A prospective naturalistic study of 326 panic-agoraphobic patients treated with antidepressants

How far the results of randomized controlled studies apply to everyday care cannot be judged without regular measurements of outcomes in daily practice. We report on systematic data from a 3-year naturalistic prospective study on panic disorder-agoraphobic (PDA) patients treated with antidepressants in a setting of routine clinical practice. Our aim is to describe the evolution of PDA in relation to the treatments employed, and to explore demographic and clinical characteristics that might be predictive of outcome.

326 DSM-III-R PDA patients treated with antidepressants in a setting of routine clinical practice were included in a 3-year naturalistic prospective study. We utilized structured and semi-structures instruments, including the Structured Clinical Interview for Diagnosis and the Longitudinal Interview Follow-up Examination. The main antidepressants used were imipramine (39%), clomipramine (28.5%) and paroxetine (23.3%); only 9% of patients received other antidepressants.

147 patients (45.1%) stayed on medication throughout the entire period of the follow-up. Of those who interrupted the treatment, 38% stayed in remission. The probability of achieving at least one remission during the 3-year follow-up period was 96.5% for PD and 95.9% for Agoraphobia. Relapses after a period of at least 2 months of complete remission were also common, and the probability of presenting at least one relapse during the 3-years follow-up period was 67.1% for PD and 39% for Agoraphobia. The longest period of remission of PD is associated with low severity, medium-lasting course in patients with an onset of the illness in young adulthood. Less severe agoraphobia associated with moderately severe panic attacks appears to confer a better control of phobic behavior. All three major drugs were reasonably well tolerated (only 9% dropped out because of side effects), with sexual dysfunction and increased appetite being the most common side effects at the last evaluation; in the first phase of the treatment anticholinergic effects and jitteriness were more common with TCAs.

Both classical antidepressants and paroxetine emerge as a useful treatment in the long-term management of PDA; paroxetine appears particularly useful in PDA patients because it was significantly less likely to induce jitteriness, thereby reducing barriers to compliance.