Multi-method examination of cognitive disengagement syndrome and ADHD inattentive symptoms in relation to early adolescents’ academic functioning

Abstract

Cognitive disengagement syndrome (CDS), previously referred to as sluggish cognitive tempo, is a set of symptoms characterized by excessive daydreaming, mental fogginess, and slowed behavior/thinking. Studies examining the association between CDS and academic functioning have reported mixed findings and have relied upon limited measures of CDS, broad ratings of academic impairment, and/or focused only on elementary-aged children. The current study examined the relationship between CDS and academic functioning in adolescents using a comprehensive, multi-informant, multi-method design. Participants were 302 adolescents (M_age = 13.17 years; 44.7% female; 81.8% White; 52% with ADHD) recruited in the fall of their 8th grade. Above and beyond ADHD inattentive symptoms, CDS symptoms were related to poorer homework performance, lower math fluency, and lower daily academic motivation across multiple informants, and teacher-reported CDS symptoms were related to lower grades. Findings were not moderated by ADHD diagnosis, suggesting that associations between CDS and academic outcomes do not differ for adolescents with and without ADHD. Findings demonstrate that CDS symptoms are uniquely associated with daily academic difficulties as well as global indices of academic performance. These findings have implications for assessing and monitoring CDS symptoms in interventions aiming to improve the academic functioning in adolescents with and without ADHD.

There is clear evidence that symptoms of cognitive disengagement syndrome (CDS; previously termed sluggish cognitive tempo), including mental confusion, excessive daydreaming, and hypoactivity, are distinct from the inattentive symptoms of attention-deficit/hyperactivity disorder (ADHD-IN) as well as other psychopathology dimensions [1]. In considering the relation between CDS and functional outcomes, a meta-analysis found a moderate association between CDS symptoms and academic impairment in children (weighted r = 0.44) [2]. However, this association reflects bivariate correlations and does not take into account the role of ADHD-IN symptoms. Given that ADHD-IN symptoms are consistently and strongly associated with poorer academic functioning [3], it is important to evaluate whether CDS symptoms are independently associated with academic functioning above and beyond ADHD-IN symptoms. Indeed, a recent systematic review noted that when CDS and ADHD-IN symptoms were examined simultaneously, it was inconsistent as to whether CDS was uniquely associated with poorer academic functioning [4].

Several methodological factors also limit our understanding of the association between CDS and academic outcomes, including frequent reliance on global rating scale measures of academic impairment, non-comprehensive measures of CDS symptoms, small sample sizes, and use of a single informant for assessing CDS symptoms and/or academic functioning [4]. Further, the vast majority of studies examining CDS and academic functioning have been conducted with school-aged children, with only 9 of the 60 studies included in the systematic review (15%) focused on adolescents (i.e., sample age range between 10 and 17 years) [4]. Youth often experience new or heightened academic difficulties as they transition to adolescence [5, 6]. It is also unclear if CDS symptoms remain stable [7] or increase as children progress into adolescence [8], making this a key developmental period for evaluating and understanding the possible link between CDS symptoms and academic functioning.

As with the broader literature, findings are mixed in the nine studies that have examined CDS and academic functioning in adolescents. In the first study in this area involving 57 adolescents with ADHD, CDS symptoms were not uniquely associated with parent- or teacher-rated academic impairment, standardized achievement test scores, or parent-reported homework completion above and beyond ADHD and other covariates [9]. However, the only math achievement domain assessed focused on math skills under untimed conditions, and CDS symptoms may be expected to have a clearer or stronger association with performance under timed conditions (e.g., math fluency) [10, 11].

Two studies of adolescents diagnosed with ADHD found CDS symptoms to be significantly correlated with lower parent-reported homework performance [12] and greater parent-reported academic impairment [13], though both studies only examined bivariate correlations and did not examine whether associations remained present above and beyond other important variables such as ADHD-IN symptom severity. In addition, Burns and Becker [12] also included bivariate correlations with other academic measures, including standardized academic achievement testing, and found no significant associations. Another study of adolescents with ADHD found parent-reported but not adolescent-reported CDS symptoms to be significantly correlated with parent-reported homework problems, but once again unique associations controlling for ADHD-IN symptom severity were not examined [14]. Of note, the sample sizes for these two latter studies were both small (both Ns = 82).

Six studies to date have examined CDS and grades or grade point average (GPA) in adolescents. One study reported no association [12], another study reported an association that was no longer significant after controlling for ADHD-IN symptoms [15], and two studies reported a significant association with lower grades above and beyond ADHD-IN symptoms [16, 17]. Two other studies found only a slow task completion/low motivation factor to be associated with lower grades [18, 19], though it is important to note that the slow task completion/low motivation items used in these studies do not show discriminant validity from ADHD-IN items [20-22] and thus are not considered optimal items for assessing CDS [23]. Studies have also found the slow task completion/low motivation dimension to be most clearly associated with lower homework performance [19] and lower homework motivation [24].

