Little is known about guideline adherence of naturalistic antidepressant drug therapy in outpatients with major depressive disorder (MDD). The aim of the study was to analyze guideline adherence, especially regarding treatment length, treatment evaluation and medication change strategies. We investigated 889 patients with MDD who had been admitted for inpatient treatment and were enrolled in the early medication change trial (ClinicalTrials.gov NCT00974155). We investigated all patients at screening visit regarding previous outpatient drug treatment in the index episode, which was assessed by structured interviews. Demographic variables were obtained from patients and patients' records. 51.0% of the patients had received previous drug treatment in the index episode, 56.6% were females, and their mean age was 40.0 years. In the 153 patients who were pharmacologically treated at least 8 weeks, medication was not changed in 129 (84.3%) patients. Patients who had a medication change in their index episode (n = 24, 15.7%) waited 71.1 weeks (±110.4) for their treatment optimization. Only 5 of those 153 patients (3.3%) had a dose increase, whereas 132 patients (86.3%) had no dose adaption at all. Antidepressant blood levels were measured in 46 patients (30.1%). We conclude that a large proportion of patients with MDD is not treated in adherence to treatment guidelines recommending treatment evaluation (e.g. therapeutic drug monitoring) and treatment change after 4 to 8 weeks in non-responders. Earlier treatment optimization may prevent long-term suffering of patients and may avoid inpatient treatment.
