I am puzzled by the statement:“Normally, one finds the gene and then defines the disease based on the cause.” Having been involved in the identification of the gene that causes spinocerebellar atrophy it was, like Huntington, known to be an identifiable, autosomal dominant disease long before the gene was discovered. All medical science depends on statistical probability. No-one is perfect in diagnosis or treatment but increased effort can lead to increased accuracy . Psychiatry seems to have forgotten the principle of differential diagnosis. It has been established several times that most of diagnosis depends on what the patient tells you that should lead to appropriate questioning and dialogue. What ever happened to the fifty-minute hour that at least allowed for the possibility of such interaction? Professor Robert Kendell was one of my instructors at the University of Edinburgh and was horrified by his own research into the time psychiatrists took to reach a diagnosis – less than ten minutes. To continue with causes let’s consider “Forty years on from Robins and Guze, what empirical evidence is there that disordered brain function is causally related a psychiatric diagnosis like ‘schizophrenia’?” One has to ask, what empirical evidence is there that the cause is not disordered brain function? As one of the thirty percent who hallucinate on Demerol I can assure you that I know what an hallucination is and I know the cause. It is repeatedly written that antipsychotics such as olanzapine increase weight. Yes, they do. But by what means? They increase appetite, that’s how. I have watched patients on olanzapine eat meals that would be too much for a lumberjack. We do know what substances control appetite, among them dopamine. We also know that most psychotropic drugs are lipophilic, heading straight for body fat where they hang around for a long time making withdrawal syndrome longer and more difficult. It is discouraging for those of us trying to improve the whole disaster of failed psychiatry and drug-soaked treatment to find an almost universal reluctance to open the mind and reject what has become a received wisdom that there is no such thing as mental illness. This dogma, just as the previous one, is going to help no-one.