The current study aims to build on and extend previous research in several ways. First, we used a multi-informant approach to assessing CDS, using parent, teacher, and adolescent ratings using rating scales that are ideal for assessing CDS as currently understood. Second, we used a multi-method approach to assess academic functioning, including academic achievement testing, daily ratings of teacher and adolescent reports of academic motivation/effort, parent- and teacher-reported homework performance, and GPA collected from school records. This approach overcomes rater/source biases and provides clinically relevant knowledge about the specific aspects of academic functioning where CDS is most clearly associated and perhaps detrimental. Third, our primary analyses examined CDS in relation to academic functioning over and above a robust measure of ADHD-IN symptoms, since the ADHD-IN symptom dimension is very clearly and strongly associated with poorer academic functioning [3]. We also included several other important variables as covariates, including medication, sex, and family income. Fourth, we examined our research questions in a large sample of adolescents with and without ADHD. As previous studies included either school-based samples or ADHD-diagnosed samples, our sampling approach allowed us for the first time to explore whether any associations between CDS and academic functioning were moderated by ADHD status. Given the mixed literature in this area, a priori hypotheses for each domain of academic functioning were not made. However, a recent systematic review concluded that there is growing evidence for an association between CDS symptoms and poorer academic performance among recent studies using CDS measures with strong psychometric properties [4]. Given our use of strong CDS measures in the current study, we expected CDS symptoms to be uniquely associated with at least some of our academic outcomes.

Methods

Participants

Participants were 302 adolescents between the ages 12–14 years (M = 13.17, SD = 0.40; 44.7% females). Parents identified adolescents’ race as White (81.8%), Multiracial (7.9%), Black (5.3%), Asian (4.5%), and American Indian/Alaskan (0.3%), and adolescents’ ethnicity as Hispanic/Latina/e/o (4.5%). Slightly more than half of participants (53%) had a reported family income of $100,000 or higher, 31.2% between $50,000 and $100,000, and 14.5% less than $50,000. Around 40% of adolescents were currently taking medication for ADHD or emotional problems (e.g., depression, anxiety), and/or a medication or supplement for sleep (e.g., prescribed medication or melatonin). For purposes of the larger study, recruitment targeted an approximately equal number of adolescents with and without ADHD (n = 162 diagnosed with DSM-5 ADHD; 120 with Inattentive Presentation and 42 with Combined Presentation). Further description of the sample and comparisons between the ADHD and comparison groups can be found in Table 1.

Table 1.

Sample characteristics and differences between adolescents with and without ADHD

	Total sample (N = 302)	ADHD group (n = 162)	Comparison group (n = 140)	Group differences
	M ± SD	M ± SD	M ± SD
Age	13.17 ± 0.40	13.17 ± 0.41	13.18 ± 0.40	t = 0.26, p = .80
Pubertal development
Female	3.07 ± 0.62	3.11 ± 0.57	3.05 ± 0.66	t = 0.60, p = .55
Male	2.34 ± 0.58	2.31 ± 0.56	2.39 ± 0.61	t = 0.86, p = .39
Primary household income ($USD)	93,073 ± 34,856	84,875 ± 35,864	102,500 ± 31,213	t = 4.56, p < .001
	n (%)	n (%)	N (%)
Female	135 (44.7)	57 (35.2)	78 (55.7)	X2 = 12.80, p < .001
Race				X2 = 9.17, p = .06
American Indian/Alaskan	1 (0.3)	1 (0.6)	0 (0)
Asian	14 (4.6)	4 (2.5)	10 (7.1)
Black	16 (5.3)	12 (7.4)	4 (2.9)
Multiracial	24 (7.9)	16 (9.9)	8 (5.7)
White	247 (81.8)	129 (79.6)	118 (84.3)
Hispanic/latinx	14 (4.6)	7 (4.3)	7 (5.0)	X2 = 0.08, p = .78
Highest maternal education
High school degree or less	14 (4.3)	10 (6.2)	4 (2.9)	X2 = 7.82, p = .05
Partial college/vocational	56 (18.5)	33 (20.4)	23 (16.4)
College graduate	126 (41.7)	73 (45.1)	53 (37.9)
Graduate/professional degree	106 (35.1)	46 (28.4)	60 (42.9)
Medication use
ADHD (any)	96 (31.8)	96 (59.3)	0 (0)	X2 = 121.63, p < .001
Methylphenidate	48 (15.9)	48 (29.6)	0 (0)	X2 = 49.32, p < .001
Amphetamineb	47 (15.6)	47 (29.0)	0 (0)	X2 = 48.10, p < .001
Non-stimulantc	20 (6.6)	20 (12.3)	0 (0)	X2 = 18.51, p < .001
Other Psychiatric (any)	29 (9.6)	22 (13.6)	7 (5)	X2 = 6.37, p = .01
Antidepressant	24 (7.9)	18 (11.1)	6 (4.3)	X2 = 4.78, p = .03
Antianxiety	2 (0.7)	1 (0.6)	1 (0.7)	X2 = 0.01, p = 1.00e
Antipsychotic	3 (1.0)	3 (1.9)	0 (0)	X2 = 2.62, p = .25b
Sleep (any)	32 (10.6)	23 (14.2)	9 (6.4)	X2 = 4.79, p = .03
Melatonin	31 (10.3)	22 (13.6)	9 (6.9)	X2 = 4.17, p = .04
Other sleep medication	1 (0.3)	1 (0.6)	0 (0)	X2 = 0.87, p = 1.00e
Other psychiatric diagnosesd	107 (35.4)	74 (45.7)	33 (23.6)	X2 = 16.04, p < .001
Any externalizing (ODD/CD)	41 (13.6)	35 (21.6)	6 (4.3)	X2 = 19.20, p < .001
Any anxiety	73 (24.2)	46 (28.4)	27 (19.3)	X2 = 3.40, p = .07
Any depression	24 (7.9)	16 (9.9)	8 (5.7)	X2 = 1.78, p = .18

