Dr. Davis been involved in depression research since the early formulations of the biogenic amine hypothesis of depression in 1965 in collaboration with Bunney. He was one of the first few researchers in psychopharmacology, and wrote one of the earliest texts in collaboration with Don Klein. He was the first to do meta-analysis in psychiatry in 1975, on maintenance treatment with antipsychotics, mood stabilizers, and antidepressants. At present, he is interested in the role of the omega-3 essential fatty acids in health and diseases. He continues to be active in meta-analysis of psychotropic drugs, including Omega-3 fatty acids in depression, and the role of fatty acids in the prevention of heart attacks and strokes.