Nine-year psychiatric trajectories and substance use outcomes: an application of the group-based modeling approach

Abstract

This study identifies longitudinal psychiatric trajectories of 934 adult individuals entering chemical dependency treatment in a private, managed care health plan and examines the relationship of these trajectories with substance use (SU) outcomes. The authors apply a group-based modeling approach to identify trajectory groups based on repeated measures of psychiatric severity for 9 years and identify four distinct groups. Results of multivariate logistic generalized estimating equation models find an association between psychiatric trajectories and long-term SU. Older cohorts and life course measures of marital status and employment status as individuals changed over time are related to drug and some alcohol outcomes.

Figures

Figure 1

Average Psychiatric Addiction Severity Index (ASI) Scores From Baseline to 9 Years

Figure 2

Psychiatric Addiction Severity Index (ASI) Trajectories From 6 Months to 9 Years Posttreatment Entry SAS PROC TRAJ Model