ADHD attention-deficit/hyperactivity disorder, ODD/CD oppositional defiant disorder/conduct disorder, Any anxiety presence of generalized anxiety disorder, social phobia, obsessive–compulsive disorder, and/or posttraumatic stress disorder (PTSD). Any depression presence of major depression or dysthymia

^aADHD symptoms is the number of ADHD symptoms based on parent report during the diagnostic interview

^bIncludes amphetamine and mixed amphetamine salts

^cIncludes guanfacine, atomoxetine, and clonidine

^dPresence of comorbid mental health diagnosis based on parent or adolescent report (only parents were administered ODD and PTSD modules) during the diagnostic interview

^eSignificance based on Fisher’s exact test since at least one cell had an expected count less than 5

Procedures

This study was approved by the institutional review boards (IRBs) at Cincinnati Children’s Hospital Medical Center and Virginia Commonwealth University. Data in the current study were collected at the initial baseline visit of a broader study of adolescents with and without ADHD [25, 26]. Adolescents in eighth grade and their parents were recruited across two consecutive years. For the broader study from which the current data were drawn, potential families were recruited via distribution of a recruitment flyer and/or letter to all eighth-grade families by email, within an information packet, and/or at events attended by eighth-grade parents. Parents contacted the research staff in response to recruitment materials, and families meeting screening criteria via phone were invited to receive a comprehensive assessment, during which written informed consent and assent were obtained prior to adolescents and their parents being administered study measures. Inclusion criteria included: (a) enrollment in eighth grade, (b) estimated Full Scale IQ ≥ 80 on the Weschler Abbreviated Scale of Intelligence, Second Edition (WASI-II) [27], and (c) meeting criteria for either the ADHD or comparison group as defined below. Exclusion criteria included (a) past or current diagnoses per parent-report of autism spectrum disorders, bipolar disorder, or schizophrenia disorder and (b) previous diagnosis per parent-report of an organic sleep disorder.

ADHD diagnosis

ADHD diagnosis was established based on the parent version of the Children’s Interview for Psychiatric Syndromes (P-ChIPS) [28]. Adolescents in the ADHD group were required to meet criteria for either the ADHD combined presentation or predominantly inattentive presentation on the P-ChIPS. Specifically, participants were included in the ADHD group if parents reported ≥ 6 symptoms of inattention at clinically significant levels; presence of ADHD symptoms prior to age 12 years, presence of ADHD symptoms in two or more settings (e.g., home, school), evidence that symptoms contribute to home, academic, and/or social impairment; and symptoms of ADHD were not better explained by another mental disorder. Participants meeting criteria for ADHD predominantly hyperactive-impulsive presentation were not included (n = 2) given the low prevalence of this presentation in adolescence and ongoing concerns about its validity after early elementary school [3]. Adolescents were in the non-ADHD comparison group if the parent endorsed < 4 symptoms of ADHD in both domains (i.e., inattention, hyperactivity/impulsivity) on the P-ChIPS.

Measures

Child and adolescent behavior inventory (CABI)

Parents and teachers completed the CDS subscale of the CABI [29]. The CDS subscale includes 15 items (e.g., “gets lost in own thoughts,” “easily confused”) rated on a 6-point scale (0 = almost never, 5 = almost always) based on the adolescents’ behaviors over the past month. Previous studies provide strong support for the psychometrics of the CABI CDS subscale [12, 22, 30], and a recent systematic review found the CABI to be an optimal parent/teacher-report measure of CDS [23]. In the present study, mean scale scores were calculated for parent- and teacher-reported CDS (αs = 0.95 and 0.97, respectively).

