title: Seasonal Variations in the Severity of ADHD Symptoms in the Dutch General Population.
abstract: OBJECTIVE
  This is the first study to examine self-reported seasonal differences in the severity of ADHD symptoms in adults from the general population.
  
  
  METHODS
  Data were analyzed from N = 5,303 respondents participating in the second wave of the Netherlands Mental Health Survey and Incidence Study-2, a population-based study on mental health. ADHD symptoms were assessed using the Adult ADHD Self-Report Scale Screener. As indicators of the severity of ADHD symptoms, the total ADHD symptom score and inattention and hyperactivity subscale scores were examined.
  
  
  RESULTS
  Compared with participants who were assessed in autumn, total ADHD and inattention subscale scores were significantly higher among participants who were assessed in spring or summer; the hyperactivity subscale score was significantly higher in spring.
  
  
  CONCLUSIONS
  We found seasonal variations in the severity of ADHD symptoms, which was highest in those assessed in spring and summer. Researchers should be aware of this in the diagnostic process.
authors.affiliation: 1 PsyQ, Expertise Center Adult ADHD, The Hague, The Netherlands.
authors.forename: Suzan W N
authors.initials: SWN
authors.lastname: Vogel
authors.affiliation: 2 Netherlands Institute of Mental Health and Addiction (Trimbos Institute), Utrecht, The Netherlands.
authors.forename: Margreet L
authors.initials: ML
authors.lastname: Ten Have
authors.affiliation: 1 PsyQ, Expertise Center Adult ADHD, The Hague, The Netherlands.
authors.forename: Denise
authors.initials: D
authors.lastname: Bijlenga
authors.affiliation: 2 Netherlands Institute of Mental Health and Addiction (Trimbos Institute), Utrecht, The Netherlands.
authors.forename: Ron
authors.initials: R
authors.lastname: de Graaf
authors.affiliation: 3 VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Aartjan T F
authors.initials: ATF
authors.lastname: Beekman
authors.affiliation: 1 PsyQ, Expertise Center Adult ADHD, The Hague, The Netherlands.|3 VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: J J Sandra
authors.initials: JJS
authors.lastname: Kooij
mesh_terms: D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D008603:Mental Health; D009426:Netherlands / Q000453:epidemiology; D012621:Seasons; D057566:Self Report; D011795:Surveys and Questionnaires
keywords: ADHD symptom severity; population-based study; seasons