ABSTRACT
OBJECTIVE: The current study examined whether (a) Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms were associated with dysregulation of stress-related mechanisms, and (b) whether ADHD symptoms interact with affective disorders in their association with dysregulated stress-related mechanisms. METHODS: Data were obtained from 2307 subjects participating in the Netherlands Study of Depression and Anxiety. Stress-related mechanisms were reflected by the following biomarkers: (1) hypothalamic-pituitary-adrenal axis indicators (salivary cortisol awakening curve, evening cortisol, cortisol suppression after a 0.5mg dexamethasone suppression test (DST)); (2) autonomic nervous system measures (heart rate, pre-ejection period, respiratory sinus arrhythmia); (3) inflammatory markers (C-reactive protein, interleukin-6, tumor necrosis factor-alpha); (4) brain-derived neurotrophic factor. ADHD symptoms were measured using Conners' Adult ADHD Rating Scale and used both dichotomous (High ADHD symptoms (yes/no)) and continuous (Inattentive symptoms, Hyperactive/Impulsive symptoms, and the ADHD index). RESULTS: Regression analyses showed associations between High ADHD symptoms, Inattentive symptoms, the ADHD index and a higher cortisol awakening curve, between Hyperactive/Impulsive symptoms and less cortisol suppression after DST, and between Inattentive symptoms and a longer pre-ejection period. However, the associations with the cortisol awakening curve disappeared after adjustment for depressive and anxiety disorders. No associations were observed between ADHD symptoms and inflammatory markers or BDNF. ADHD symptoms did not interact with affective disorders in dysregulation of stress-related mechanisms. CONCLUSION: Some associations were observed between ADHD symptoms, the HPA-axis, and the pre-ejection period, but these were mostly driven by depressive and anxiety disorders. This study found no evidence that ADHD symptomatology was associated with dysregulations in inflammatory markers and BDNF. Consequently, ADHD symptoms did not confer an added risk to the disturbances of stress-related mechanisms in an - already at-risk - population with affective disorders.
Subject(s)
Attention Deficit Disorder with Hyperactivity/physiopathology , Autonomic Nervous System/physiopathology , Hypothalamo-Hypophyseal System/physiopathology , Pituitary-Adrenal System/physiopathology , Stress, Psychological/physiopathology , Adolescent , Adult , Aged , Anxiety Disorders/blood , Anxiety Disorders/diagnosis , Anxiety Disorders/physiopathology , Attention/physiology , Attention Deficit Disorder with Hyperactivity/blood , Attention Deficit Disorder with Hyperactivity/diagnosis , Biomarkers , Brain-Derived Neurotrophic Factor/blood , C-Reactive Protein/metabolism , Depressive Disorder/blood , Depressive Disorder/diagnosis , Depressive Disorder/physiopathology , Female , Heart Rate/physiology , Humans , Hydrocortisone/analysis , Impulsive Behavior/physiology , Interleukin-6/blood , Male , Middle Aged , Netherlands , Respiratory Sinus Arrhythmia/physiology , Saliva/chemistry , Stress, Psychological/blood , Stress, Psychological/diagnosis , Symptom Assessment , Tumor Necrosis Factor-alpha/blood , Young AdultABSTRACT
BACKGROUND: Comorbid ADHD symptoms may partly account for circadian rhythm disturbances in depression and anxiety disorders. METHODS: Self-reported sleep characteristics of 2090 participants in the Netherlands Study of Depression and Anxiety were assessed using the Munich Chronotype Questionnaire. We defined 3 groups: healthy controls (HC), persons with lifetime depression and/or anxiety disorders (LDA), and those with both LDA and high ADHD symptoms (LDA+ADHD), using the Conner's Adult ADHD Rating Scale. RESULTS: Sleep characteristics were least favorable in the LDA+ADHD group. Important group differences between LDA+ADHD, LDA and HC were found for extremely late chronotype (12% vs. 5% vs. 3%; p<.001), sleep duration <6h (15% vs. 5% vs. 4%; p<.001), and for an indication of the Delayed Sleep Phase Syndrome (DSPS; 16% vs. 8% vs. 5%; p<.001). After adjustment for covariates, including depression and anxiety, presence of ADHD symptoms increased the odds ratio for late chronotype (OR=2.6; p=.003), indication of DSPS (OR=2.4; p=.002), and sleep duration <6h (OR=2.7; p=.007). LIMITATIONS: ADHD conceptually overlaps with symptom presentation of depression and anxiety. We used a cross-sectional study design, and used self reported sleep characteristics. CONCLUSIONS: High ADHD symptoms were associated with an increased rate of circadian rhythm sleep disturbances in an already at-risk population of people with depression and/or anxiety disorders. Circadian rhythm sleep disorders, as often seen in ADHD are not entirely due to any comorbid depression and/or anxiety disorder. Adequate treatment of such sleep problems is needed and may prevent serious health conditions in the long term.