Child concentration inventory, second edition (CCI-2)

Adolescent self-report of CDS was measured using the CCI-2 [31]. The CCI-2 items parallel the 15 items of the parent/teacher-reported CDS subscale (e.g., “I get lost in my own thoughts,” “I feel confused”). Items are rated on a four-point scale (0 = never to 3 = always), with higher scores indicating higher frequency of CDS symptoms. Previous research indicates reliability of CCI-2 scores and moderate correlations with parent- and teacher-reported CDS (rs = 0.29–0.36) [32]. For the current study, mean scale scores were calculated using 10 CDS items that showed discriminant validity from adolescents-reported ADHD-inattentive symptoms in the same sample as the current study [33]. In the present study, internal consistency was α = 0.93.

Vanderbilt ADHD diagnostic rating scale (VADRS)

Parent and teacher ratings of adolescents’ ADHD symptoms were assessed with the VADRS [34, 35]. The frequency of each symptom is rated on a four-point scale (0 = never, 3 = very often). Scores on the VADRS have demonstrated strong internal consistency, factor structure, and concurrent validity with other ADHD measures [34, 35]. In the present study, a mean item score was computed for inattention (parent-report α = 0.95, teacher-report α = 0.95) and hyperactivity/impulsivity (parent-report α = 0.90, teacher-report α = 0.92).

Homework performance questionnaire (HPQ)

The Homework Performance Questionnaire (HPQ) [36] was completed by parents and teachers. The parent version consists of 23 items rated on a four-point scale (0 = rarely/never, 1 = some of the time, 2 = most of the time, 3 = always/almost always). The teacher version consists of 17 items rated on a seven-point scale with corresponding percentages to indicate the amount of time a given behavior occurs (1 = never/rarely [0 = 10%], 7 = always/almost always [91–100%]). Items were worded in the positive so that 90–100% of the time indicates that the child does that behavior consistently well (e.g., student writes down homework assignments independently or manages homework time well). After reverse-scoring some items, a mean score was calculated such that for both parent and teacher versions such that higher scores indicate better homework performance in the past four weeks. The HPQ has demonstrated high internal consistency and convergent validity with other measures of homework [36]. In the present study, parent- and teacher-reported homework performance αs = 0.91 and 0.96, respectively.

Wechsler individual achievement test, third edition (WIAT-III)

The WIAT-III is a standardized achievement battery [37]. Age-based norms were used to derive standard scores for Basic Reading, Numerical Operations, and Math Fluency composites. Basic Reading is a composite score derived from Word Reading, a task measuring the speed and accuracy of decontextualized word recognition and Pseudoword Decoding, a task measuring the ability to decode nonsense words. Numerical Operations measures untimed, written math calculation skills in the following domains: basic skills, basic operations with integers, geometry, algebra, and calculus. Math Fluency is a composite score derived from three tasks measuring the speed and accuracy of a student’s math calculations in addition, subtraction, and multiplication separately in 60-s tasks.

Daily diary

Teachers and adolescents completed daily diaries over a two-week period. Diaries contained three items assessing academic motivation (“How motivated was this student [were you] to learn and try their [your] best today?”), effort (“How much effort did this student [you] put forth in their [your] classwork today?”), and quality of work (“How would you describe the quality of work this student [you] completed in school today?”). Each item was rated on a four-point scale (e.g., 1 = not at all motivated, 2 = motivated only a little, 3 = somewhat motivated, 4 = very motivated). Scores were calculated as an average of all three items over the two-week period.

Grade point average (GPA)

Final academic year report cards were obtained for all participants. All grades were converted into GPAs for core subject areas English/Language Arts, Social Studies, Math, Science) with a range from 0.0 to 4.0 (0.0 = F, 4.0 = A).

Covariates

Parents were administered an adaptation of the Services Use in Children and Adolescents—Parent Interview (SCAPI) [38] to assess current medication use (for ADHD, sleep [including melatonin], and/or an emotional/behavioral problem [e.g., anti-depressants]). Parents reported on family income and their child’s sex which were also used as covariates.

Analyses

First, bivariate correlations were conducted. Second, structural equation modeling (SEM) was used to understand the associations between CDS and academic functioning while accounting for ADHD inattentive symptoms. Analyses were modeled using Mplus Version 8 [39]. Separate models were run for each reporter (i.e., self, parent, teacher) of CDS. Given our primary research question to examine the contribution of CDS symptoms in relation to academic functioning above and beyond the well-established link between ADHD inattentive symptoms and academic functioning [3], and to decrease same reporter effects, we created an average of the parent- and teacher-reported ADHD inattentive symptom scores to create a composite variable of ADHD inattentive symptoms that was used as a predictor variable in each model. A mean score was used so that the findings can be interpreted based on the response choice options (e.g., a mean score of 2 = ADHD-IN symptoms on a whole are occurring “often”) whereas a total score does not provide information related to response anchors. All academic outcomes were included together in the same model for each informant of CDS symptoms. Covariates included medication, sex, and family income. We also explored group status (i.e., ADHD or comparison group) as a moderator. If group differences were found, group status would be included in subsequent analyses.

