[Biological approach to depressive conditions: study of sleep (author's transl)].

Sleep disturbances are common in depressive states, and have been recently precised. Apart from insomnia, alterations of the organization of sleep and especially a shortening of paradoxical sleep latency, as well as modifications of slow wave sleep, have been reported. The main effect of classical antidepressant drugs is a marked decrease or a complete abolition of paradoxical sleep. However, some antidepressant drugs do not affect paradoxical sleep, and other drugs, devoid of antidepressant properties, depress markedly the production of paradoxical sleep. The investigation of the modifications of sleep in depressive states, as well as of the effect of antidepressant drugs, may contribute to a better understanding of the physiopathology of these diseases.