Effect of maternal psychopathology on behavioral problems in preschool children exposed to terrorism: use of generalized estimating equations to integrate multiple informant reports

Abstract

Objective:

Using child behavior ratings from multiple informants, we examined whether the number of maternal psychological disorders is associated with increased clinically-significant behavioral problems among disaster-exposed preschool children.

Design:

Cross-sectional design.

Setting:

Lower Manhattan, New York, USA

Participants:

102 preschool child-mother dyads directly exposed to the WTC attacks.

Main Exposure:

Maternal disorders [two (PTSD and depression), one (depression or PTSD), none].

Outcome Measures:

Maternal depression and PTSD were self-reported. Child behavioral problems were rated by mothers and by teachers using a standardized behavioral checklist. For each informant, we created separate dichotomous variables representing whether the child’s behavioral problems were severe enough to be clinically significant. We then used an analytic technique (Generalized Estimating Equations) that integrates the child behavior problem ratings of mother and teachers to derive a more reliable indicator of clinically-significant child behavior problems.

Results:

The rate of clinically-significant child behavioral problems increased linearly relative to number of maternal disorders. Number of maternal psychological disorders was associated with a linear increase in functional impairment. Compared to children of mothers without psychological disorders, children of mothers with depression and PTSD were at greater risk for several clinically-significant problems; notably aggressive behavior (relative risk=13.0), emotionally reactivity (relative risk=11.2), and somatic complaints (relative risk=10.5). Boys were more likely to have clinically-significant behavior problems than girls.

Conclusion:

Co-occurring maternal depression and PTSD was associated with dramatic increases in the rate of clinically-significant behavior problems among preschool children, particularly boys, three years after the WTC attacks.

Although there is evidence that preschool children are highly vulnerable to the effects of armed conflict,^{1, 2} little is known about the effects of terrorism on preschool children.^3–7 Very young children are likely to be affected by direct exposure to terrorism, as well as to be affected indirectly by the consequences of their mothers’ exposure to terrorism preschool children directly exposed to terrorism and to other-trauma are much more likely to have clinically significant behavioral problems than children exposed to terrorism only, to other-trauma only, or to neither.⁸ This is consistent with McEwen’s theory of allostatic load.²³

While the effect of parental depression on child problems and psychopathology has been well-established,^13–16 to date, only a limited number of studies have evaluated the effect of maternal post-traumatic stress on child problems and psychopathology.^17–21 Despite the fact that post-traumatic stress disorder (PTSD) and depression occur most frequently among adults post-diaster²², few studies have examined their impact as co-occurring psychological reactions on children following exposure to disaster. Moreover, there has been very little research conducted in quantifying the impact of maternal psychopathology as an indirect contributor to the behavior problems of young children in the aftermath of terrorism and disasters¹. A recent prospective investigation of trauma-exposed youth¹⁹ suggests that factors such as cumulative lifetime trauma exposure may account for elevations in youth posttraumatic distress, when simultaneously entered into regression models with parent PTSD and/or depression. Thus, it is possible that maternal elevations in PTSD or depression symptoms are a proxy for prior trauma exposure. To our knowledge, no studies have examined the effects of terrorism-related maternal PTSD and depression, together with child and mother exposure to terrorism and other-trauma, on child behavior problems.

Guided by the concept of allostatic load, we reasoned that a maternal disorder would represent indirect exposure to the effects of terrorism for very young children because of its effects on maternal symptoms and impairment. We predicted that the number of disorders a mother suffers would be associated with a linear increase in maternal impairment. Further, we predicted that the number of maternal disorders would be associated with a greater adverse impact on children’s behavioral problems following terrorism exposure. Specifically, we hypothesized that the children whose mothers have two disorders (PTSD and depression) in the aftermath of exposure to the WTC attacks would be at greater risk for behavioral problems compared to children whose mothers had only one disorder (either PTSD or depression), and children whose mothers had neither disorder.

METHODS

This study was approved by the Mount Sinai School of Medicine’s Institutional Review Board. It was conducted between March 2003 and December 2005 (a mean of 35 months after the WTC attacks, range 18–54 months) to assess the longer-term impact of WTC-attack exposure on preschool children. Families with children born between 9/11/96 and 9/11/02 were included if: 1) the children lived in Lower Manhattan, or 2) attended preschool or daycare in Lower Manhattan on the day of the WTC attacks.

