<a href="http:&#x2F;&#x2F;bjp.rcpsych.org&#x2F;content&#x2F;201&#x2F;5&#x2F;360.short" rel="nofollow">http:&#x2F;&#x2F;bjp.rcpsych.org&#x2F;content&#x2F;201&#x2F;5&#x2F;360.short</a><p>&quot;Participants with low 25(OH)D levels (n = 230) at baseline were more depressed (P&lt;0.05) than participants with high 25(OH)D levels (n = 114). In the intervention study no significant effect of high-dose vitamin D was found on depressive symptom scores when compared with placebo.&quot;<p>So it seems unlikely the cause is low vitamin D. Also, a sunlamp won&#x27;t increase your vitamin D. More likely it is the normalizing effect of sunlight on the body clock.<p>Also, no supplement is going to increase serotonin levels in your brain. Your brain already has sufficient raw materials to generate as much serotonin as is required. That&#x27;s just simplistic and wrong-headed nonsense, based on a lack of understanding about how the brain works.