Young SN (2009) J Psychiatry Neurosci. 34(1) 3.
No Abstract is available, but the full text of this paper can be freely accessed using the link above. The concluding paragraph only is reproduced here:
"Treatment of depression with vitamin D is an idea worth testing in carefully selected populations. This includes those with low vitamin D levels, especially the elderly, who have an increased incidence of low vitamin D, and patients with seasonal affective disorder who do not respond to light therapy. If there are patients in whom vitamin D is an effective antidepressant, this is likely to be one of the most cost-effective treatments in psychiatry, and one with negligible side effects."