Families were recruited using extensive outreach in the Lower Manhattan area. Procedure details are described elsewhere⁶¹. This study’s sample comprised 102 child-mother dyads for whom both parent and teacher ratings were available. Participants who dropped out of the study did not differ on age, gender, race, or SES from completers.

MEASURES

Demographics

Age, ethnicity of the child, and maternal education were reported by the mother.

Child behavioral and emotional problems

We used the preschool version of the Child Behavior Checklist (CBCL/1·5–5)²⁸ to measure children’s problems. The preschool CBCL is an established psychometric measure.²⁸ The 7 CBCL scales were our indices of child behavioral problems. Age and gender standardized T-scores were calculated for each scale (emotionally reactive, anxious/depressed, somatic complaints, withdrawn, sleep problems, attention problems, and aggressive behavior). A problem score equal to or greater than 65 (reflecting a score at or above the 93^rd percentile) is considered clinically significant and was used as our cut-off.

Teachers completed the preschool version of the Teacher Report Form(C-TRF)²⁸, a behavior rating checklist that comprises 6 of the 7 CBCL behavioral problem scales. The sleep problem cluster is not rated by teachers and was not included in our analyses. The C-TRF uses many of the same behavioral problem items as the CBCL but substitutes group situation items for family situation items. It has high test-retest reliability (mean r =.81) and good correlations with the CBCL (mean r =.40).²⁸

Maternal Psychopathology

The Center for Epidemiologic Studies-Depression Scale (CES-D)²⁹ was used to measure probable maternal depression. The 20-item scale assesses the frequency of depression symptoms rated on a 4-point Likert scale with excellent internal consistency^29,33. Probable maternal depression was dichotomized using the clinical cut-off score of 16.³⁰ Reliability of the CES-D has been demonstrated in clinical³¹ and epidemiological studies.^32–34 The CES-D has good sensitivity (80%) and specificity (68%) for identifying psychiatric illness.^35–37

The Posttraumatic Stress Diagnostic Scale (PDS)³⁸ was used to assess probable maternal PTSD. The PDS parallels the DSM-IV PTSD diagnostic criteria.³⁹ The PDS has a test-retest reliability kappa of .74 for PTSD diagnosis. It has a kappa of ·65 with the Structured Clinical Interview (SCID) for DSM-III-R, with 82% agreement between the two measures.⁴⁰ The sensitivity and specificity of the PDS with respect to SCID diagnosis is ·89 and ·75 respectively.³⁸ Mothers were considered to have PTSD if they met all six diagnostic criteria--exposure to a traumatic event; persistent re-experiencing symptoms; persistent avoidance of the stimuli associated with the trauma; persistent arousal; duration of the disturbance for longer than 1 month; and clinically significant functional impairment.

POTENTIAL CONFOUNDERS

Mother’s and child’s exposure to high-intensity WTC attack-related events

Maternal WTC attack exposure was measured by the mother’s dichotomous responses to 6 questions about direct exposure to high-intensity WTC attack-related events (personally saw a plane hit a tower, saw the tower collapse, saw injured people, saw dead bodies, saw people jumping out of the building, and were caught in the debris or smoke). Responses were summed to denote exposure level. Mothers reported on the extent to which their children had been directly the same WTC-related events. The same continuous index was created for children.³⁸

Child’s and mother’s exposure to other-traumatic experiences

Children’s exposure to trauma other than the WTC attacks was measured with a modified version of the Traumatic Events Screening Inventory (TESI)⁴¹ which measures exposure to events such as natural disasters, interpersonal losses, serious accidents, severe illnesses or injuries, animal attacks, exposure to war/terrorist acts, and exposure to suicide or attempted suicide. Physical and sexual abuse and domestic violence items were considered too sensitive by preschool administrators and teachers to use in the post-WTC attack environment and were omitted.³⁸

Maternal exposure to trauma was assessed using the PDS trauma event checklist³⁸ which includes such events as serious accidents, natural disasters, non-sexual or sexual assault by a stranger, or family member, military combat or involvement in war zone, imprisonment, torture, life-threatening events, and an open-ended “other” category.

