Some patients being treated for recurrent major depression experience a return of depressive symptoms despite a constant maintenance dose of an antidepressant, a phenomenon known as breakthrough depression. A total of 145 psychiatrists who were members of the Massachusetts Psychiatric Society responded to a survey about intervention in hypothetical cases of breakthrough depression if the patient was taking either 20 mg of fluoxetine, 100 mg of sertraline, 100 mg of nortriptyline, or 40 mg of fluoxetine. For all drugs and dosages, the most popular choice was increasing the dosage, followed by augmenting with lithium or another antidepressant or changing to a different drug.