Psychiatric Side Effects of Psychotropic Drugs(II): Clinical & Pathophysiological Implications

Yoon, Doh Joon

Abstract

The psychotropic effects of the original psychotropics currently in use, such as chlorpromazine, iproniazide, imipramine, lithium, and clozapine, have been applied to clinical practice through fortuitous discoveries of their psychiatric side effects (PSE). The etiopathophysiology of various psychiatric disorders have been deduced from the action mechanism of original psychotropics, and the designed drugs which selectively act on those neurotransmitters involved in the therapeutic effects of the original drugs are being developed as novel drugs. Psychiatric side effects cannot be considered to necessarily anti-therapeutic, as seen throughout the history of psychopharmacology. The clinical and pathophysiological significance of PSE deduced from their analyses according to the psychiatric symptoms manifested as PSEs are as follows: 1) PSEs are manifested according to the biological characteristics of the patient across diagnosis. This reflects the lack of biological basis in the current diagnostic system. 2) Psychotropics are important as in vivo pharmacological probes or challenges which, upon administration, allow for the biological characterization of the patient brain, i.e. pharmaco-biological typing of the patient may be performed based on the patient responses to the agent (both therapeutic and adverse effects). Such data may be of importance in subsequent prescription of the patient. 3) The hierarchy of a psychiatric disorder may be modified by drug administration, converting the disorder into that of a lower rank and thus into what is more easily treated. 4) A pharmacological approach, rather than a diagnosis-based one, is required. Consequently, more research into the still unknown psychotropic effects of each psychotropic is desired. In the process, clinically significant psychotropic effects currently undefined from the point of diagnosis-based approach may be discovered.