Age of the child, time elapsed since the WTC attacks, and socioeconomic status (SES)

Children’s age and time elapsed since the WTC attacks were calculated based on the date of assessment, the child’s date of birth and 9/11/2001, respectively. SES was measured by maternal education, a reliable and valid index of SES.^42–43

STATISTICAL ANALYSIS

First, we evaluated the rate of each behavioral problem based on teacher’s and mother’s reports. This was followed by a regression analytic strategy, applying generalized estimating equations (GEE)^44–46 to estimate the effect of maternal psychopathology on children’s behavior problems, as rated by mothers and teachers. This statistical approach allows the use of information from multiple informants effectively, because it provides regression coefficients and their standard errors taking the correlation of ratings between mother and teacher reports into account. In our model, we included an interaction term between informant and maternal psychopathology risk, which determines whether data from multiple informants can be combined to yield a single, more precise, estimate of the effect of the risk factor. Thus, the potential bias due to mother’s or/and teacher’s report are accounted for by the interaction term and estimates are more accurate. We used the “unstructured” correlation as the covariance structure, which has no pre-set assumption on the structure, between mothers’ and teachers’ reports. In order to estimate the impact of maternal psychopathologies as cumulative risk to children, we constructed a three-category variable indicating whether mothers had no disorder (neither PTSD nor depression), one disorder (either depression or PTSD), or two disorders (PTSD and depression).

Rates of clinically significant child behavior problems in each maternal psychopathology group (no, one or two disorders) and overall group difference without any confounders and then with adjustment of confounders were calculated. Confounders were entered in a group in a following order. Step 1 included demographic and other confounders such as age and gender of the child, SES, and time elapsed since the attacks. Step 2 included child’s exposure variables, such as exposure to trauma and the WTC terrorism. Step 3 included mother’s exposure variables, such as exposure to other-trauma and the WTC attacks. The same set of analyses were repeated after stratifying on gender to evaluate whether there was gender-specific vulnerability in externalizing (for boys) and internalizing problems (for girls).

Furthermore, the exponential terms of the parameter estimates that represent odds ratios, were obtained first with the group where mothers with and without PTSD and depression as well as interaction terms between informants and each maternal psychopathology (PTSD and depression). Then, a three category maternal psychopathology (neither, one, or two disorders) was used in place for each individual maternal psychopathology. Estimated odds ratios were converted into relative risk (RR) as problems in child behaviors in this sample were not rare occurrence and that could substantially inflate the estimate of the risk. We used the converting formula presented by Zhang and Yu⁴⁷: $\text{RR}=\frac{\text{OR}}{(1-{\text{P}}_0)+({\text{P}}_0\times \text{OR})}$ Where P₀ indicates the incidence of the outcome of interest in the non-exposed group (i.e., children of mother with neither depression nor PTSD). 95% confidence intervals (CI) were also converted, accordingly. We entered potential confounders in stages as we did before, allowing us to see how different sets of potential confounders influenced the estimates. As some children were from the same family (n=13), the assumption of independent observations underlying standard errors and CI’s may be violated. Consequently, all GEE analyses were conducted while adjusting for possible non-independence of outcomes.

RESULTS

Participants

Table 1 shows demographics of the participants. There was no difference in demographic distribution. With regards to exposure to trauma, there was no difference on the level of exposure to the WTC attack-related trauma among children (p=.11) and mothers (p=.08). However, mothers with PTSD and depression, and their children, were more likely to have experienced other-traumatic events.

Table 1.

