[Status of amine hypotheses in depressive disorders]

The biochemical effects of drugs modulating mood are the basis for still relevant hypotheses relating depressive disorders to dysfunctions of noradrenergic, serotonergic and/or cholinergic neurotransmission. The time course as well as the dose-effect-relationships point to the relevance for mood elevation of secondary adaptive processes rather than the direct actions of antidepressants. Direct evidence of dysfunctions sufficiently explaining the actual illness of the single individual has not been obtained at the level of transmitters, metabolites and receptors. Deficits of serotonergic transmission seem to be related to a personality dimension of poor impulse control closer than to nosological categories. This dimensional concept might also be valid for the relationships between cholinergic sensitivity and stress tolerance. Depression itself is possibly due to imbalances of multiple neuronal systems.