Is there a common denominator for the antimanic effect of lithium and anticonvulsants?

Starting from the idea that different primary actions of carbamazepine, valproate and lithium might converge into a similar secondary mechanism of action, e.g. a modulation of the functioning of certain transmitter systems, a review of the literature was made on the effects of these and related substances on GABAergic, dopaminergic, cholinergic, noradrenergic and serotonergic transmission, in an attempt to find a common denominator. It was concluded that similarities of the effects of these drugs are most evident with respect to a reduction of dopaminergic transmission. Some similarities also exist with respect to GABAergic and, to a lesser degree, cholinergic transmission. The effects on noradrenergic and serotonergic transmission seem too disparate to be considered as a potential basis for the antimanic effects of these drugs.