title: Clinical implications of loudness dependence of auditory evoked potentials in patients with atypical depression.
abstract: OBJECTIVE
  The loudness dependence of auditory evoked potentials (LDAEP) has been proposed as a useful biomarker of serotonin activity, and the LDAEP value is low in patients with melancholic depression. In this study, we evaluated LDAEP levels in patients with atypical depression.
  
  
  METHODS
  We recruited 53 patients with atypical depression and 68 patients with non-atypical depression. Subjects were evaluated by the Atypical Depression Diagnostic Scale (ADDS), Hamilton Rating Scale for Depression (HAMD), Hamilton Rating Scale for Anxiety (HAMA), Beck Scale for Suicidal Ideation (BSI), Behavioral Inhibition System and Behavioral Activation System (BIS/BAS) scales, and Hypomanic Personality Scale (HPS). To determine LDAEP, the peak-to-peak N1/P2 was measured at five stimulus intensities and the LDAEP was calculated as the linear-regression slope.
  
  
  RESULTS
  Patients with atypical depression had stronger LDAEP values and higher BAS and HPS scores than those with non-atypical depression. LDAEP showed a pattern of gradual decrease according to ADDS score hierarchy in patients with major depressive disorder. In the atypical depression group, LDAEP showed significant negative correlation with the BSI score and significant positive correlation with BAS score. In the non-atypical depression group, LDAEP did not show any significant correlations with the scores of psychological scales.
  
  
  CONCLUSIONS
  Our results suggest that there is a relatively deficient serotonergic activity in patients with atypical depression and that LDAEP reflects mood reactivity. The transient drop of serotonergic activity induced by mood vulnerability might contribute to suicidal tendencies in patients with atypical depression.
authors.affiliation: Department of Psychiatry, Inje University, Ilsan-Paik Hospital, Juhwa-ro 170, Ilsanseo-gu, Goyang, Republic of Korea; Clinical Emotion and Cognition Research Laboratory, Juhwa-ro 170, Ilsanseo-gu, Goyang, Republic of Korea.
authors.forename: Seung-Hwan
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Clinical Emotion and Cognition Research Laboratory, Juhwa-ro 170, Ilsanseo-gu, Goyang, Republic of Korea.
authors.forename: Young-Cheon
authors.initials: YC
authors.lastname: Park
authors.affiliation: Clinical Emotion and Cognition Research Laboratory, Juhwa-ro 170, Ilsanseo-gu, Goyang, Republic of Korea.
authors.forename: Sunkyung
authors.initials: S
authors.lastname: Yoon
authors.affiliation: Clinical Emotion and Cognition Research Laboratory, Juhwa-ro 170, Ilsanseo-gu, Goyang, Republic of Korea.
authors.forename: Jeong-In
authors.initials: JI
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, Soonchunhyang University of College of Medicine, 22, Daesagwan-gil, Yongsan-gu, Seoul, Republic of Korea. Electronic address: ha5hn@schmc.ac.kr.
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Hahn
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001921:Brain / Q000503:physiopathology; D003866:Depressive Disorder / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008144:Loudness Perception / Q000502:physiology*; D008297:Male; D011569:Psychiatric Status Rating Scales; D059020:Suicidal Ideation
keywords: Atypical depression; LDAEP; Major depression; Serotonin; Suicide