013; McTeague, Lang, Laplante, Cuthbert, Shumen, & Bradley, 2010; Thompson, Christianson, Maslanik, Maier, Greenwood, & Fleshner, 2013). Interestingly, there are established links between both blunted heart rate as well as blunted RSA reactivity with depression, which is often characterized by difficulties with motivation and effort as well as heightened negative affect (Bylsma et al., 2014; Schwerdtfeger & Rosenkaimer, 2011). We posit that adolescents who experience the insidious stressor of overcontrolling parenting could well have both difficulty physiologically rising to the challenge of a stressor, which involves both upregulating sympathetic and downregulating parasympathetic functions.

Blunted heart rate reactivity in turn has been implicated in a variety of negative health outcomes, such as obesity, depression and anxiety, poor lung function, poor cognitive function, poorer self-reported health, and death from cardiac events (Carroll et al., 2012; de Rooij, 2013; Phillips, 2011; Phillips et al., 2013). Similarly, blunted RSA reactivity is associated with a variety of mental health and emotion regulation concerns (Porges, 2007). The current findings are consistent with the idea of allostatic load: Individuals who experience chronic stressors are compromised in their ability to respond physiologically to maintain homeostasis. The current study also found that several interpersonal factors in mid to late adolescence and early adulthood were identified as predictive of cardiovascular functioning, and several of these were in turn also identified as potential mediators of the long-term effects of parental psychological control at age 13. Given the numerous health concerns associated with blunted heart rate and RSA reactivity, identification of pathways potentially leading to such response patterns can both inform causal models of the development of dysfunctional stress response systems in humans and eventually inform interventions to alter these pathways. Taken together, results of this study suggests a pathway by which controlling and autonomy-undermining parental behavior may lead to a broader set of problematic social behaviors, which over time are linked to a maladaptive physiological response pattern.

We posited two mechanisms by which this phenomenon may play out. One involves a problematic pattern of withdrawal and disengagement, established in adolescence and extending through mid-adulthood. The current study found that psychological control in early adolescence was associated with the development of a tendency to withdraw in both friendships and romantic partnerships. One explanation for these findings is that adolescents who experience parental psychological control learn, implicitly or explicitly, that asserting oneself or overtly acknowledging problems as they arise is pointless or even dangerous, as such attempts are likely to be met with hostility or the threat of love withdrawal. These adolescents are likely to enter into relationships in which assertiveness and demonstration of emotions are suppressed during conflict, in favor of withdrawal. Such a style of conflict could lead directly to feelings of stress; moreover, these interpersonal styles might lead to a failure to advocate for one’s needs, thus leading to increased stress going forward (Heavey, Christensen, & Malamuth, 1995; Siffert & Schwarz, 2011; Thomson, Overall, Cameron, & Low, 2018). These participants also went on to cope by denying the existence of problems. Importantly, participants’ use of denial coping was reported by independent observers (close friends). Individuals experiencing parental psychological control appear to have learned that attempting to actively cope with problems was futile, particularly as they learned that they should not think for themselves or try to effect change.

The pattern of interpersonal linkages observed over time is consistent with a developmental argument that difficulties earlier in development will often continue to cascade forward across domains (Oudekerk, Allen, Hessel, & Molloy, 2015). Our finding that psychological control was associated with increasing withdrawal over time is consistent with previous research with children that found that intrusive maternal behavior was linked to both concurrent and later social withdrawal (Booth-LaForce & Oxford, 2008; Mills & Rubin, 1998). The current study builds on prior findings by examining the developmental course of withdrawal starting in adolescence and then extending through early adulthood as a precursor to blunted physiological responding. In addition, this study examined tendencies not just to withdraw but also to find partners who adopted similar, low-conflict, low-assertiveness strategies. Overall, this pattern of relational withdrawal was also observed across time, partners, and type of relationship (friendship and romantic relationship) in a remarkably consistent fashion. This suggests that it became an enduring element of individuals’ response patterns, which further helps explain the ultimate link to physiological response patterns.

