Abstract
People with attention-deficit/hyperactivity disorder (ADHD) experience higher rates of sleep difficulties coupled with greater circadian preference for eveningness. Emerging evidence suggests that symptoms of cognitive disengagement syndrome (CDS) may be associated with sleep difficulties and eveningness preference independently of ADHD symptoms. However, most studies have been conducted with children, adolescents, or college students. This study examined unique associations between ADHD and CDS symptom dimensions and sleep problems and circadian preference in a non-referred sample of adults. 106 adults (ages 18–75 years; Mage = 38.69 years) completed self-report assessments of ADHD and CDS symptoms, sleep quality and functioning, and circadian preference. ADHD inattentive (ADHD-IN), ADHD hyperactive-impulsive (ADHD-HI), and CDS symptoms evinced differential unique associations in regression analyses. Only ADHD-IN symptoms were uniquely associated with more frequent sleep medication use. Only ADHD-HI symptoms were uniquely associated with shorter sleep duration and greater nighttime sleep disturbance. Only CDS symptoms were uniquely associated with poorer sleep quality, longer sleep onset latency, greater daytime dysfunction, greater global sleep impairment, and greater eveningness preference. Findings support the importance of considering the role of CDS in sleep disturbance and circadian preference in adults with ADHD and point to the need for careful assessment of these dimensions in research and clinical care.
Keywords: circadian preference, sleep disturbance, sleep quality, attention-deficit hyperactivity disorder, cognitive disengagement syndrome, sluggish cognitive tempo
There is long-standing evidence that people with attention-deficit/hyperactivity disorder (ADHD) experience higher rates of sleep difficulties coupled with greater circadian preference for eveningness (Becker, 2020; Bondopadhyay et al., 2022). However, most studies have been conducted with children, with a recent meta-analysis identifying only 13 studies of sleep in adults with ADHD (Díaz-Román et al., 2018), with many of these studies examining college students (Becker, Luebbe, et al., 2023; Gau et al., 2007). As both ADHD symptoms and sleep/circadian function change across adulthood, it is important to examine ADHD dimensions of inattention (ADHD-IN) and hyperactivity-impulsivity (ADHD-HI) and sleep/circadian function in community-based samples spanning a wider age range.
Further, up to 50% of adults with ADHD experience co-occurring symptoms of cognitive disengagement syndrome (CDS; previously termed sluggish cognitive tempo), characterized by excessive daydreaming, mental confusion, and hypoactivity (Becker, Willcutt, et al., 2023). There is growing evidence of a link between CDS and sleep difficulties in youth with ADHD (Becker, Willcutt, et al., 2023), and emerging studies also suggest that CDS symptoms may be more consistently associated than ADHD symptoms with adults’ sleep difficulties (Becker et al., 2014; Fredrick et al., 2022; Langberg et al., 2014) and eveningness preference (Lunsford-Avery et al., 2021). Thus, it is possible that the often-cited association between sleep and circadian dysfunction is, at least in part, attributable to co-occurring, overlooked, CDS symptoms. However, very few studies have examined this possibility, and even fewer have examined non-college, non-referred samples.
Accordingly, the present study examined the unique associations between ADHD-IN, ADHD-HI, and CDS symptoms and sleep problems and circadian preference in a community sample of adults. Based on the handful of previous studies examining ADHD and CDS symptoms simultaneously in relation to sleep and circadian function in adults (Becker et al., 2014; Fredrick et al., 2022; Lunsford-Avery et al., 2021), we hypothesized that higher CDS symptoms would be uniquely associated with greater overall sleep problems, poorer sleep quality, greater daytime dysfunction, and a stronger preference for eveningness.
Method
Participants
106 U.S. adults (18–75 years; Mage = 38.69 years) participated in the study. Seventy-eight (73.6%) self-identified as women, 26 (24.5%) identified as men, and 2 participants (1.9%) identified as non-binary. Fourteen participants (13.21%) identified as Black or African-American, 12 (11.32%) identified as Asian, 2 (1.89%) identified as North African or Middle Eastern, 75 (70.75%) identified as White, 1 (0.94%) identified as Native American, 4 (3.77%) selected “Other,” and 3 participants (2.83%) preferred not to answer this question (categories sum to more than 100% because participants could select more than one response). Six (5.66%) participants identified as Hispanic/Latinx. Eleven participants (10.4%) reported having a diagnosis of ADHD and 7 of these participants reported taking medication for ADHD.
