Patients with bipolar disorder may experience "mood switching" (mood conversion) if they are treated with an antidepressant. The occurrence of mood switching while receiving an antidepressant may be the first indication that the patient has bipolar disorder.


Mood switching refers to emergence of a mania or hypo-mania state related to the drug therapy. There should be no normothymic period between the depressive and manic/hypomanic states (Henry and Demotes-Mainard).


Features of anti-depressant mood switching:

(1) The risk appears greatest with tricyclic antidepressants. The risk is less with buproprion or a serotonin reuptake inhibitor (SSRI).

(2) The risk of switching is reduced if the patient is receiving a mood stabilizer such as lithium. A patient with mild depression can sometimes be managed with lithium alone.

(3) For psychotic depression a neuroleptic drug is added.

(4) The antidepressant may be discontinued during the maintenance phase if rapid cycling is a problem.

(5) The diagnosis of drug-induced mood switching is supported if the switching did not occur prior to initiation of therapy with the drug, emerges with drug therapy, and stops after the drug is discontinued.



• Koszewska and Rybakowski hypothesized that mood conversion with tricyclic antidepressants may be related to anticholinergic activity.


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