The Robert Koch Institute in Berlin (remember Koch’s Postulates?) earlier this year cancelled its research into Borna Disease Virus (BDV). That is really regrettable, because BDV, a neurotropic virus, may cause depression and bipolar disorder. BDV may be transmitted by blood transfusions; research on this is being carried out in Australia. There may even be an effective cure; an antiviral drug, amantadine sulfate, approved for use against the common flu.
Given the prevalence of depression and bipolar disorder, you should have thought that a decent randomized trial would have been carried out. A small trial would not cost more that a couple of hundred thousand dollars. But amantadine is a 30 year old drug, no longer covered by patents. There is practically no incentive for pharmaceutical firms to finance such a study. So far there has been none. Given the potential huge benefits and the low cost, that is a tragedy.
In the meantime, German and Austrian doctors are using amantadine and reportedly getting good results. However, we still need the solid evidence we would get from a well-designed randomized controlled trial.