For all analyses, full information maximum likelihood (FIML) was used to address missing data [40]. All observed information is used to estimate parameters with this method and corrects for small sample bias by using the estimate of the sample means (Enders and Bandalos, [40]). FIML assumes data is missing at random (MAR), which means that any missing case can be related to variables in the model (Enders and Bandalos, [40]). Various fit indices were used to examine goodness of fit, including the comparative fix index (CFI; ideal study criterion ≥ 0.95; acceptable study criterion ≥ 0.80; adequate study criterion ≥ 0.70) and root mean square error of approximation (RMSEA; ideal study criterion ≤ 0.05; acceptable study criterion ≤ 0.08; adequate study criterion ≤ 0.10) [41, 42]. Standardized coefficients were used. Standardized coefficients can be used to gauge relative importance of paths and interpreted as r-values [43] with values 0.10–0.29 indicating a small effect, values 0.30–0.49 indicating a medium effect, and values greater than 0.50 indicating a large effect [44].

Results

All data had skewness and kurtosis values between −2 and 2 and variance inflation factors below 5. There were no significant outliers. Descriptive statistics and bivariate correlations among study variables are provided in Table 2. Generally, CDS ratings across self, parent, and teacher ratings were significantly associated with academic outcomes, with small-to-medium effects (rs = −0.12 to −0.43). Large-magnitude correlations were found between teacher-reported CDS symptoms and teacher-reported homework performance (r = −0.63) and teacher-reported daily academic effort/motivation (r = −0.54). There were some exceptions, however, as neither parent, teacher, nor adolescent self-report CDS ratings were significantly correlated with WIAT Basic Reading performance scores (rs = −0.05 to −0.09), and self-reported CDS symptoms were not significantly correlated with teacher-reported daily academic effort/motivation (r = −0.07). In contrast, ADHD-IN symptoms were significantly correlated with all academic outcome variables, with generally medium-to-large effects (rs = −0.26 to −0.59), except for a small association with WIAT Basic Reading (r = −0.15).

Table 2.

Bivariate correlations and descriptive statistics of study variables

Variable	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
1. SR CDS	–
2. PR CDS	0.33***	–
3. TR CDS	0.07	0.24***	–
4. ADHD-IN	0.29***	0.44***	0.44***	–
5. PR Homework	−0.29***	−0.50***	−0.28***	−0.55***	–
6. TR Homework	−0.15*	−0.28***	−0.63***	−0.59***	0.44***	–
7. Grades	−0.21***	−0.29***	−0.42***	−0.54***	0.57***	0.65***	–
8. WIAT Basic Reading	−0.05	−0.09	−0.05	−0.15*	0.16**	0.18**	0.27***	–
9. WIAT Num. Operations	−0.18**	−0.17**	−0.19**	−0.33***	0.38***	0.36***	0.54***	0.4***	–
10. WIAT Math Fluency	−0.32***	−0.26***	−0.17**	−0.35***	0.36***	0.31***	0.45***	0.39***	0.65***	–
11. SR Daily Motivation	−0.43***	−0.21***	−0.24***	−0.26***	0.31***	0.27***	0.38***	0.07	0.23***	0.27***	–
12. TR Daily Motivation	−0.07	−0.12*	−0.54***	−0.51***	0.4***	0.65***	0.59***	0.14*	0.33***	0.23***	.33***	–
13. Medication Use	0.22***	0.31***	0.24***	0.27***	−0.3***	−0.21**	−0.24***	−0.10	−0.18**	−0.20**	−0.13*	−0.16**	–
14. Sex	0.15*	−0.05	−0.07	−0.19**	0.19**	0.15*	0.20***	−0.04	0.04	−0.07	0.13*	0.21***	−0.06	–
15. Primary Income	−0.20***	−0.21***	−0.15*	−0.25***	0.33***	0.28***	0.34***	0.26***	0.28***	0.29***	0.07	0.16**	−0.22***	−0.020	–
M	0.86	0.88	0.87	0.97	2.04	5.66	3.12	103.90	102.48	96.21	3.12	2.36	0.39	0.45
SD	0.56	0.89	1.04	0.69	0.56	1.18	0.74	11.78	19.44	15.46	0.50	0.55	0.49	0.49

ADHD attention-deficit/hyperactivity disorder, CDS cognitive disengagement syndrome. HI hyperactivity/impulsivity, IN inattention (average of parent and teacher ratings). PR parent-report, SR adolescent self-report, TR teacher-report

^*p < .05.

^**p < .01.

^***p < .001

Unique associations of CDS and ADHD-IN symptoms with academic functioning

For all models, ADHD and comparison group were included together as ADHD status did not moderate any associations between CDS and academic functioning. All models had excellent fit statistics, except for the model with teacher-reported CDS which had adequate RMSEA (0.07); see Table 3. Despite this, all models were able to be interpreted and results are summarized below and in Table 3.

Table 3.

