Lithium addition in treatment-resistant depression.

The addition of lithium to antidepressants as a strategy for the management of depressed patients not responding to a tricyclic antidepressant was derived from the observation in animals that long-term administration of tricyclic antidepressant drugs enhances the sensitivity of postsynaptic neurones. Lithium administration increases the function of 5-HT neurones and thus might lead to amelioration of the non-responding depression. There have now been a substantial number of studies of lithium augmentation in non-responding depressed patients and a positive effect is consistently reported. The combination of lithium with a variety of antidepressants has not been associated with excessive reports of serious adverse events and therefore appears to be a useful approach to patients with a poor response to antidepressants.