[Epidemiology, etiology and treatment of patients with psychosis and co-morbid substance use disorder].

Epidemiology, etiology and treatment of patients with psychosis and co-morbid substance use disorder Abstract. More than 25 years ago, when the research on the efficacy of treatments for patients with a comorbidity of psychosis and substance use disorder has been systematically started, some authors described the treatment of these patients as a "mission impossible". Approximately half of all individuals with schizophrenia develop substance use disorders in the course of their life; about one third of them a comorbid alcohol use disorder and about one quarter a comorbid substance use disorder with other addictive substances. There is no universally valid aetiology model to explain the relationship between psychosis and addiction. Contrary to expectations, the self-medication model was not empirically confirmed, while the psychological affect regulation model, the vulnerability-stress model of a specific sensitivity to addictive substances given a predisposition of psychosis, or the neurobiological common factor model of a dysfunction of dopamine regulation in the mesocorticolimbic reward system that predispose to primary substance use disorder found some empirical support. Research on the psychosocial-psychotherapeutic and pharmacological treatment of patients with psychosis and addiction are so heterogeneous in terms of characteristics of patients, disorders, treatments, settings and outcomes that hardly two comparable studies can be found. Thus, it is hardly possible to make scientifically based statements on the efficacy and effectiveness of therapies. Integrative treatment programs are promising, which combine psycho- and pharmacotherapeutic interventions for the treatment of psychotic and substance use disorders in a coherent manner and which can be flexibly adapted to the individual patient's needs. Such treatments are carried out at the same time, in the same setting and by the same treatment providers and practioners. Successful integrative treatment programs usually include motivational interventions, cognitive-behavioral interventions specific to schizophrenia and addiction, interventions that may reduce the substance use such as relapse prevention, contingency management and / or family interventions. These interventions are best combined with second-generation antipsychotics, if necessary with medication to reduce substance use. Although no "mission impossible" treating patients with psychosis and addiction remains a complex challenge for research and practice.