The second, nonexclusive pathway involves chronic stress overload. Adolescents whose autonomy is undermined and who go on to develop a passive pattern of behavior are likely to experience substantial stress and difficulty at key developmental stages. There is a good deal of research to suggest that the accumulation of chronic levels of stress will predict blunting in a range of physiological response systems including cortisol, blood pressure, and epinephrine response (Burke, Davis, Otte, & Mohr, 2005; Koo-Loeb et al., 1998; MacMillan et al., 2009). This suggests that the biological systems of those who experience stress tend to be less responsive to stressful stimuli and that physiological blunting is a common outcome of repeated stress. The findings that a specific social process, psychological control, occurring in early adolescence appears to be directly associated with blunting of the heart rate response and indirectly associated with blunting of RSA reactivity in adulthood provides an exciting new avenue to understanding the social-developmental roots of such blunting. These findings are consistent with previous research that found that adolescence was a particularly sensitive period for health-related outcomes into adulthood (Allen, Loeb, Tan, Narr, & Uchino, 2018; Allen, Uchino, & Hafen, 2015). These findings also suggest that it may be important to involve parents in interventions, to improve adolescents’ future health outcomes. A prior study found that an intervention designed to improve parenting had positive effects on markers of inflammation eight years later (Miller, Brody, Yu, & Chen, 2014). If these results were further replicated and evidence of the causal relationship was solidified, the current study would suggest cardiovascular reactivity might similarly benefit. In addition, interventions such as assertiveness training in adolescence and young adulthood may be of particular relevance to cardiovascular functioning.

There are some important limitations to note in the current study. Perhaps most importantly, we did not have access to cardiovascular functioning prior to age 29. This means we cannot account for a potential reverse causal direction in our model. However, it seems less plausible that adolescents with a blunted heart rate response to stress would be eliciting psychological control from parents. It is similarly unlikely that RSA reactivity was a dispositional feature driving the problems in relationships and behaviors observed (especially given research showing blunted RSA reactivity in current depressed but not previously depressed individuals [Bylsma et al., 2014]), but this possibility cannot be completely discounted. We also cannot examine the possibility that the observed blunting may have been preceded by a period of chronic arousal, perhaps in childhood or adolescence. Future studies would do well to examine predictors of change in cardiovascular reactivity over time. In addition, in our combined mediation models predicting both heart rate and RSA reactivity, we found that withdrawal with romantic partners emerged as the only significant mediator when potential mediators were tested simultaneously. That said, it is important to note that the collection period for this variable ended closest in time to the cardiovascular reactivity assessment, which may account for its apparent significance. Next, although we found indirect predictions from early psychological control to cardiovascular functioning through passive/withdrawn behaviors, the underlying physiological mechanism that produces these responses is still not clear. However, the current research lends support to the idea that cardiovascular blunting may be the result of dysfunction in the parasympathetic nervous system (reflected in RSA reactivity; possibly reflected in heart rate reactivity) and potentially the sympathetic nervous system (possibly reflected in heart rate reactivity). Future longitudinal research could measure physiological functioning throughout adolescence and early adulthood to better understand the development of blunted cardiovascular responding. Similarly, although our use of lagged data allows us to understand the development of problems over time, the data is not experimental and does not allow us to make causal arguments. While our sample was diverse and representative of the population from which it was drawn, we are also unable to make cross-cultural comparisons. For instance, while there is some evidence that psychological control is problematic cross-culturally (Vansteenkiste, Zhou, Lens, & Soenens, 2005), there is other evidence that parenting characteristics that are considered maladaptive in Western cultures (e.g., extremely close relationships and diffuse boundaries between parent and child) may be normative or even adaptive in certain Asian cultures (Rothbaum, Rosen, Ujiie, & Uchida, 2002). Therefore, psychological control cannot be assumed to function in the same way cross-culturally.

Data Availability Statement:

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.