Are novel treatments for brain disorders hiding in plain sight?

Psychiatric diseases are strongly influenced by genetics, but genetically guided treatments have been slow to develop, and precise molecular mechanisms remain mysterious. Although individual locations in the genome tend to not contribute powerfully to psychiatric disease incidence, genome-wide association studies (GWAS) have now successfully linked hundreds of specific genetic loci to psychiatric disorders [1-3]. Here, building upon results from well-powered GWAS of four phenotypes relevant to psychiatry, we motivate an exploratory workflow leading from GWAS screening, through causal testing in animal models using methods such as optogenetics, to new therapies in human beings. We focus on schizophrenia and the dopamine D2 receptor (DRD2), hot flashes and the neurokinin B receptor (TACR3), cigarette smoking and receptors bound by nicotine (CHRNA5, CHRNA3, CHRNB4), and alcohol use and enzymes that help to break down alcohol (ADH1B, ADH1C, ADH7). A single genomic locus may not powerfully determine disease at the level of the population, but the same locus may nevertheless represent a potent treatment target suitable for population-wide therapeutic approaches.