A review of the effects of moderate alcohol intake on the treatment of anxiety and mood disorders.

Background: There is no published review to help the clinician clarify the potential role of moderate ethanol consumption in patients being treated for anxiety and mood disorders. Product labels and textbook chapters routinely warn the individual against the consumption of ethanol when using prescription psychotropic drugs. A general understanding is that the reason for this recommendation is the potential for adverse synergistic effects or sedation and decreased psychomotor performance. What is overlooked by this emphasis on safety is the effect of alcohol use both on the underlying psychiatric disorder being treated and on the effectiveness of drug therapy.

Method: We review the available literature on the interactions of ethanol with neurotransmitters and psychotropic medications and explore the clinical consequences of these interactions.

Results: Ethanol might affect anxiety and mood disorders by different mechanisms. Principal among these are the effects of ethanol on multiple neurotransmitter systems, which adapt in different ways to the acute and/or chronic presence of ethanol. Perturbations in the balance of CNS neurotransmitter systems may modify the acute clinical course of primary mood disorders and undermine the therapeutic response to psychotropic medications. Ethanol also modifies the clearance and disposition of psychotropic metabolites and interferes with their clinical effectiveness. Neurotransmitter responses may additionally be manifested clinically by rebound phenomena, akin to a subsyndromal withdrawal, which affect sleep and precipitate anxiety and mood symptoms. Recent alcohol use also may alter the subjective interpretation of the patient's "internal milieu," causing confusion and eliciting reactive psychopathology.

Conclusion: While much research remains to be done, there is abundant evidence that patients with mood and anxiety disorders should abstain from even moderate ethanol use, as this adversely affects their clinical course and response to treatment.