Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant


Physician Assistant Studies

Department Chair

John Cavenagh, MBA, PhD, PA-C


Objective: The objective of this selective EBM review is to determine whether or not oral vitamin D supplementation is safe and effective for adults as therapy to improve symptoms associated with seasonal affective disorder (SAD) during wintertime.

Study Design: This review is based on three randomized controlled trials (RCTs) which were published in 2006, 2012, 2014. Two of the studies were double blind and placebo controlled. The studies evaluated the efficacy of oral vitamin D supplementation for improvement of seasonal affective disorder (SAD) symptoms. One of the studies also evaluated safety.

Data Sources: All articles used were published in English, in peer-reviewed journals and found in PubMed during the time period of November 2015 to February 2016.

Outcomes Measured: The outcomes measured were symptoms associated with SAD. One study measured subjective psychological well-being qualities (energy and vitality, social functioning, role functioning, and mental health), which were measured by Mean Component Score (MCS). The other two studies evaluated symptoms associated with SAD and perceived change from normal in: length of sleep, social activities, mood, weight, appetite, energy level by using Structured Interview Guide for the Hamilton Depression Rating Scale – Seasonal Affective Disorders (SIGH-SAD) and Global Seasonality Score (GSS) tools.

Results: None of the studies evaluated in this review had results to suggest that vitamin D supplementation is effective for improving symptoms associated with SAD. Dumville (2006) found no significant evidence (p = 0.262). Frandsen (2014) and Kjaergaard et al. (2012) both found no significant difference between placebo and vitamin D with p values of 0.7 and 0.734 respectively. Kjaergaard et al. (2012) also found there to be no significant difference in adverse events between the placebo and vitamin D groups.

Conclusions: This review suggests that although oral vitamin D supplementation is safe, it is not effective for adults as therapy to improve symptoms associated with SAD during wintertime.

Included in

Psychiatry Commons