Sixty patients with agoraphobia with panic attacks or panic disorder who completed a 4-month combined drug and behavioral group treatment program and were discharged on a regimen of alprazolam were interviewed 1.7 to 4 years (mean, 2.5 years) after discharge. At follow-up (FU), 18 (30%) of the patients had discontinued alprazolam treatment, 36 (60%) continued with a lower dose, 3 (5%) received the same dose, and 3 (5%) received an increased dose compared with discharge. A lower frequency of panic attacks at admission was associated with an increased ability to discontinue alprazolam treatment. There was little evidence of tolerance to the antipanic effects of alprazolam. Panic attack frequency dropped from a mean of 4.4 attacks per week at admission to 1.2 attacks per week at discharge and remained decreased at 1.6 attacks per week at FU. Treatment gains in the program were maintained or enhanced on 11 of 14 behavioral measures at FU and were similar in the groups that were receiving and not receiving alprazolam. Patients receiving nonpharmacologic therapy in the FU period tended to have greater symptom severity, possibly due to self-selection. A lifetime diagnosis of major depression at admission was associated with higher levels of depressive and anxiety symptoms and higher alprazolam doses at FU. Episodes of major depression were common in the FU period and did not appear to be prevented by initial alprazolam and behavioral therapy or by low-dose alprazolam maintenance.(ABSTRACT TRUNCATED AT 250 WORDS)