title: Seasonality and circadian preference in adult attention-deficit/hyperactivity disorder: clinical and neuropsychological correlates.
abstract: OBJECTIVE
  The objective of the study was to measure both seasonal mood change and circadian preference, and their clinical and neuropsychological correlates, in adults with ADHD during the fall/winter months.
  
  
  METHODS
  Twenty-nine adults with attention-deficit/hyperactivity disorder (ADHD) were assessed in the fall/winter season using self-report measures of ADHD, mood, seasonality, and circadian preference. Neuropsychological tests were also completed. Correlations between chronobiologic variables and clinical/neuropsychological measures were performed.
  
  
  RESULTS
  Consistent with prior work in adult ADHD, high rates of seasonal depression were reported in this sample. Based on the morningness-eveningness questionnaire, which assesses circadian preference 11 (40.7%, N = 27) subjects were designated as evening types and only 5 (18.5%) as morning types, a distribution highly discrepant with general population studies. Later circadian preference, independent of seasonality, was strongly correlated with both self-reported symptoms of ADHD and neuropsychological deficits, including impulsive responding and poor target discrimination. None of these findings was attributable to state depression.
  
  
  CONCLUSIONS
  In the fall/winter period, a mood-independent delay in circadian phase may contribute significantly to core pathology in many adults with ADHD. These findings establish a potential target for chronobiologic treatments such as light therapy in this complex population.
authors.affiliation: Mood and Anxiety Division of the Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, M5T 1R8 Canada. irybak@uwo.ca
authors.forename: Yuri E
authors.initials: YE
authors.lastname: Rybak
authors.forename: Heather E
authors.initials: HE
authors.lastname: McNeely
authors.forename: Bronwyn E
authors.initials: BE
authors.lastname: Mackenzie
authors.forename: Umesh R
authors.initials: UR
authors.lastname: Jain
authors.forename: Robert D
authors.initials: RD
authors.lastname: Levitan
mesh_terms: D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000523:psychology*; D002940:Circadian Rhythm; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000453:epidemiology; D001523:Mental Disorders / Q000453:epidemiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011446:Prospective Studies; D012044:Regression Analysis; D012621:Seasons; D011795:Surveys and Questionnaires