I thought it was caused by a shortage of dopamine caused by a reduction in sun exposure. https://www.ncbi.nlm.nih.gov/pubmed/23434455 https://www.ncbi.nlm.nih.

I thought it was caused by a shortage of dopamine caused by a reduction in sun exposure. https://www.ncbi.nlm.nih.gov/pubmed/23434455 https://www.ncbi.nlm.nih.gov/pubmed/23434455