Descriptive Statistics for Study Variables by Maternal Psychopathology

Variable	Total sample	Neither	PTSD or depression	PTSD and depression
	M (SD)	M (SD)	M (SD)	M (SD)
	(n=102)	(n=62)	(n=26)	(n=14)	Statistics
Demographics
Child age (years)	3.69 (.94)	3.71 (1.03)	3.73 (.87)	3.50 (.64)	F=0.6, p=.52
Child gender (female), N (%)	49 (48%)	31 (50%)	13 (50%)	5 (35.7%)	X2(2)=2.0, p=.37
Mother age (years)	34.5 (8.0)	34.8 (1.7)	34.2 (1.3)	33.0 (1.5)	F=1.2, p=.36
Time since the WTC (months)	35.5 (11.7)	35.7 (12.3)	34.2 (11.7)	36.7 (9.0)	F=0.5, p=.60
Mother’s educationa	4.2 (1.8)	4.2 (1.8)	3.9 (1.9)	4.7 (1.4)	F=2.0, p=.13
Child exposures
WTC attack-related trauma	0.43 (.85)	0.26 (.58)	0.67 (1.15)	0.70 (.94)	F=2.3, p=.105
Life-time other trauma	1.31 (1.64)	0.85 (1.17)	1.54 (1.88)	2.93 (1.90)	F=22.9, p<.001
Mothers exposures
WTC attack-related trauma	1.07 (1.11)	1.52 (1.47)	2.08 (1.70)	2.00 (1.81)	F=2.6, p=.08
Life-time other trauma	1.25 (1.44)	1.07 (1.36)	0.88 (1.19)	2.64 (1.42)	F=18.51, p<.001
Mother’s impairment
Workb, N (%)	27 (27%)	8 (13.3)	8 (36.4%)	9 (61.1%)	X2(2)=17.3, p<.001
Household choresc, N (%)	15 (15%)	4 (6.7%)	4 (18.2%)	5 (35.7%)	X2(2)=11.5, p=.003
Friendsd, N (%)	14 (14%)	2 (3.3%)	4 (18.2%)	6 (44.4%)	X2(2)=19.8, p<.001
Fun & leisure activitiese, N (%)	15 (15%)	5 (8.3%)	4 (18.2%)	5 (35.7%)	X2(2)=7.0, p=.03
School workf, N (%)	2 (2%)	0	0	2 (14.3%)	X2(2)=9.0, p=.01
Familyg, N (%)	28 (28%)	5 (8.3%)	9 (40.9%)	11 (78.6%)	X2(2)=35.5, p<.001
Sex lifeh, N (%)	16 (16%)	2 (3.3%)	7 (31.8%)	5 (35.7%)	X2(2)=18.3, p<.001
General satisfaction, N (%)	38 (38%)	10 (16.7%)	13 (59.1%)	12 (85.7%)	X2(2)=31.5, p<.001
Overall problems, N (%)	15 (15%)	2 (3.3%)	5 (22.7%)	6 (44.4%)	X2(2)=19.7, p<.001
N. problem areas (in b-h)	1.55 (2.08)	.60 (1.15)	2.22 (2.20)	3.89 (2.25)	F=29.7, p<.001
Mother’s symptoms
PTSD	7.54 (9.94)	3.26 (4.35)	8.64 (9.57)	24.25 (10.32)	F=52.0, p<.001
depression	13.41 (10.33)	6.80 (3.97)	21.24 (7.87)	27.70 (9.01)	F=98.4, p<.001

NB: N may vary due to missing values.

^aMaternal education level was rated depending as follow. Holding a professional degree was coded as 1, having some post-graduate education as 2, a 4-year college degree as 3, a one to three years college education as 4, high school diploma as 5, completing a part of high-school education as 6, completing a middle-school education as 7, and less than a middle school education as 8.

Maternal psychopathology groups and functional impairment

With regard to maternal functional impairment, mothers with two disorders reported substantially higher rates of functional impairment across multiple domains including family relationships (78.6%), general life satisfaction (85.7%), work (61.1%), friends (44.4%), household chores and duties (35.7%), fun and leisure activities (35.7%), and sex life (35.7%). The average number of impairment endorsed across the seven domains was the highest (mean=3.89, sd=2.25) among mothers with two disorders, second highest (mean=2.22, sd=2.2) among mothers with one disorder, and lowest (mean=0.60, sd=1.15) among mothers with neither disorder (p<.001). As expected, there was also a significant difference in the level of PTSD (p<.001) and depression symptoms (p<.001) with two disorder group having the highest scores.

Maternal psychopathology to the WTC attacks

Degree of child exposure to high-intensity WTC attack-related events was positively associated with both maternal PTSD (p=.02) and maternal depression (p=.001). The mean number of high-intensity events experienced by the child was 1.2 (sd=1.4) for mothers with PTSD, and .6 (sd=.88) for mothers without PTSD. Similarly, the number of exposure events was 1.2 (sd=1·2) among children of mothers with depression, and .5 (sd=.89) among children of mothers without depression. Maternal exposure to attack related events was significantly associated with symptoms of depression (p=.01) and PTSD (p=.002). In our sample, 18.3% (n=17) mothers met PTSD criteria and 35.3% (n=36) for depression. Of 17 mothers with PTSD, 14 had co-morbid depression, and 3 mothers only PTSD. Of the 36 mothers with depression, 22 mothers had depression only. Thus, of the total of 102 mothers, 14 (13.7%) had two disorders, 26 (25.5%) had one, and 62 (60.8%) had neither disorder.

