It has been suggested that depression is a disease of cholinergic dominance and since the beta-adrenergic blocking drug propranolol hydrochloride can cause depression, there arises the possibility that a beta-adrenergic stimulant could benefit the condition.
For ethical reasons, the adrenergic drug metaproterenol sulfate was combined with chlordiazepoxide hydrochloride and compared to placebo and chlordiazepoxide in a formal double-blind trial. However, the results did not show any advantage for the addition of metaproterenol either in respect of enhanced antidepressant effect or a reduced incidence, nature, or severity of side-effects.