title: Linear and non-linear analyses of Conner's Continuous Performance Test-II discriminate adult patients with attention deficit hyperactivity disorder from patients with mood and anxiety disorders.
abstract: BACKGROUND
  Attention Deficit Hyperactivity Disorder (ADHD) is a heterogeneous disorder. Therefore it is important to look for factors that can contribute to better diagnosis and classification of these patients. The aims of the study were to characterize adult psychiatric out-patients with a mixture of mood, anxiety and attentional problems using an objective neuropsychological test of attention combined with an assessment of mood instability.
  
  
  METHODS
  Newly referred patients (n = 99; aged 18-65 years) requiring diagnostic evaluation of ADHD, mood or anxiety disorders were recruited, and were given a comprehensive diagnostic evaluation including the self-report form of the cyclothymic temperament scale and Conner's Continuous Performance Test II (CPT-II). In addition to the traditional measures from this test we have extracted raw data and analysed time series using linear and non-linear mathematical methods.
  
  
  RESULTS
  Fifty patients fulfilled criteria for ADHD, while 49 did not, and were given other psychiatric diagnoses (clinical controls). When compared to the clinical controls the ADHD patients had more omission and commission errors, and higher reaction time variability. Analyses of response times showed higher values for skewness in the ADHD patients, and lower values for sample entropy and symbolic dynamics. Among the ADHD patients 59 % fulfilled criteria for a cyclothymic temperament, and this group had higher reaction time variability and lower scores on complexity than the group without this temperament.
  
  
  CONCLUSIONS
  The CPT-II is a useful instrument in the assessment of ADHD in adult patients. Additional information from this test was obtained by analyzing response times using linear and non-linear methods, and this showed that ADHD patients with a cyclothymic temperament were different from those without this temperament.
authors: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway. ole.fasmer@uib.no.|Department of Clinical Medicine, Section for Psychiatry, University of Bergen, Bergen, Norway. ole.fasmer@uib.no.|K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, Bergen, Norway. ole.fasmer@uib.no.|Department of Clinical Medicine, Section for Psychiatry, University of Bergen, Haukeland University Hospital, N-5021, Bergen, Norway. ole.fasmer@uib.no.
authors: Ole Bernt
authors: OB
authors: Fasmer
authors: , Madlamarkveien 2a, Hafrsfjord, Norway.
authors: Kristin
authors: K
authors: Mjeldheim
authors: , Lagårdsveien 91, Stavanger, Norway.
authors: Wenche
authors: W
authors: Førland
authors: Department of Clinical Psychology, University of Bergen, Bergen, Norway.|Centre for Research and Education in Forensic Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors: Anita L
authors: AL
authors: Hansen
authors: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.|Department of Neuroscience, the Norwegian University of Science and Technology, Trondheim, Norway.
authors: Vigdis Elin Giæver
authors: VE
authors: Syrstad
authors: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, Section for Psychiatry, University of Bergen, Bergen, Norway.|K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, Bergen, Norway.
authors: Ketil J
authors: KJ
authors: Oedegaard
authors: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors: Jan Øystein
authors: JØ
authors: Berle
mesh_terms: D000293:Adolescent; D000328:Adult; D001008:Anxiety Disorders / Q000150:complications / Q000175:diagnosis* / Q000523:psychology; D001288:Attention; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000523:psychology; D003527:Cyclothymic Disorder / Q000150:complications / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010045:Outpatients / Q000523:psychology; D013694:Temperament
keywords: ADHD; Complexity; Continuous performance test; Cyclothymic temperament; Variability