title: Normal levels of prepulse inhibition in the euthymic phase of bipolar disorder.
abstract: BACKGROUND
  Deficits in prepulse inhibition (PPI) of the acoustic startle response have been suggested as a potentially useful endophenotype for schizophrenia spectrum disorders and may explain certain symptoms and cognitive deficits observed in the psychoses. PPI deficits have also been found in mania, but it remains to be confirmed whether this dysfunction is present in the euthymic phase of bipolar disorder.
  
  
  METHODS
  Twenty-three adult patients with DSM-IV bipolar disorder were compared to 20 controls on tests of acoustic startle reactivity and PPI of the startle response. Sociodemographic and treatment variables were recorded and symptom scores assessed using the Hamilton Depression Inventory and the Young Mania Rating Scale.
  
  
  RESULTS
  Overall, the patient and control groups demonstrated similar levels of startle reactivity and PPI, although there was a trend for the inter-stimulus interval to differentially affect levels of PPI in the two groups.
  
  
  CONCLUSIONS
  In contrast to bipolar patients experiencing a manic episode, general levels of PPI were normal in this euthymic sample. Further studies are required to confirm this finding and to determine the mechanisms by which this potential disruption/normalization occurs. It is suggested that an examination of PPI in a high-risk group is required to fully discount dysfunctional PPI as a potentially useful endophenotype for bipolar disorder.
authors.affiliation: Department of Psychology, University of Ulster, Jordanstown Campus, Co. Antrim, UK. s.barrett@ulster.ac.uk
authors.forename: Suzanne Lucia
authors.initials: SL
authors.lastname: Barrett
authors.forename: Christopher
authors.initials: C
authors.lastname: Kelly
authors.forename: David Robert
authors.initials: DR
authors.lastname: Watson
authors.forename: Robert
authors.initials: R
authors.lastname: Bell
authors.forename: David John
authors.initials: DJ
authors.lastname: King
mesh_terms: D000161:Acoustic Stimulation; D001714:Bipolar Disorder / Q000175:diagnosis / Q000503:physiopathology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008875:Middle Aged; D013216:Reflex, Startle / Q000502:physiology*; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires