Mental Illness And Brain Disease

It has become common to say psychiatric illnesses are brain diseases. This reflects a conception of the mental as being biologically based, though it is also thought that thinking of psychiatric illness this way will reduce the stigma attached to psychiatric illness. If psychiatric illnesses are brain diseases, however, it is not clear why psychiatry should not collapse into neurology, and some argue for this course. Others try to maintain a distinction by saying that neurology deals with abnormalities of neural structure while psychiatry deals with specific abnormalities of neural functioning. It is not clear that neurologists would accept this division, nor that they should. I argue that if we take seriously the notion that psychiatric illnesses are mental illnesses we can draw a more defensible boundary between psychiatry and neurology. As mental illnesses, psychiatric illnesses must have symptoms that affect our mental capacities and that the sufferer is capable of being aware of, even if they are not always self-consciously aware of them. Neurological illnesses, such as stroke or multiple sclerosis, may be diagnosed even if they are silent, just as the person may not be aware of having high blood pressure or may suffer a silent myocardial infarction. It does not make sense to speak of panic disorder if the person has never had a panic attack, however, or of bipolar disorder in the absence of mood swings. This does not mean psychiatric illnesses are not biologically based. Mental illnesses are illnesses of persons, whereas other illnesses are illnesses of biological individuals.