Graduation Year


Document Type




Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Psychological and Social Foundations

Major Professor

Shannon Suldo, Ph.D.

Committee Member

John Ferron, Ph.D.

Committee Member

Sarah Kiefer, Ph.D.

Committee Member

Evan Dart, Ph.D.


affect, dual factor model, life satisfaction, mental health, psychopathology


In a dual-factor model, complete mental health entails average-to-high subjective well-being (SWB, happiness) and few internalizing and externalizing behaviors (IEB, mental illness). Although positive psychology interventions (PPIs) have been shown to increase middle school students’ SWB, more research is needed to understand how baseline IEB influences post-intervention outcomes. The current study examined the effect of baseline IEB on SWB outcomes for 122 middle school students who participated in the Well-Being Promotion Program (WBPP). The WBPP is a 10-week, small group, school-based PPI for students with low SWB, as identified from universal screening of life satisfaction. The dataset analyzed is part of an ongoing randomized control trial (RCT) evaluating the efficacy of the WBPP. The RCT will include data from three cohorts of schools; this study utilized data from the intervention group of the first cohort (three schools from two states). Results indicated approximately 76% of students self-reported elevated IEB at baseline, whereas parents and teachers identified approximately 53% and 16% of students with elevated IEB, respectively. Multilevel models indicated that more student-reported internalizing behaviors at baseline significantly predicted lower life satisfaction and positive affect, and higher negative affect. Student-reported externalizing behaviors were not significantly associated with any post-intervention indicators of SWB, but higher parent-reported externalizing behaviors significantly predicted lower positive affect. These findings increase researchers’ understanding of the relationship between IEB and PPI outcomes, and can help guide school-based practitioners when identifying students in need of mental health supports and selecting appropriate interventions.