The results presented here, together with the literature data, support the noradrenergic hypothesis of depressive states, and especially the involvement of beta-adrenergic receptors: --In animals, beta stimulants have the same spectrum of activity as other antidepressants. --These effects of both classical antidepressants and beta-adrenergic stimulants are antagonized by beta blockers. --Chronic administration of antidepressants results in a decrease of beta receptors. --Salbutamol, a beta-adrenergic stimulant had, in depressed patients, a clear and rapid antidepressant effect.