Rates of child behavioral problems reported by mothers and teachers as a function of maternal PTSD and depression.

Table 2 presents rates of clinically significant behavior problem. Except for somatic complaints, teachers generally identified more problems than mothers. However, when both teacher and mother reports on children were analyzed simultaneously using GEE with interaction terms between informants and maternal psychopathology, none of the interactions on child behavioral problem was significant, suggesting that mother’s PTSD and depression status did not bias child behavior ratings.

Table 2.

Rates of child behavioral problems reported by mothers and teachers by maternal PTSD and depression status

	Mother’s psychopathology
	Post-traumatic stress disorder
	Total (n=102)	Present (n=17)	Not present (n=85)			interactiona
Informant: behavior problem	Mean (SD)	Mean (SD)	Mean (SD)	t Test	p-value	p-value
Mother: emotionally reactive	12.75 (.34)	41.18 (.51)	7.06 (.26)	4.12	<.001
Teacher: emotionally reactive	18.63 (.39)	35.29 (.49)	15.29 (.36)	1.95	.05	.17
Mother: anxious/depressed	9.80 (.30)	23.53 (.44)	7.06 (.26)	2.11	.04
Teacher: anxious/depressed	17.64 (.38)	29.41 (.47)	15.29 (.36)	1.39	.17	.93
Mother: somatic complaints	10.89 (.31)	29.41 (.47)	7.14 (.26)	2.76	.007
Teacher: somatic complaints	7.80 (.27)	17.65 (.39)	5.88 (.24)	1.65	.10	.98
Mother: withdrawn behavior	8.82 (.29)	11.76 (.33)	8.24 (.28)	0.46	.64
Teacher: withdrawn behavior	12.75 (.34)	17.65 (.39)	11.76 (.32)	0.66	.51	.90
Mother: aggressive behavior	8.91 (.29)	23.53 (.44)	5.95 (.24)	2.36	.02
Teacher: aggressive behavior	17.64 (.38)	41.18 (.51)	12.94 (.34)	2.87	.005	.62
Mother: attention problems	9.90 (.30)	11.76 (.33)	9.52 (.30)	0.28	.78
Teacher: attention problems	13.73 (.35)	23.53 (.44)	11.76 (.32)	1.29	.20	.88
	Depression
	Total (n=102)	Present (n=36)	Not present (n=66)			interaction
Informant: behavior problem	Mean (SD)	Mean (SD)	Mean (SD)	t Test	p-value	p-value
Mother: emotionally reactive	12.75 (.34)	27.77 (.45)	4.54 (.21)	2.90	.001
Teacher: emotionally reactive	18.63 (.39)	27.77 (.45)	13.64 (.35)	1.76	.08	.15
Mother: anxious/depressed	9.80 (.30)	22.22 (.42)	3.03 (.17)	3.24	.002
Teacher: anxious/depressed	17.64 (.38)	25.00 (.44)	13.36 (.35)	1.44	.15	.23
Mother: somatic complaints	10.89 (.31)	22.86 (.43)	4.55 (.21)	2.89	.005
Teacher: somatic complaints	7.80 (.27)	11.11 (.32)	6.06 (.24)	0.90	.37	.35
Mother: withdrawn behavior	8.82 (.29)	13.89 (.35)	6.06 (.24)	1.33	.19
Teacher: withdrawn behavior	12.75 (.34)	19.44 (.40)	9.09 (.29)	1.50	.14	.67
Mother: aggressive behavior	8.91 (.29)	20.00 (.41)	3.30 (.17)	2.36	.02
Teacher: aggressive behavior	17.64 (.38)	36.11 (.49)	7.58 (.27)	3.83	.002	.55
Mother: attention problems	9.90 (.30)	17.14 (.38)	6.06 (.24)	1.79	.08
Teacher: attention problems	13.73 (.35)	25.00 (.44)	7.58 (.27)	2.49	.01	.58

^aInteraction between maternal psychopathology (either PTSD or depression) and informants (mother or teacher)

Rate of behavioral problems in children by number of maternal psychopathology risks

