Possible use of amantadine in depression.

Amantadine, originally used in the treatment and prophylaxis of influenza infection, has also proved beneficial in drug-induced Parkinsonism, Parkinson's disease, traumatic head injury, dementia, multiple sclerosis and cocaine withdrawal. Amantadine appears to act through several pharmacological mechanisms, none of which has been identified as the one chief mode of action. It is a dopaminergic, noradrenergic and serotonergic substance, blocks monoaminoxidase A and NMDA receptors, and seems to raise beta-endorphin/beta-lipotropin levels. However, it is still uncertain which of these actions are relevant in therapeutic doses. One new aspect is the antiviral effect of amantadine on Borna disease virus, which it is suspected may possibly play a role in affective disorders. All of these actions could constitute an antidepressant property, and it is suggested that amantadine might work as an antidepressant not through one, but through several mechanisms thought to be related to antidepressant activity. Effects of amantadine on symptoms of affective disorders have been demonstrated in several trials administering it for varying purposes. Additionally, animal studies as well as clinical trials in humans have hinted at an antidepressant activity of amantadine. We present here an overview of the current data. However, only a limited body of evidence is available, and further studies are needed to investigate the efficacy of amantadine as well as its modes of action in depression.