Measures
Barkley Adult ADHD Rating Scale-IV (BAARS; Barkley, 2011).
The BAARS is a self-report scale measuring ADHD and CDS symptoms within the past six months on a four-point scale (1 = Never or Rarely, 4 = Very Often). Scales for Inattentive, Hyperactive-Impulsive, and CDS symptoms (SCT scale) contain nine items each and had strong internal consistency in this sample (αs = .90, .80, and .88, respectively). Mean scores for these scales were used in the analyses.
Pittsburgh Sleep Quality Index (PSQI; Buysse et al., 1989).
The PSQI includes nine items that assess seven well-validated components of sleep (see Table 1) in addition to a total score. The PSQI is a frequently-used measure of sleep in adults, with strong psychometric properties (Buysse et al., 1989; Carpenter & Andrykowski, 1998).
Table 1.
Correlation coefficients among study variables
| ADHD-IN | ADHD-HI | CDS | Circadian Preference1 | Global Sleep Impairment | Daytime Dysfunction | Sleep Efficiency2 | Sleep Latency2 | Sleep Disturbance | Sleep Quality2 | Sleep Med Use |
Hours of Sleep2 | Age | Man3 | Nonbinary3 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ADHD-IN | --- | .46** | .73** | −.09 | .52** | .55** | .11 | .21* | .34** | .34** | .37** | .17* | −.04 | −.17* | −.18* |
| ADHD-HI | --- | --- | .49** | −.05 | .42** | .29** | .06 | .30** | .41** | .17* | .22* | .25** | −.21* | −0.13 | .09 |
| CDS | --- | --- | --- | −.26** | .59** | .64** | .21* | .36** | .31** | .42** | .21* | .23** | −.23** | −.22* | .17* |
| Age | −.04 | −.21* | −.23** | .40** | .01 | −.12 | −.06 | −.09 | .16* | −.01 | .07 | .12 | --- | --- | --- |
| Man3 | −.17* | −0.13 | −.22* | .13 | −.26** | −.10 | −.28** | −.15 | −.30** | −.12 | −.12 | −.02 | −.08 | --- | --- |
| Nonbinary3 | −.18* | 0.09 | .17* | .16* | −.04 | .24** | −.05 | −.06 | −.06 | −.04 | −.09 | −.08 | −.09 | --- | --- |
|
| |||||||||||||||
| M | 1.79 | 1.71 | 1.98 | 14.91 | 7.48 | 1.1 | 0.81 | 1.42 | 1.25 | 1.17 | 0.69 | 1.04 | 38.69 | --- | --- |
| SD | 0.63 | 0.51 | 0.62 | 3.95 | 3.34 | 0.82 | 0.87 | 1.02 | 0.55 | 0.64 | 1.11 | 0.94 | 14.66 | --- | --- |
Note. N = 106.
Higher scores indicate stronger morningness preference.
Higher scores indicate more dysfunction.
0 = No, 1 = Yes.
Correlation is significant at the 0.01 level (1-tailed, pre-registered).
Correlation is significant at the 0.05 level (1-tailed, pre-registered). ADHD-HI = attention-deficit/hyperactivity disorder hyperactivity-impulsivity symptoms. ADHD-IN = attention-deficit/hyperactivity disorder inattention symptoms. CDS = cognitive disengagement syndrome symptoms.
Reduced Morningness-Eveningness Questionnaire (rMEQ; Adan & Almirall, 1991).
The rMEQ was developed as a short form of the Morningness-Eveningness Questionnaire (Horne & Ostberg, 1976). It measures self-reported circadian preference using a five item scale (α = .66), and the total score was used in our analyses.
Procedure
The current study is a secondary analysis of baseline data collected as part of an ecological momentary assessment (EMA) study, which was approved by the institutional review board at the first author’s institution. Adult participants were recruited via email, social media advertisements, and word of mouth. They had to endorse using a smartphone daily, no plans to leave their current time zone for the duration of the study, and generally being awake from 9 AM to 10 PM (only two of 216 potential participants screened out for this reason). To obtain a broad age range, recruitment of participants ages 18–25 was capped at 25. During a one hour videoconferencing baseline visit, participants completed informed consent procedures, enrolled with the text message EMA survey system, and completed online baseline self-report scales. After participation, participants were compensated $20 for the baseline visit plus additional compensation based on number of EMA surveys completed.
