Objectives: This quasi-experimental study investigates the effects of the first-ever home treatment (HT), equivalent to inpatient care, for individuals with dual diagnoses: severe alcohol and/or substance use disorder plus major psychiatric illness. Outcomes are compared to those of regular inpatient treatment (IT) of the same addiction service. The primary objective was to evaluate feasibility and safety of HT. Secondary outcomes measures included discontinuation of treatment and service utilization during the 12-month follow-up period as defined by the number of emergency department visits and hospitalization days.

Methods: Our Geneva model was introduced to meet local needs. In 2023, 39 individuals received home treatment (HT) for the first time, either in their own homes or in residential settings. They were retrospectively compared to a group of individuals who had undergone regular IT. Matching was based on age and gender. Allocation to IT or HT was determined by individual preferences as well as predefined inclusion and exclusion criteria following an evaluation interview. Electronic patient records were reviewed 1 year later to collect data on service use.

Results: The primary outcome criteria were met. Treatment withdrawal occurred among IT patients only. At 1-year follow-up, a clear difference in addiction-related hospital days emerged in favor of HT, with smaller but still favorable for HT differences for sequelae and somatic problems. At intake, the HT and IT groups differed regarding stimulant and opioid use, as well as in the presence of the exclusion criteria history of complicated withdrawal and suicidality, which were only present in the IT group. Health of the Nations Outcome Scale (HoNOS) scores at admission and discharge did not differ between groups. Sociodemographic factors showed small differences for partnership status and housing, more pronounced ones for employment, in favor of HT patients.

Conclusions: This first study on HT for dual-diagnosis patients suggests that such treatment is feasible and safe, as demonstrated for HT in general psychiatry, and may offer certain advantages over inpatient care. Key limitations include the lack of randomization, the retrospective design, limited statistical power, and the fact that data can currently only be compared with HT from general adult psychiatry.