Improving the treatment and remission of major depression in homeless people with severe mental illness: the multicentric French Housing First (FHF) program. French Housing First Study Group Running title: Major depression in homeless people with severe mental disorders

Abstract : Aims The objectives of the present study were to determine the rates and associated factors of (i) MDD, (ii) antidepressant prescription and (iii) MDD non-remission in homeless subjects with bipolar disorder (BD) or schizophrenia (SZ). Methods This multicenter study was conducted in 4 French cities. MDD was defined with the section L of the MINI. Unremitted MDD was defined by current antidepressant treatment and current MDD. Results 700 subjects, mean aged 38 years and 82.5% men were included: 55.4% were diagnosed with MDD but only 10.4% were administered antidepressants. Violent victimization in the past 6 months, alcohol use disorder and current substance abuse disorder were associated with increased rates of MDD. 71.2% antidepressant-treated subjects were unremitted. BD diagnosis and substance abuse disorder were found to be associated with increased risk of unremitted MDD. BD-MDD patients were found to be twice more frequently administered antidepressants than SZ-MDD ones, however the non-remission rates were higher in BD subjects compared to SZ. No antidepressant class and no specific antipsychotic or mood stabilizer has been associated with higher or lower rates of remitted MDD. Conclusion MDD seems to be highly prevalent, underdiagnosed and undertreated in BD and SZ homeless subjects. Beyond antidepressants, add-on strategies including complementary agents, lithium, lamotrigine/carbamazepine or anti-inflammatory drugs and the specific care of alcohol and substance use disorders may be recommended to improve the prognosis of this specific population in addition to other interventions including housing and resocialization. Violent victimization is also frequent and should be specifically prevented in this vulnerable population.