Date of Award

Summer 2020

Degree Type


Degree Name

Doctor of Philosophy (PhD)



Committee Chair

Stephanie Smith

Committee Chair School


Committee Member 2

Sara Jordan

Committee Member 2 School


Committee Member 3

Nora Charles

Committee Member 3 School


Committee Member 4

Theodore Tomeny


Caregivers (i.e., mothers and fathers) of youths with ID seem to be at a much higher risk of having symptoms of depression than caregivers of typically developing youths (Cantwell, Muldoon, & Gallagher, 2015; Giallo et al., 2015; Hu et al., 2010; Lee, 2013). A concurrent link has been found between parental locus of control (PLOC) and depression; however, there is a lack of support for a longitudinal association between these constructs among caregivers of youths with ID (Campis, Lyman, & Prentice-Dunn, 1986; Coyne & Thompson, 2011; Freed & Tompson, 2011; Lloyd & Hastings, 2009). Researchers have hypothesized that the lack of support for a prospective relationship between PLOC and parent depression may be due to changes in environmental factors such as parents’ stress and social support during the time period between measurements (Lloyd & Hastings, 2009). In the present study, it was predicted that parenting stress would mediate the relationship between PLOC and parent depression (simple mediation model) and parents’ perceived helpfulness of their social support would moderate the relationship between parenting stress and parent depression within this mediation model (moderated mediation model). The results supported the simple mediation model but did not support the moderated mediation model. Alternative models were examined to garner further confidence in the hypothesized simple mediation model. Results suggest bidirectionality of the indirect effect; however, the indirect effect of PLOC on depression was stronger than that of depression on PLOC. These findings suggest that fluctuations in parenting stress may explain why PLOC does not seem to predict depression over time. It is recommended that stress levels of these caregivers should be routinely monitored by iii their primary care physicians and they should be referred to mental health services if new stressors or early signs of depression emerge.