Subtypes of clients with serious mental illness and co-occurring disorders: latent-class trajectory analysis.

OBJECTIVE: This study identified and characterized groups of clients who have serious mental illness and co-occurring substance use disorders.
METHODS: Substance abuse recovery of 177 clients with co-occurring disorders was followed for ten years with multiperspective ratings every six months. Latent-class trajectory analysis was used to identify subgroups; profile analysis was used to examine baseline risk factors and treatment participation.
RESULTS: Two ratings of substance abuse recovery-stage of treatment and abstinence-were highly concordant and identified the same four groups: early recovery, unstable recovery, late recovery, and no recovery. The early-recovery group was characterized by less severe substance use disorders at baseline and by use of clozapine. The unstable-recovery group was too small for statistical analyses. The late-recovery group was similar to the no-recovery group at baseline but participated more extensively in treatments, especially residential dual-diagnosis programs, during the first three years of follow-up.
CONCLUSIONS: Latent-class trajectory analysis based on ten-year trajectories of substance abuse recovery identified clinically meaningful groups among clients with serious mental illness and co-occurring substance use disorders. Profiles of the three most common groups suggest differential clinical approaches for each.