Chronic vs non-chronic depression in psychiatric inpatient care - Data from a large naturalistic multicenter trial

•Out of 954 depressed inpatients, 113 patients (11.8%) fulfilled criteria for chronic depression (CD), whereas 841 patients (88.2%) had non-chronic courses (NCD).•At baseline, clinician rated symptom burden between CD and NCD was comparable, but CD patients were younger at illness onset, reported more often a usage of benzodiazepines and psychotherapy, and showed higher rates of substance abuse, comorbid depressive personality disorder and showed a low degree of extraversion.•After inpatient treatment CD patients had a longer hospital stay, lower remission rates, increased rates of suicidal ideation as well as higher depression scores (HAMD, MADRS, BDI).•CD patients continued to obtain higher neuroticism scores and lower extraversion scores at discharge. Around 20% - 30% of depressed individuals experience a chronic form of depression lasting two or more years. This naturalistic study investigates the characteristics and the course of chronic depressed patients (CD) during standard antidepressant treatment in comparison to not chronically depressed (NCD) patients. Data of 954 patients were drawn from the prospective naturalistic, multicenter study of the German research network on depression, CD was met as classifier by 113 patients (11.8%), whereas 841 patients (88.2%) had non-chronic courses (NCD). CD was significantly associated with a low age at onset, use of benzodiazepines, psychotherapy at baseline, substance abuse, a depressive personality disorder and a low degree of extraversion. CD patients showed a longer hospital stay, lower remission rates, increased rates of suicidal ideation as well as higher depression scores at discharge. In addition, individuals with chronic depression continued to obtain higher neuroticism scores and lower extraversion scores at discharge. Results were assessed by a post-hoc analysis, based on prospectively collected data. CD patients have an inferior outcome in clinical measures as well as personality dimensions (i.e. low extraversion) compared to non-CD patients. These findings support the notion that CD patients entering a setting of standard psychiatric inpatient care will show less benefit compared to non-CD patients, and that this difference as such may be used as a stratifying marker for providing specialized psychiatric treatment with optimized pharmacological and psychotherapeutic protocols.