Phenelzine treatment of selective mutism in four prepubertal children.

Four children, ages 5 1/2 to 7 years, diagnosed with selective mutism and successfully treated with phenelzine are presented. All four children were anxious and extremely shy and had family histories of anxiety and shyness. The first three children were treated with phenelzine prior to reports that fluoxetine was helpful in some cases. The fourth child was treated initially with fluoxetine and had shown only minimal improvement after 10 months of doses up to 16 mg daily. Phenelzine doses ranged from 30 to 60 mg/day and treatment, including medication taper, lasted from 24 to 60 weeks. The phenelzine was generally well-tolerated and weight gain was the most common side effect. No hypertensive reactions or serotonin syndromes occurred. There was no recurrence of mutism after medication discontinuation. The authors conclude that phenelzine can be an effective treatment for selective mutism, but because of the possibility of serious food and drug interactions and the necessary dietary restrictions, it should be reserved for cases that do not respond to behavior therapy and fluoxetine or other specific serotonin reuptake inhibitors.