Finasteride
It has just been revealed that Donald Trump takes a drug called Finasteride. This medicine was originally developed, and still widely used, for treating benign enlarged prostate conditions, but was then found to be effective in preventing hair loss, which is apparently why Trump takes it. A couple of remarks about this. First, from the Washington Post: "a recent study demonstrated changes in the levels of certain steroids in cerebrospinal fluid of men taking finasteride for hair loss. These steroids have been shown to influence brain function, and their presence may help explain the profound psychological changes such as depression and suicidality that have been associated with finasteride use." And an enlarged list of potential side effects, from the Post Finasteride Syndrome Foundation: "The most common persistent side effects of finasteride are loss of libido, erectile dysfunction, depression, suicidal ideation, anxiety, panic attacks, Peyronie’s disease...