Shared characteristics in the clinical expression and pharmacological responses of mental disorders and their possible collective significance.

This paper points out the existence of, and enumerates, common characteristics spanning the clinical expression and pharmacological responses of most mental disorders. Central to the developed argument, the paper also points out an important overall property of brain function which normally insures a coordinated smoothness and synchronism across the expression of all the higher mental functions. Evidence from positron emission tomography studies supports the existence of a common initial structural abnormality which renders the brain vulnerable to a periodic loss of synchronism. This loss then expresses itself in a kind of 'psychic Parkinsonism', as shown in the characteristic, antithetical, oscillating format of the familiar cluster of symptoms of most mental disorders. The arguments are based on clinical observations and supported by a survey of the clinical and experimental literature.