Substance use and psychiatric phenotypes of youth experiencing homelessness: A cluster analysis.

Background and objectives: Due to the complex interactions of psychopathology, psychosocial stressors, and risk behaviors, characterizing high-risk phenotypic groups of transitional-age youth experiencing homelessness (TAY-EH) for targeted interventions remains difficult. We aimed to uncover specific phenotypes of TAY-EH based upon psychiatric and substance use disorder (SUD) diagnoses, and to assess relationships between these phenotypes and negative outcomes including suicidality and high-risk behaviors.

Methods: Participants (N = 140; 57% male, 54% Black) were individuals aged 16-25 years accessing support at a psychosocial agency in the U.S. Northeast. Data were gathered via structured assessment. Cluster analysis identified sub-groups of TAY-EH with differing diagnostic patterns. Bivariate analyses examined associations between cluster membership and target outcomes.

Results: A four-cluster solution was identified. Cluster 1 (Co-occurring; N = 33) was characterized by high levels of comorbidity (i.e., major depressive disorder (MDD), SUD, and notable levels of other diagnoses). Clusters 2 (MDD alone; N = 47) and 3 (SUD alone; N = 18) were characterized by single diagnoses. Cluster 4 (None; N = 42) was characterized by low levels of psychopathology. Clusters differed significantly on several variables including suicidality, adverse childhood experiences, and social connectedness. Comorbid MDD and SUD were most strongly associated with high-risk behaviors and suicidality.

Discussion and conclusions: These results highlight the importance of diagnosis and targeted interventions for co-occurring MDD and SUD to address the crisis of early mortality and other negative outcomes among TAY-EH.

Scientific significance: This study is the first to identify specific high-risk psychiatric and psychosocial phenotypes among the highly complex group of TAY-EH based upon structured diagnostic assessments.