04/24/2026
By Jinghua Liu

The Zuckerberg College of Health Sciences, Department of Public Health, invites you to attend a doctoral dissertation defense by Jinghua Liu on “Heterogeneity of Treatment Effects, Behavioral Mediators, and Trajectories in a Multicomponent Intervention for People Experiencing Homelessness with Co-occurring Disorders."

Candidate Name: Jinghua Liu
Degree: Sc.D.
Defense Date: Monday, May 11, 2026
Time: 1 to 3 p.m.
Location: O’Leary Library, room 512

Committee:

  • Advisor: Wenjun Li, Ph.D., Professor, Department Public Health, University of Massachusetts Lowell
  • Leland Ackerson, Sc.D., MPH, Associate Professor, Department Public Health, University of Massachusetts Lowell
  • Dan Berlowitz, MD, MPH, Professor, Department Public Health, University of Massachusetts Lowell
  • Yan Wang, Ph.D., Associate Professor, Department of Psychology, University of Massachusetts Lowell

Brief Abstract:
This dissertation examines a multicomponent intervention, Maintaining Independence and Sobriety through Systems Integration, Outreach, and Networking (MISSION), designed for people experiencing homelessness with co-occurring mental health and substance use disorders. Individuals in this population often face complex and overlapping challenges, leading to poor mental health outcomes and low engagement in treatment services. Although interventions such as MISSION have shown promise, less is known about whether their effects vary across subgroups, the mechanisms through which they operate, and how behavioral changes evolve over time.

This study has three primary aims. First, to examine heterogeneity of treatment effects (HTE) of the MISSION intervention by sociodemographic and clinical characteristics. Second, to investigate behavioral risk factors, including substance use and smoking, mediate the relationship between the intervention and outcomes. Third, to identify distinct trajectories of behavioral change over time and assess their associations with mental health outcomes and treatment engagement.
This study uses secondary data from the MISSION-NJ quasi-experimental study and the MASS-MISSION single-group study. Mixed-effects models were applied to evaluate HTE in continuous (BASIS scores) and binary (treatment engagement) outcomes. Mediation analyses were conducted using generalized structural equation modeling (GSEM). Group-based trajectory modeling was used to identify patterns of behavioral change. Results indicate that treatment effects vary across sociodemographic and clinical subgroups. Limited evidence was found for behavioral mediation. Distinct behavioral trajectories were identified and were significantly associated with changes in mental health outcomes and treatment engagement. These findings highlight the importance of considering subgroup differences and longitudinal behavioral patterns when evaluating complex interventions for vulnerable populations.