Taking both teacher’s and mother’s reports of child problem simultaneously into account, we then examined the children’s syndrome scores by number of maternal psychopathology risks. Table 3 shows the rate of clinically significant behavior problems by maternal psychopathology group. Children of mothers with two disorders, relative to children of mothers with neither disorder had substantially greater chance of having emotionally reactive (50% vs. 9.8%), aggressive behavior (40.9% vs. 5.1%), anxious-depressed (32.9% vs. 7.8%), somatic complaints (24.8% vs. 3%), withdrawn (20.8% vs. 8%), and attention problems (17.6% vs. 6.7%). The percentage of clinically significant behavior problems for children of mothers with one disorder generally fell between that of children of mothers with two disorders and that of children of mothers with neither disorder. Except for withdrawn behavior and attention problems, rates of problem behaviors in children were significantly different among the three maternal psychopathology groups and remained significant controlling for potential confounders.

Table 3.

Percentages (SE) of children with deviant CBCL syndrome scores according to whether the mother has neither, either, or both PTSD and depression.

	Maternal PTSD and/or depression						Adjusted			Adjusted
	Group 1	Group 2	Group 3	Overall difference			Overall differenceb			Overall differencec
Child Behavior problemsa	Neither	Either	Both
	% (SE)	% (SE)	% (SE)	X2	df	p	X2	df	p	X2	df	p
Total sample (n=102)	(n=62)	(n=26)	(n=14)
Emotionally Reactive	9.81 (.03)	15.52 (.06)	50.00 (.12)	10.57	2	0.005	9.73	2	0.008	8.81	2	0.01
Anxious Depressed	7.81 (.03)	17.71 (.06)	32·88 (.11)	6.4	2	0.04	7.56	2	0.023	7.51	2	0.02
Somatic complaints	2.95 (.02)	17.96 (.05)	24.79 (.11)	11.37	2	0.003	8.18	2	0.017	8.23	2	0.02
Withdrawn behavior	7.95 (.03)	11.29 (.04)	20.75 (.09)	2.01	2	0.37	3.73	2	0.16	1.82	2	0.41
Aggressive behavior	5.14 (.02)	15.87 (.06)	40.88 (.14)	10.01	2	0.007	12.03	2	0.002	12.64	2	0.002
Attention problems	6.70 (.03)	22.30 (.07)	17.60 (.09)	5.04	2	0.08	1.73	2	0.42	3.26	2	0.2

^aA score of 65 or more on each CBCL cluster was used to indicate behavioral problem symptoms. Depression is defined as scores above 16 on the CES-D scale; PTSD is defined as positive on all 6 symptom syndromes indicated by the PDS. When at least one of the cell counts was less than 5, Fisher’s exact test was used. Ns may vary due to missing values.

^bAdjusted for gender and age of the child, maternal education, time elapsed since the WTC attacks, level of child’s exposure to the WTC related trauma, and other trauma.

^cAdjusted for gender and age of the child, maternal education, time elapsed since the WTC attacks, level of child’s exposure to the WTC related trauma and other trauma, level of mother’s exposure to the WTC related trauma and other trauma.

Figure 1 shows the percentages of children who had clinically significant behavioral problems by maternal psychopathology group subdivided by gender. Boys of mothers with two disorders, compared to boys of mothers with neither disorder, exhibited strikingly high rates of emotionally reactive behavior (64.9% vs. 5.5%, p=.009) and somatic complaints (35.5% vs. 0%, p=.001), and aggressive behavior (67.7% vs. 4.6%, p=.001), whereas girls showed no difference among the three groups on those behavior problems. However, girls whose mothers had two disorders exhibited heightened anxious/depressed problems (39.6%), as compared to girls whose of mothers had one disorder (14%) and compared to the girls whose mothers had neither disorder (7.6%).

Figure 1.

Percentages of boys and girls with deviant CBCL syndrome scores among the three maternal psychopathology groups

Unadjusted and adjusted risk of behavioral problems by maternal psychopathology

Table 4 presents the unadjusted and adjusted relative risks. Children of mothers with two disorders demonstrated substantially increased risk for clinically significant behavioral problems. The increased risk remained statistically and clinically significant controlling for potential confounders, including age and gender of the child, SES, elapsed time to assessment, child trauma exposure (WTC and other-trauma), and maternal trauma exposure (WTC and other-trauma). The adjusted relative risks show an over 13-fold increased risk for aggressive behavior (p=.02), a 11-fold increased risk for emotionally reactive behavior (p=.03), an over 8-fold increased risk for somatic complaints (p=.02), and an over 7-fold increased risk for anxious-depressed (p=.005). Risk for attention problems were substantially attenuated after controlling for child’s and mother’s exposures to terrorism and trauma.

