[Affective disorders and antidepressant drugs: Therapeutic innovations]

As it is the case in other psychiatric disorders, etiopathogenic hypotheses of depression have chiefly been shaped by the fortuitous discovery of antidepressive drugs. Reciprocally, these hypotheses have largely influenced later innovation in therapeutic drugs. In this paper, we aimed to study the development of pharmacological treatments through the different neurobiological and molecular models proposed in depressive illness through the last half-century. We first started by the monoaminergic hypothesis who postulates the existence of a deficit in monoamine transmission (norepinephrine and serotonine). We also discuss of drugs involving other neurotransmitters than the classic monoamines. If this monoaminergic hypothesis has long provided a first level of explanation for the action of antidepressant drugs, limitations have been pointed out. In the last 15 years, another model for the study of depression has clearly emanated: the stress model of depression. A possible reason for the success of this new hypothesis is its ability to provide a satisfying framework to experimental studies, in man and in animal. In this new background, numerous molecular and cellular events have been observed under the influence of stress, and these injuries appear to reverse with antidepressants. It thus seems that antidepressant agents have the ability to opposite the impact of stress through molecular actions, which directly or indirectly influence neuroplasticity.