Question. I’m a medical student who is trying to find out exactly what the term “psychotropic drugs” includes. Does it cover marijuana and other street drugs, or is it only for mood-altering drugs (developed by pharmaceutical companies) without euphoric effects? What is the true definition?
Answer. Good question, but a bit like trying to nail spaghetti to a tree! The term “psychotropic” means, literally, “mind-turning” – from psyche (mind, soul) and tropos (turn). However, there is no exact definition of this term, since many agents, both natural and synthetic, prescribed and over-the counter, can affect psychic function, depending on the patient. For example, 25 mg of diphenhydramine – a common over-the-counter antihistamine – can actually provoke delirium in an elderly patient with Alzheimer’s Disease. For the average person this would almost never occur, and so we don’t ordinarily consider antihistamines to be “psychotropic drugs,” but this is rather arbitrary. Similarly, calcium channel blockers are not ordinarily thought of as psychotropic agents, and are not FDA-labeled for use in psychiatric disorders. Nevertheless, some data indicate that these drugs have effects on mood and behavior, and they are sometimes used to treat mania and anxiety or aggression.
If you want a semi-official definition, I’ll refer you to Dr. Frank Ayd’s excellent book, Lexicon of Psychiatry, Neurology, and the Neurosciences (1995, Williams & Wilkins). Ayd defines the term as a “drug that affects psychic function, behavior, or experience. Included are neuroleptics, antipsychotics, antidepressants, stimulants (such as methylphenidate) and antianxiety agents” (p. 545). While this definition does not mention marijuana and other street drugs, it does not necessarily exclude them. Sometimes the term “psychedelic” is used to describe drugs (like LSD) that induce hallucinations or sensory distortions, and the term “euphoriant” is used to describe drugs that elevate mood. But these are often dose-related properties. For example, amphetamines in low doses may improve mood (and even concentration), yet induce a paranoid psychosis at higher doses.
Now that I’ve muddied the waters for you, I will conclude by saying that most psychiatrists probably use the term “psychotropic” in the way Dr. Ayd has indicated, applying the term to agents whose intended purpose is to modify mood, cognition, or behavior in clinically useful ways.