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Pleasure and pain
Pleasure-Seeking Behaviour
Avoiding Pain

Help A pharmacological classification of drags of abuse Assuétudes et pharmacie PSYCHOPHARMACOLOGIE DE LA TOXICOMANIE

The brain’s synapses can adapt to the chronic presence of a drug in various ways. For example, in some cases, to try to compensate for the sudden increase that a drug triggers in the concentration of a neurotransmitter, the synapses reduce the number of receptors for this neurotransmitter. In other cases, they simply make these receptors less sensitive to this neurotransmitter, so that it binds to them less efficiently. Both of these mechanisms are very common in chronic consumers of alcohol, opiates, nicotine, and benzodiazepines.

This tolerance can also involve other organs besides the brain. For example, in alcoholics, the liver becomes able to metabolize more alcohol, thus reducing the amount that reaches the brain.


A psychotropic is any substance that can modify a person’s psyche, causing changes in his or her perceptions, mood, consciousness, and so on.

Psychotropics can be classified in several different ways– for example, according to their chemical structure, or the mechanisms by which they act, or whether they are used recreationally or medically, or whether they are legal or illegal. But in addiction research, psychotropics are usually classified according to their pharmacological effects on people’s nervous systems, because these effects refer to a reality that is immediately perceptible.

In the 1970s, three major families of psychotropics were recognized on the basis of these effects: depressants, stimulants, and hallucinogens. Later classifications distinguished seven categories. The classification presented here comprises five categories: the three groups just mentioned, plus psychotherapeutic medications and steroids

(click on the name of each category to read a description of it and a list of the main drugs within it).

Depressants ---- Stimulants ---- Hallucinogens ---- Psychotherapeutic Medications ---- Steroids

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