The concept of disinhibitory agent is heterogeneous. If the disinhibitory property refers to inhibition in its clinical meaning, all psychotropic drugs can answer the denomination of disinhibitory agent when they are prescribed in some pathological entities. Traditionally this denomination refers to a few major tranquillizers, the antipsychotic action of which is linked to the improvement of the affective indifference and of the decrease of the psychomotor activity. However the pharmacokinetic data reveal that some potent sedative neuroleptics can become disinhibitors at high doses and some disinhibitory agents can become sedative substances at higher doses.