Anyone who has any contact with mental patients, old or young, or their families, or just visits a mental hospital or school for the retarded, is aware of the tremendous suffering caused by malfunctioning of the brain. The func­ tion of no other organ is so crucial for our everyday life, our proper func­ tioning, indeed our happiness, and no other illness causes as much anguish to patients or their families as mental illness. It is surprising and sad, therefore, how little effort has been devoted to research in this area; more so because such research is the only hope to ameliorate this suffering, or, to speak in the language of politics or economics, to decrease the enormous sums that we spend on trying to help our patients, with what is must generally be agreed are the most primitive and inadequate methods of treatment. Clearly, since functions of the brain are vital not only in illness, but in health, pathology is not the only area of concern to neurochemists, but it is an area that urgently needs neurochemical contributions. Progress in this field has been slower than in other areas of neurochemistry, and it seems that solutions in this field are very elusive. The reason for this is that the experimental approach is especially difficult in conditions specific for humans, or specific for complex behavior.