Table 4.

Relative risks for clinically significant behavioral problems in children of mothers with both PTSD & depression, either PTSD or depression, and neither PTSD nor depression.

Child behavior problemsa	N	Unadjusted Relative risk (95% CI); p-value	Adjustedc Relative risk (95% CI); p-value	Adjustedd Relative risk (95% CI); p-value	Adjustede Relative risk (95% CI); p-value
Emotionally reactive
Both	14	9.2 (3.3–11.0); .002	10.9 (8.4–11.2); .004	11.1 (4.5–11.3); .009	11.2 (2.1–11.3); .03
Either	26	5.7 (1.4–9.9); .02	8.8 (2.3–11.1); .009	8.6 (1.0–11.3); .05	8.5 (0.4–11.2); .16
Neither	62	1.0	1.0	1.0	1.0
Anxious/depressed
Both	14	7.4 (2.4–11.1); .002	7.5 (2.73–11.2); .003	7.4 (1.9–11.4); .009	7.6 (2.1–11.4); .005
Either	26	3.4 (.8–8.1); .08	3.6 (0.9–8.3); .07	3.4 (0.6–9.0); .16	3.8 (0.6–9.7); .13
Neither	62	1.0	1.0	1.0	1.0
Somatic complaints
Both	14	8.3 (1.8–17.4); .008	8.4 (1.8–19.3); .01	11.5 (1.7–22.6); .01	10.5 (1.6–22.2); .02
Either	26	1.6 (0.4–5.8); .54	1.5 (0.3–5.8); .58	1.3 (0.3–4.9); .70	1.1 (0.2–4.5); .91
Neither	62	1.0	1.0	1.0	1.0
Withdrawn behavior
Both	14	3.2 (0.8–7.9); .098	3.2 (0.8–7.9); .10	3.2 (0.7–8.9); .17	3.3 (0.7–8.7); .14
Either	26	2.8 (0.5–8.2); .23	2.8 (0.5–8.2); .23	2.4 (0.2–9.1); .41	3.1 (0.3–10.1); .31
Neither	62	1.0	1.0	1.0	1.0
Aggressive behavior
Both	14	14.6 (3.7–20.0); .002	15.2 (1.7–20.6); .02	14.6 (1.7–20.5); .02	13.0 (3.1–19.6); .02
Either	26	11.1 (1.9–19.3); .01	8.7 (1.7–20.1); .02	7.9 (2.2–20.1); .01	8.2 (1.3–19.9); .03
Neither	62	1.0	1.0	1.0	1.0
Attention problems
Both	14	4.3 (1.0–11.5); .05	4.4 (1.0–11.6); .05	0.7 (0.8–4.9); .74	1.0 (0.1–6.4); .97
Either	26	1.5 (0.3–5.6); .87	1.4 (0.2–5.7); .72	0.2 (0.2–2.1); .22	0.5 (0.1–4.6); .61
Neither	62	1.0	1.0	1.0	1.0

^aA score of 65 or more on each CBCL cluster was used to indicate behavior problem symptoms.

^bDepression is defined as scores above 16 on the CES-D; PTSD is defined as positive on all symptom clusters indicated by the PDS.

^cAdjusted for maternal education, gender and age of child of child, and time elapsed since the WTC attacks.

^dAdjusted for maternal education, gender and age of child, child’s exposure to the WTC attacks and other trauma, and time elapsed since the WTC attacks.

^eAdjusted for maternal education, gender and age of child, time elapsed since the WTC attacks, child’s exposure to the WTC attacks and other trauma, and mother’s exposure to the WTC attacks and other trauma.

N may vary due to missing value.

Odds ratio (OR) were converted into relative risk (RR) by using the formula below, where P₀ indicates the incidence of the outcome (i.e., each behavioral problem) in the control group.

