An imbalance between central cholinergic and adrenergic influences may affect mood disorders. Of 38 patients taking high doses of deanol, a putative acetylcholine precursor, eight developed changes in mood: five became depressed and three became hypomanic. A predisposition is suggested as seven of these eight patients had histories of affective symptoms. There was no relationship between the changes in dyskinesias and mood. These observations have both practical and heuristic implications for the management of patients and for further research into the pharmacology of affective disorders and deanol.