The efficacy of modified psychodynamic psychotherapy for patients with schizophrenia-spectrum disorders in Germany: a prospective, single-centre, assessor-blinded, parallel-group, randomised controlled trial.

Abstract

BACKGROUND: People with schizophrenia-spectrum disorders have difficulties in interpersonal functioning that remain insufficiently addressed by standard care. Despite long-standing clinical use, psychodynamic psychotherapy has little empirical support compared with other psychosocial treatments for people with schizophrenia-spectrum disorders. We evaluated the efficacy of Modified Psychodynamic Psychotherapy for Schizophrenia (MPP-S), a manualised treatment tailored to the interpersonal vulnerability characteristic of this population, plus treatment as usual (TAU), compared with TAU alone. METHODS: This prospective, single-centre, assessor-blinded, parallel-group, randomised controlled trial was conducted at the Psychiatric University Hospital of the Charité at St Hedwig Hospital in Berlin, Germany. Participants were outpatients aged 18-64 years who were diagnosed with schizophrenia or schizoaffective disorder and exclusion criteria included organic brain disorder, somatic illness affecting cerebral function, and current or past alcohol or illicit drug misuse requiring addiction-specific treatment. Participants were randomly assigned 1:1 in blocks of ten to MPP-S (minimum 30 sessions) plus TAU or TAU alone. Outcome assessors were masked, but participants and therapists were not. The primary outcome was psychosocial functioning, measured using the Mini International Classification of Functioning, Disability and Health Rating for Limitations of Activities and Participation in Psychological Disorders (Mini-ICF-APP) and evaluated at baseline and prespecified post-treatment (24 months) and follow-up (36 months) assessments. Analyses followed the intention-to-treat principle. Linear mixed models were used to analyse incomplete longitudinal data under a missing-at-random assumption. People with lived experience were not formally involved in the design, conduct, or reporting of this study. This trial was preregistered at ClinicalTrials.gov (NCT02576613) and is complete. FINDINGS: From Oct 12, 2015, to Dec 7, 2021, 130 participants (57 [44%] female and 73 [56%] male) were randomly assigned to either MPP-S plus TAU (n=65) or TAU alone (n=64). One participant withdrew consent to data analysis. Regarding the primary outcome of psychosocial functioning, linear mixed models showed significant group-by-time interactions favouring the intervention: estimated marginal means indicated adjusted between-group differences in Mini-ICF-APP scores of -3·45 (95% CI -5·51 to -1·40; p=0·0011) at 24 months and -4·07 (-6·19 to -1·94; p=0·0002) at 36 months. The frequency of adverse events was similar between groups. There were three serious adverse events: two participants died by suicide (one in the MPP-S plus TAU group who did not start psychotherapy and one in the TAU alone group) and one participant in the MPP-S plus TAU group was admitted to a forensic hospital. INTERPRETATION: MPP-S added to TAU could improve psychosocial functioning compared with TAU alone. Our findings suggest efficacy and possible long-term benefits of psychodynamic psychotherapy for schizophrenia-spectrum disorders and indicate its potential role alongside other psychotherapeutic and psychosocial treatments. FUNDING: Berlin Institute of Health, Deutsche Gesellschaft für Psychoanalyse, Psychotherapie, Psychosomatik und Tiefenpsychologie, International Psychoanalytic University Berlin, and Köhler-Stiftung.