title: Effects of emotional stimuli on time perception in manic and euthymic patients with bipolar disorder.
abstract: BACKGROUND
  Time perception, which plays a fundamental role in decision-making and the evaluation of the environment, is also influenced by emotions. Patients with bipolar disorder have impairments in emotional processing as well as interval timing. We investigated the effects of emotional stimuli on time estimation and reproduction in manic and euthymic bipolar patients compared with healthy controls.
  
  
  METHODS
  We recruited 22 manic bipolar patients, 24 euthymic bipolar patients and 24 healthy controls. Each subject performed time estimation and reproduction tasks using standardized affective pictures that were classified into 4 stimulus groups according to valence and level of arousal and presented for durations of 2, 4, and 6s. We analyzed temporal performance on these tasks using transformed data expressed as a proportion of the target period.
  
  
  RESULTS
  The interactions between arousal and valence were different in manic patients compared with euthymic patients and healthy controls in both time estimation and reproduction tasks. Manic patients showed no effect of positive valence low arousal stimuli in the time estimation task compared to euthymic patients and healthy controls. In the time reproduction task, the effect of emotional stimuli was reversed in manic patients compared to euthymic patients and healthy controls. Significant correlations between the severity of manic symptoms or illness severity and average temporal performance scores were found in manic patients.
  
  
  CONCLUSIONS
  Our results suggest that altered emotion-related time judgments may be a state-dependent phenomenon observed in manic patients only. This difference in time perception for emotional stimuli may be related to the underlying neurobiological mechanisms of the manic state.
authors.affiliation: Department of Psychiatry, Seoul National Hospital, Seoul, South Korea.
authors.forename: Vin
authors.initials: V
authors.lastname: Ryu
authors.affiliation: Department of Psychiatry, Myongji Hospital, Gyeonggi-do, South Korea.
authors.forename: Sodahm
authors.initials: S
authors.lastname: Kook
authors.affiliation: Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, Seoul National Hospital, Seoul, South Korea; Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, South Korea.
authors.forename: Kyooseob
authors.initials: K
authors.lastname: Ha
authors.affiliation: Department of Psychiatry, Yonsei University College of Medicine, Seoul, South Korea; Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, South Korea. Electronic address: chs0225@yuhs.ac.
authors.forename: Hyun-Sang
authors.initials: HS
authors.lastname: Cho
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001143:Arousal; D001714:Bipolar Disorder / Q000145:classification* / Q000503:physiopathology*; D004644:Emotions / Q000502:physiology*; D005260:Female; D006801:Humans; D007600:Judgment; D008297:Male; D008609:Mental Status Schedule; D010775:Photic Stimulation; D013223:Statistics as Topic; D013997:Time Factors; D013998:Time Perception / Q000502:physiology*; D064232:Visual Analog Scale; D055815:Young Adult
keywords: Arousal; Bipolar disorder; Emotion; Time perception; Valence