Plan of Analysis and Departures from Pre-Registration
We pre-registered analyses on Open Science Framework after data collection but before conducting the analyses reported here – see https://osf.io/s9jur/?view_only=b2fa388c86574ddd9522cdd5c23e0a43). Masures, data, and analysis code are available on the project page associated with the pre-registration. We calculated bivariate Pearson correlation coefficients and evaluated them using one-tailed tests. We then conducted multiple linear regression analyses by simultaneously entering ADHD-IN, ADHD-HI, and CDS symptom dimensions as predictors of PSQI sleep subscales and rMEQ circadian preference, controlling for age and gender. Gender (woman, man, nonbinary) was dummy coded into two variables with women as the reference group.
In our pre-registration, we did not specify how many categories would constitute our gender coding and thus we made this decision after pre-registration. In the pre-registration, we stated in error that the rMEQ mean score would be used; however a total score must be used due to different scales of measurement across items. Finally, the pre-registered description of the regression analyses was not clear about entering ADHD-IN and ADHD-HI symptoms into the analyses separately, although that was our intention and the procedure we followed. Our pre-registration also described using sequential entry of symptom predictors rather than the simultaneous entry procedure described above. Since results did not substantially differ between the methods, we decided to use simultaneous entry for ease of description and interpretation.
Results
Bivariate correlation analyses indicated that higher ADHD-IN, ADHD-HI, and CDS symptoms were generally each significantly associated with poorer sleep across sleep functioning domains (rs = .17−.64, ps < .05); however, only CDS symptoms were associated with lower sleep efficiency (r = .21, p = .015). In addition, only higher CDS symptoms were significantly associated with greater eveningness preference (r = −.26, p = .003).
ADHD-IN, ADHD-HI, and CDS evinced differential unique associations in regression analyses. Only ADHD-IN symptoms were uniquely associated with more frequent sleep medication use (β = .44, p = .002). Only ADHD-HI symptoms were uniquely associated with shorter sleep duration (β = .23, p = .04) and greater nighttime sleep disturbance (e.g., bad dreams, feeling too hot/too cold; β = .35, p < .001). Only CDS symptoms were uniquely associated with poorer sleep quality (β = .41, p = .01), longer sleep onset latency (β = .38, p = .01), greater daytime dysfunction (β = .56, p < .001), and higher PSQI global sleep impairment (β = .43, p < .001). In addition, only CDS symptoms were uniquely associated with greater eveningness preference (β = −.30, p = .03).
Discussion
Findings indicate that ADHD and CDS symptoms are differentially associated with sleep and circadian functioning in adults, pointing to the need for careful assessment of these dimensions in research and clinical care settings for adults with ADHD and/or sleep difficulties and consideration of the potentially complex role of sleep problems and circadian preferences in ADHD-related impairment.
Moreover, CDS symptoms were most consistently associated with various sleep problems, and only CDS symptoms were associated with eveningness circadian preference in this sample. Our findings are consistent with the singular other study in a community sample of adults showing that CDS is more consistently associated than ADHD dimensions with sleep-related problems (Fredrick et al., 2022). Thus, the well-known association between ADHD and sleep/circadian problems may be at least in part attributable to co-occurring CDS symptoms which have been unexamined in most studies to date. This is clearly an important area for additional research, with a particular need for longitudinal and experimental studies that can test bidirectional and causal possibilities.
Several limitations are important to note. First, we relied solely on self-report rating scales of both sleep and circadian function; additional studies are needed using multi-informant, multi-method approaches. Second, our measure of circadian preference was brief and, perhaps as a result, had lower internal consistency. Third, participants had to endorse generally being awake between 9 a.m. and 10 p.m.; although only 2 of 216 potential participants screened out based on this criterion, it would be beneficial for future studies to include participants who may have extreme phase delay. Finally, the cross-sectional design precludes drawing causal or temporal inferences.
In conclusion, CDS symptoms and ADHD dimensions may have different associations with various domains of sleep and circadian function. As studies examining sleep in adults with ADHD advance, our findings join a limited body of research indicating the importance of simultaneously considering the role of co-occurring CDS symptoms.
Table 2.
Multiple regression results of ADHD and CDS symptoms in relation to circadian preference and sleep variables.
| ADHD-IN Symptoms | B | SE | β | Sig. |
|---|---|---|---|---|
| Circadian Preference (higher scores indicate greater morning preference) | ||||
| ADHD-IN Symptoms | .38 | .82 | .06 | .65 |
| ADHD-HI Symptoms | 1.13 | .77 | .15 | .15 |
| CDS Symptoms | −1.88 | .86 | −.30 | .03 |
| Global Sleep Impairment | ||||
| ADHD-IN Symptoms | .72 | .62 | .14 | .25 |
| ADHD-HI Symptoms | 1.13 | .58 | .17 | .05 |
| CDS Symptoms | 2.30 | .64 | .43 | <.001 |
| Daytime Dysfunction | ||||
| ADHD-IN Symptoms | .19 | .15 | .15 | .20 |
| ADHD-HI Symptoms | −.09 | .14 | −.06 | .53 |
| CDS Symptoms | .73 | .16 | .56 | <.001 |
| Sleep Efficiency | ||||
| ADHD-IN Symptoms | −.11 | .20 | −.08 | .60 |
| ADHD-HI Symptoms | −.09 | .19 | −.05 | .64 |
| CDS Symptoms | .34 | .21 | .24 | .11 |
| Sleep Latency | ||||
| ADHD-IN Symptoms | −.23 | .23 | −.14 | .31 |
| ADHD-HI Symptoms | .36 | .21 | .18 | .09 |
| CDS Symptoms | .63 | .24 | .38 | .01 |
| Sleep Disturbance | ||||
| ADHD-IN Symptoms | .10 | .11 | .11 | .39 |
| ADHD-HI Symptoms | .38 | .11 | .35 | <.001 |
| CDS Symptoms | .08 | .12 | .09 | .52 |
| Overall Sleep Quality | ||||
| ADHD-IN Symptoms | .09 | .14 | .09 | .52 |
| ADHD-HI Symptoms | −.07 | .13 | −.05 | .62 |
| CDS Symptoms | .42 | .15 | .41 | .01 |
| Frequency of Sleep Medication Use | ||||
| ADHD-IN Symptoms | .78 | .25 | .44 | .002 |
| ADHD-HI Symptoms | .23 | .23 | .11 | .33 |
| CDS Symptoms | −.25 | .26 | −.14 | .34 |
| Hours of Sleep per Night | ||||
| ADHD-IN Symptoms | −.10 | .21 | −.07 | .63 |
| ADHD-HI Symptoms | .41 | .20 | .23 | .04 |
| CDS Symptoms | .37 | .22 | .25 | .10 |
Note: Age and gender (two dummy coded variables) were included as covariates in all analyses. ADHD-HI = attention-deficit/hyperactivity disorder hyperactivity-impulsivity symptoms. ADHD-IN = attention-deficit/hyperactivity disorder inattention symptoms. CDS = cognitive disengagement syndrome symptoms.
Author Note:
Dr. Knouse is a clinical and research consultant for Get Inflow LTD and is a member of the CHADD professional advisory board. She receives book royalties from Taylor and Francis Publishers. She was supported by University of Richmond Faculty Fellow and Summer Research Fellowships during the completion of this work. Dr. Becker’s effort while preparing this manuscript was supported in part by grants from the National Institute of Mental Health (NIMH; R01MH122415) and the Institute of Education Sciences, U.S. Department of Education (IES; R305A200028). Dr. Becker discloses grant funding from the Institute of Education Sciences (IES), U.S. Department of Education; National Institute of Mental Health (NIMH); and Cincinnati Children’s Research Foundation (CCRF), and has received book honoraria from Guilford Press, editorial honoraria as Joint Editor of JCPP Advances, grant review panel honoraria from the IES, and educational seminar speaking fees and CE course royalties from J&K Seminars. The content is solely the responsibility of the authors.
Declaration of interests
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
Stephen P. Becker reports financial support was provided by National Institute of Mental Health.
Stephen P. Becker reports financial support was provided by US Department of Education.
Laura E. Knouse reports professional advisory board membership with Children and Adults with Attention-Deficit Hyperactivity Disorder (CHADD).
Laura E. Knouse reports stock options with Get Inflow LTD.
Laura E. Knouse reports book royalties from Taylor & Francis Publishers.
Stephen P. Becker reports grant funding and grant review panel honoraria from the U.S. Department of Education.
Stephen P. Becker reports grant funding from the Cincinnati Children’s Research Foundation.
Stephen P. Becker reports book honoraria from Guilford Press.
Stephen P. Becker reports editorial honoraria from JCPP Advances.
Stephen P. Becker reports educational seminar speaking fees and CE course royalties from J&K Seminars.
Footnotes
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Contributor Information
Laura E. Knouse, University of Richmond
Stephen P. Becker, University of Cincinnati College of Medicine and Cincinnati Children’s Hospital Medical Center
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