Structural equation model examining CDS and ADHD inattentive symptoms in relation to academic functioning

Variables	Self-reported CDS	Parent-reported CDS	Teacher-reported CDS	Parent/ teacher ADHD-IN†
PR homework performance	−0.15*	−0.32***	−0.04	−0.50***
TR homework performance	0.01	−0.01	−0.46***	−0.58***
GPA	−0.07	−0.09	−0.23***	−0.51***
WIAT basic reading	−0.01	−0.03	0.02	−0.14*
WIAT numerical operations	−0.10	−0.03	−0.04	−0.29***
WIAT math fluency	−0.24***	−0.13*	−0.01	−0.28***
Self-report daily motivation	−0.38***	−0.11	−0.14*	−0.15**
Teacher-report daily motivation	0.08	0.13*	−0.39***	−0.53***
Covariates
Medication	0.22***	−0.31***	0.22***	0.26***
Sex	0.16**	−0.04	−0.09	−0.17**
Family income	−0.20***	−0.21***	−0.15*	−0.29***

For all academic variables, higher scores indicate better/higher academic performance/functioning. Standardized effect sizes are reported for each model. ADHD-IN attention-deficit/hyperactivity disorder inattention CDS cognitive disengagement syndrome, GPA grade point average, PR parent-report, TR teacherreport, WIAT Wechsler Individual Achievement Test Third Edition

^†As described in Methods, a composite of parent- and teacher-reported ADHD-IN symptoms was used as a predictor variable in the models examining self-, parent-, and teacher-reported CDS in relation to academic functioning. The coefficients reported in the table are the range across the three models. See Supplemental Table S1 for the specific coefficient values the ADHD-IN symptom composite had in each model

Across all models (which differed only on the informant of CDS symptoms), higher levels of the composite of parent- and teacher-rated ADHD-IN symptoms were significantly uniquely associated with poorer academic functioning across all academic outcomes (see Table 3). Effects of ADHD-IN symptoms were moderate-to-strong for homework performance (βs = −0.38 to −0.58), moderate-to-strong for GPA (βs = −0.43 to −0.51), small-to-moderate for academic achievement scores (βs = −0.13 to −0.34), moderate-to-large for teacher-reported daily motivation (βs = −0.33 to −0.56), and small for adolescent self-reported daily motivation (βs = −0.15 to −0.21).

Homework performance

Unique associations for CDS symptoms in relation to homework performance differed by reporter. Parent- and teacher-reported CDS were significantly associated with poorer homework performance only within-informant (i.e., higher parent-reported CDS significantly uniquely associated with parent-report homework performance, β = −0.32, p < 0.001; higher teacher-reported CDS significantly uniquely associated with teacher-reported homework performance, β = −0.46, p < 0.001). Higher self-reported CDS was uniquely associated with lower parent-reported but not teacher-reported homework performance (βs = −0.15, p = 0.02 and 0.01, p = 0.60 respectively).

GPA

Only higher teacher-reported CDS was uniquely associated with lower GPA (β = −0.23, p < 0.001).

Academic achievement

No informant ratings of CDS were uniquely associated with either basic reading or numerical operations scores. Both self- and parent-reported CDS symptoms were uniquely associated with lower scores on math fluency (timed basic math test; βs = −0.24, p < 0.001 and −0.13, p = 0.03, respectively).

Daily academic motivation

Higher self- and teacher-reported CDS symptoms were uniquely associated with lower self-reported daily motivation (βs = −0.38, p < 0.001 and −0.14, p = 0.04 respectively). Higher teacher-reported CDS symptoms were also uniquely associated with lower teacher-reported daily motivation (β = −0.39, p < 0.001). In contrast, higher parent-reported CDS symptoms were uniquely positively associated with teacher-reported daily academic motivation (β = 0.13, p = 0.03). This unique association differs from the bivariate correlation analyses, as higher parent-reported CDS were negatively bivariately associated with teacher-reported daily academic motivation (r = −0.12, p = 0.04).

Discussion

The current study adds to our limited understanding of CDS in relation to academic functioning in adolescence by (1) using a comprehensive, multi-informant approach to measuring CDS and academic functioning, and (2) examining the role of CDS symptoms above and beyond a rigorous adjustment for ADHD-IN symptoms (i.e., combining across parent and teacher report). ADHD-IN symptoms were more consistently associated than CDS with poorer academic functioning, which aligns with a large body of research showing ADHD-IN to be strongly related to academic performance [3]. Indeed, our use of a composite measure of parent- and teacher-reported ADHD-IN symptoms was meant to reflect the gold-standard in ADHD diagnostic practice, and thus provide a stringent test of how CDS symptoms (rated by different informants) relate to academic functioning beyond ADHD symptoms alone.

General interpretation of study findings

Even with a stringent adjustment for ADHD-IN symptoms, CDS symptoms were associated with poorer functioning in certain academic domains. Broadly, CDS symptoms were related to poorer homework performance, lower math fluency, and lower daily academic motivation across multiple informants, whereas only teacher-reported CDS symptoms were related to lower GPA. Findings were not moderated by ADHD diagnosis, suggesting that associations between CDS and academics do not differ for adolescents with and without ADHD.

