Vitamin D, Depression and Self Efficac: The Results of a Longitudinal Study in Female College Students

Kwasky, Andrea, and Carla Groh

Problem Statement: 

Young adult women are at risk for developing depression, anxiety, and comorbid substance abuse.  When these disorders are left untreated, or undertreated, serious consequences can occur.  Efforts to identify factors that might be protective against depression are critical for improved health outcomes.  Self-efficacy is one such factor hypothesized to be a mediator of depression. 

Theoretical Framework:  Bandura’s self-efficacy theory provided the theoretical framework, positing that self-efficacy provides individuals with the motivation to initiate actions that can change and improve their circumstances.

Methods and Design:

A repeated measures correlational design with convenience sampling was used to address the research question:  Is there a relationship between vitamin D levels, depression scores, and coping self-efficacy scores in young adult women over three points in time.   Vitamin D was measured using serum 25(OH)D levels, with samples being obtained using dried blood spot testing.  Depression was measured using the Beck Depression Inventory II (BDI-II); and self-efficacy was measured using the Coping Self-Efficacy Scale (CSE).


78 college-aged women (M age 20; SD 1.6) completed all three data collection points. A significant relationship between BDI-II and CSE was noted at all three collection points (p=.000). Vitamin D levels decreased over the three points, with the differences being statistically significant (37.8, 30.8, 29.4, respectively; p=.000).  Scores on the BDI-II were in the non-depressed ranted at all three points.

Implications for Psychiatric-Mental Health Nursing Practice:

Implications include nursing strategies that increase a young women’s coping self-efficacy and proactive behaviors to attenuate the negative outcomes of depression.

Implications for Future Research:

A longitudinal research study that investigates the relationship between vitamin D, depression and self-efficacy in a sample of young women with depression or a history of depression would move this research endeavor forward.