title: Inhibitory deficits in euthymic bipolar disorder patients assessed in the human behavioral pattern monitor.
abstract: BACKGROUND
  Bipolar disorder (BD) is associated with inhibitory deficits characterized by a reduced ability to control inappropriate actions or thoughts. While aspects of inhibition such as exaggerated novelty-seeking and perseveration are quantified in rodent exploration of novel environments, similar models are rarely applied in humans. The human Behavioral Pattern Monitor (hBPM), a cross-species exploratory paradigm, has identified a pattern of impaired inhibitory function in manic BD participants, but this phenotype has not been examined across different BD phases. The objective of this study was to determine if euthymic BD individuals demonstrate inhibitory deficits in the hBPM, supporting disinhibition as an endophenotype for the disorder.
  
  
  METHODS
  25 euthymic BD outpatients and 51 healthy comparison subjects were assessed in the hBPM, where activity was recorded by a concealed videocamera and an ambulatory monitoring sensor.
  
  
  RESULTS
  Euthymic BD individuals, similar to manic subjects, demonstrated increased motor activity, greater interaction with novel objects, and more frequent perseverative behavior relative to comparison participants. The quantity of locomotion was also reduced in BD individuals treated with mood stabilizers compared to other patients.
  
  
  CONCLUSIONS
  Low sample size for treatment subgroups limits the evaluation of specific medication regimens.
  
  
  CONCLUSIONS
  Our results suggest that BD is distinguished by both trait- and state-dependent inhibitory deficits optimally assessed with sophisticated multivariate measures. These data support the use of the hBPM as a tool to elucidate the effects of BD across various illness states, facilitate the development of BD animal models, and advance our understanding of the neurobiology underlying the disorder.
authors.affiliation: Department of Psychiatry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA.
authors.forename: Brook L
authors.initials: BL
authors.lastname: Henry
authors.forename: Arpi
authors.initials: A
authors.lastname: Minassian
authors.forename: Virginie M
authors.initials: VM
authors.lastname: Patt
authors.forename: Jessica
authors.initials: J
authors.lastname: Hua
authors.forename: Jared W
authors.initials: JW
authors.lastname: Young
authors.forename: Mark A
authors.initials: MA
authors.lastname: Geyer
authors.forename: William
authors.initials: W
authors.lastname: Perry
mesh_terms: D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy / Q000523:psychology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents
keywords: Behavioral pattern monitor; Bipolar disorder; Euthymic; Exploration; Impulsivity; Inhibition