These results differ from the recent, comprehensive study of CDS and academic functioning which suggested widespread academic impairments related to CDS [10]. However, our study differs from the Becker et al. [10] study in several ways. First, Becker et al. [10] recruited students with and without clinically-elevated CDS, whereas the present study recruited students with and without ADHD. Thus, we may not have captured severe and/or impairing CDS as consistently in the current study. Second, whereas Becker et al. [10] controlled for teacher-reported ADHD-IN symptoms, in the current study we used a composite of parent- and teacher-reported ADHD-IN symptoms.

Third, Becker et al. [10] included younger children (i.e., 2nd-5th graders; ages 7–11 years). Although fewer studies have examined CDS-related academic impairments in adolescents, most had non-optimal measures of CDS for drawing conclusions regarding the relative contribution of ADHD vs. CDS and observed either few or no associations. It is possible that there are more consistent links between CDS and academic functioning in adolescents when CDS measures with strong psychometric support are used. Yet given that such measures were used in the present study and findings examining CDS in relation to academic functioning were inconsistent, it is also possible that CDS symptoms are more consistently or strongly associated with academic functioning in elementary school-aged children. We are not aware of any study that has directly tested this possibility. However, one study of 566 clinically-referred children found the association between CDS symptoms and processing speed to be moderated by age such that the association was stronger for children (ages 6–9 years) than in adolescents (ages 10–16) [45]. Slower processing speed is clearly associated with academic functioning [46, 47], including in youth with ADHD [48]. Slowed cognitive and motor processing may be one mechanism linking CDS to academic impairment [49], perhaps particularly so in younger children than in adolescents, though studies are needed to directly and rigorously test this possibility. Still, although findings of CDS being uniquely related to academic functioning were not as consistent as in Becker et al. [10], our results do indicate that CDS symptoms are uniquely related to poorer academic functioning in adolescents, though findings varied based on CDS informant and domain of academic functioning.

Interpretation of study findings by CDS informant and academic outcome

Higher parent- and teacher-reported CDS symptoms were each related to within-informant ratings of lower homework performance, and higher self-reported CDS symptoms were also associated with lower parent-reported homework performance. Prior work in adolescent samples has also observed parent-reported homework problems related to CDS symptoms [9, 12, 14], though most of this work has not accounted for ADHD-IN symptoms and did not also examine teacher-reported homework performance. As such, the current findings replicate and extend prior findings. Given that homework completion and performance involves a complex cycle of behavioral components both at home and at school [50], it is possible that parents may be better able to directly observe CDS-symptom impact on the behavioral components of homework that most interfere with performance (e.g., getting started, staying on task, completing homework in a timely fashion), whereas teachers may be most likely to only observe the end product (e.g., missing assignments, seemingly sloppy work). This may be particularly true for adolescents as homework demands typically increase [50].

Parent- and self-report also demonstrated convergence with our only significant relationship between CDS and standardized academic achievement, in which we observed higher parent- and self-reported CDS symptoms, but not teacher-reported CDS symptoms, to be associated with lower math fluency scores. This finding is consistent with the hypothesis that CDS would have clearer negative impact on performance under timed conditions, which would also explain why we did not observe a negative association for numerical operations since this test was not timed. The two prior studies that have examined academic achievement indices related to CDS in adolescents did not find significant associations between CDS symptoms and word reading, numerical operations [12], or composite scores of reading, math, and spelling [9]. Our findings, in conjunction to the limited prior research conducted in adolescent samples, highlight the need for further research and more comprehensive measurement of academic tasks to clarify these relations. First, more work is needed that examines possible differences regarding timed and untimed tasks. We only had timed and untimed tasks for math in the present study and it will be important to replicate our finding for math in other samples and in studies that include both timed and untimed tasks for other academic domains (e.g., reading, writing, spelling). Second, it will be important to include tasks that may be more likely negatively impacted by behaviors such as mind-wandering and daydreaming (e.g., reading comprehension), as these behaviors are constitutive of CDS [51, 52].

In contrast to multi-informant findings observed for homework performance and academic achievement, only higher teacher-reported CDS symptoms were related to lower GPA. Perhaps this is unsurprising given teachers manage and assign grades and may be most likely to have a comprehensive sense of academic strengths and weaknesses [53, 54]. Our findings are consistent with one prior study which has also observed CDS symptoms to be negatively related to teacher-reported grades independent of ADHD-IN symptoms [16]. Given that teacher-reported CDS was also related to teacher-reported homework performance in the current study, which is an important predictor of GPA [53, 54], our findings may suggest that teacher ratings of CDS may be most useful in gauging difficulties and impairments related to academic performance despite the agreement observed between parents and adolescents on homework performance. This is also consistent with previous research showing teacher-reported CDS symptoms to be more clearly associated than parent-reported CDS symptoms with cross-situational (home and school) academic impairment [55].

This reasoning may also explain why we also observed higher self-reported CDS symptoms to be related to lower self-reported daily academic motivation/effort, and higher teacher-reported CDS symptoms to be related to both lower teacher-reported and adolescent self-reported academic motivation/effort. Importantly, our study is the first that we are aware of to use a repeated measure of motivation in which informants are asked to rate level of motivation and effort specific to each day, rather than a global measure of motivation that would not be sensitive to fluctuations over time. We also found higher parent-reported CDS symptoms related to higher teacher-reported motivation, which is counter to our self- and teacher-reported CDS findings. Careful interpretation is warranted considering the bivariate correlation between parent-reported CDS symptoms and teacher-reported daily motivation was in the reverse direction and consistent with teacher- and self-reported CDS findings (i.e., higher parent-reported CDS symptoms were bivariately associated with lower teacher-reported academic motivation). However, taken together with our other findings, this may support the notion that teacher-reported CDS symptoms may be best-suited for gauging academic performance impairments related to CDS in real-world settings. Still, replication is needed before conclusions can be drawn.

Implications for assessment and treatment of CDS-related academic impairments

The current study findings highlight the need for both screening for CDS symptoms in the school environment and interventions to address any academic impairments that are related or specific to CDS symptoms. Only one study to date has examined whether existing school-based interventions move the needle on CDS symptoms among adolescents. Smith and Langberg [56] found that organizational skills and homework completion interventions for middle school-aged adolescents improved parent-reported CDS symptoms compared with a waitlist control condition, though this was not observed for self-reported CDS symptoms. Predictors of parent-reported improvement included improvements in behavioral and metacognitive executive functioning, as well as improvements in inattention [56], which support the notion that existing and domain-general interventions may also improve academic impairments that are uniquely related to CDS. However, more tailored interventions may also be needed or at least beneficial, especially given a lack of robust improvement to CDS symptoms reported by the adolescents themselves [56]. A recent study found that CDS had a detrimental effect on academic achievement through a decrease in learning engagement [17], thus, academic motivators and enablers may be a needed academic intervention to increase learning engagement.

Mindfulness-based interventions may be an important avenue for future intervention research [52]. Mindfulness has shown promise in improving attentional concerns in adults and adolescents with ADHD and appears to improve working memory capacity and reading comprehension [57]. Trait mindfulness has also been shown to be related to academic persistence and resistance to boredom [58]. Mindfulness may be of particular benefit to individuals with CDS, as a growing body of research suggests that mind-wandering, one of the targets of mindfulness interventions defined by internally-focused distraction, may be more consistently or strongly associated with CDS symptoms than with ADHD symptoms [51, 59]. Although more research is needed in this area, these findings point to the possible academic utility of mindfulness-based interventions for CDS.

Limitations

The present study findings should be considered with respect to several limitations. First, the cross-sectional design of our study precludes causal interpretation or establishing temporal relationships. Second, our measures of standardized academic achievement were limited and it will be important for future studies to include other domains that have been hypothesized to be impacted by CDS (e.g., reading comprehension). As Wang and colleagues [17] found, when accounting for ADHD symptoms, the effect between CDS and academic achievement was nonsignificant, however, this finding was suppressed by learning engagement. Future work should include academic enablers like learning engagement and motivation when examining CDS and academic achievement. Also, although CDS scores do not generally differ across the full range of intelligence [60], it nevertheless remains important to examine the unique relation between CDS and academic functioning when also accounting for IQ (e.g., [61]), as well as to examine this association in children with a full range of IQ scores. Fourth, our sample is largely comprised of White adolescents from higher-income families, and as these rates are higher than the U.S. population the findings may not generalize to more representative samples. This is particularly important for youth with ADHD, as there are clear health disparities for Asian, Black, Indigenous, and/or Latina/e/o youth with ADHD when compared to White peers that likely affect academic functioning [62]. Finally, we focused on adolescents but had a sample with a narrow age range (ages 12–14, all in 8th grade). Our findings cannot be assumed to generalize to older adolescents, and this is another important area for future research, particularly as academic demands and independence increase as students progress through secondary school and, for many, into college.

Conclusions

The present study examined academic outcomes related to CDS that are independent of ADHD-IN symptoms among adolescents with and without ADHD using multiple informants and measures of CDS and academic outcomes. As expected, ADHD-IN symptoms measured with a composite of parent- and teacher-report were related to poorer functioning on all academic indices. In addition, findings indicate that CDS symptoms contribute unique variance in relation to academic functioning in adolescents, and while findings varied somewhat across CDS informant and academic domains examined, findings were most consistent in demonstrating CDS symptoms as uniquely related to poorer homework performance, lower math fluency, and lower daily academic motivation above and beyond ADHD-IN symptoms.

Supplementary Material

Supplementary Information The online version contains supplementary material available at https://doi.org/10.1007/s00787-023-02311-8.

Data availability

Data are available from the corresponding author upon reasonable request and execution of a data use agreement.