title: Identifying predictive clinical characteristics of the treatment efficacy of mirtazapine monotherapy for major depressive disorder.
abstract: BACKGROUND
  Mirtazapine, which is classified as a noradrenergic and specific serotonergic antidepressant, is widely prescribed for the treatment of major depressive disorder. The potential predictive factors of the efficacy of mirtazapine and the tolerability based on the incidence of oversedation and jitteriness/anxiety syndrome were evaluated.
  
  
  METHODS
  Patients with major depressive disorder were retrospectively investigated. Study subjects comprised 68 patients with depression who received mirtazapine as an initial antidepressant at the Department of Psychiatry of the Tokyo Women's Medical University Hospital from September 2009 to March 2013. The efficacy of mirtazapine monotherapy was evaluated based on the Clinical Global Impression Improvement score. Clinical characteristics were compared between remission and nonremission groups to determine the factors predicting the efficacy. Moreover, discontinuation rates due to adverse effects, including oversedation and jitteriness/anxiety syndrome, were examined, and the effects of confounding factors were evaluated.
  
  
  RESULTS
  The remission rate of mirtazapine monotherapy was 36.8% among the 68 enrolled subjects. The mean final doses in the remission and nonremission groups were 27.6±13.5 mg and 26.0±14.1 mg, respectively, and there was no significant difference between them. Multiple logistic analyses revealed that the absence of guilt (odds ratio [OR] =0.15; 95% CI [1.66-37.24],P=0.006) and the presence of psychomotor retardation (OR =4.30; 95% CI [1.30-16.60],P=0.016) were significantly related to the efficacy of mirtazapine monotherapy. The discontinuation rates due to oversedation and jitteriness/anxiety syndrome were 13.2% and 11.8%, respectively. Age did not differ significantly between patients with or without oversedation or jitteriness/anxiety syndrome (P=0.078 andP=0.579, respectively).
  
  
  CONCLUSIONS
  The absence of guilt and the presence of psychomotor retardation may predict the efficacy of mirtazapine, and mirtazapine may be tolerable for all ages.
authors: Department of Psychiatry.
authors: Takahiro
authors: T
authors: Tsutsumi
authors: Department of Psychiatry; Support center for Women Health Care Professionals and Research.
authors: Hiroko
authors: H
authors: Sugawara
authors: Department of Psychiatry.
authors: Ryoko
authors: R
authors: Ito
authors: Department of Psychiatry.
authors: Mizuho
authors: M
authors: Asano
authors: Department of Research, Medical Research Institute, Tokyo Women's Medical University, Tokyo, Japan.
authors: Satoru
authors: S
authors: Shimizu
authors: Department of Psychiatry.
authors: Jun
authors: J
authors: Ishigooka
authors: Department of Psychiatry.
authors: Katsuji
authors: K
authors: Nishimura
keywords: anxiety syndrome; feelings of guilt; jitteriness; oversedation; psychomotor retardation