$\text{RR}=\frac{\text{OR}}{(1-{\text{P}}_0)+({\text{P}}_0\times \text{OR})}$

COMMENTS

The present study makes a methodological contribution to research on the impact of maternal disorder on young children by bringing to bear sophisticated analytic techniques to take advantage of the use of multiple informants in child behavior to create more reliable and valid outcome measures. The remarkably increased risk for aggressive behavior problems, somatic complaints, and emotionally reactive behavior among children whose mothers had two disorders (PTSD and depression) is of particular public health concern. As hypothesized, children of mothers with two disorders exhibited strikingly greater risk for behavioral problems that index difficulties in child behavioral regulation.^{8, 49} Our finding of an association between the number of maternal disorders and degree of maternal functional impairment suggests a possible mechanism, parenting, through which child behavioral problems are affected. The impact of two disorders may reduce the ability of mothers to assist their very young children when they are most needed.

These results call for investigation of mother-child dyadic interaction patterns to identify specific behavioral deficits through which maternal functioning impacts the child’s emotional and behavioral regulation. For example, studies could examine the behavioral characteristics of children of mothers with co-morbid PTSD and depression using laboratory measures of emotional regulation in the face of threat. Involving mothers in interacting with children during threat challenges in the laboratory may help identify aspects of maternal functioning associated with co-morbid PTSD and depression, in the context of threat.

When our sample was subdivided by child gender, boys were more vulnerable than girls. Several case-control studies have found that girls relative to boys were at increased risk for posttraumatic problems or anxiety symptoms after exposures to hurricanes^{11, 52–54}, a dam collapse⁵², a flood⁵³, being taken hostage⁵⁴, parental psychopathology such as maternal depression,⁵⁵ and witnessing parent’s victimization by community violence⁵⁶. Other studies have found boys more vulnerable than girls for PTSD^57–58, anxiety⁵⁹, greater physiological reactions such as elevated cortisol response, and greater heart rate variability.⁶⁰ However, the large majority of studies have focused on school-aged children. Also, prior studies of gender differences examined child exposure to trauma without consideration of the indirect effects of maternal psychopathology. It is not clear whether the greater vulnerability of males in our study is explained by their developmental stage (preschool-age), by the type of trauma exposure (terrorism), or by their relationship with mothers. We interpret our gender findings with caution because subdividing maternal psychopathology groups by gender resulted in small group sizes.

Using multiple informants brings together ratings of behaviors across home and preschool environments, and offsets potential rating biases associated with each type of informant. To maximize multiple informant data, we made novel use of an analytic strategy (GEE) that reduces informant bias by taking account of correlations between multiple informant reports. The analytic techniques combining mother and teacher reports produce more reliable measures, and lead to more precise estimates of the associations between maternal psychopathology (the risk factor) and child behavioral problems.^26–27 Finally, we used staged statistical controls of common risk factors (age and gender of the child, SES, time elapsed since the WTC attacks, child exposure to terrorism and other-trauma, and mother’s exposure to terrorism and other-trauma) to more precisely examine the association of maternal psychopathology and children’s problems.

Study limitations

Future research should seek to assess maternal disorders more comprehensively using structured clinical interviews. Our measure of child exposure to other-trauma did not include exposure to sexual abuse and domestic violence. It is possible that as a result the count of other-trauma exposure in our sample was underestimated in some cases. To evaluate this, we examined data drawn from 68 dyads that participated in a second study phase during which they were asked by clinicians about child sexual abuse and domestic violence exposure. Only those children who reported exposure to other-trauma also reported sexual abuse or domestic violence⁶¹ suggesting that our results were not biased because we did not query these items. Finally, we did not have information on the level of disorder or the quality of functioning prior to the WTC attacks. Future studies examining the impact of maternal psychopathology on preschool children in the context of terrorism and disaster should use prospective longitudinal designs.

Clinical and policy implications

Our data indicate that the adverse effects of terrorism on very young children and their mothers can be persistent and long-lasting. Moreover, the number of maternal disorders appears to be strongly associated with preschool behavioral problems in the aftermath of terrorism exposure. We previously recommended screening of preschool children exposed to terrorism and disaster in the context of regular visits to their pediatricians. The present data suggest that mothers of young children should receive comprehensive screening for their psychological well-being and functioning as an additional means of mitigating the effects of terrorism-related maternal disorders on preschool children. This could occur in the context of disaster-recovery focused anticipatory guidance with mothers of very young children. Similarly, the deployment of interventions to support very young children might usefully include parent-focused information and skills training to support the capacity of parents to assist the recovery of young children exposed to traumatic events. Given the central role of pediatric primary care in the lives of very young children, we recommend consideration be given to co-location and integration of these post-disaster services for very young children in pediatric primary care.