Researchers from University Medical Center in Groningen, The Netherlands, examined the longterm effectiveness of three treatments for panic disorder, with or without agoraphobia: cognitive-behavioral therapy (CBT), pharmacotherapy using a selective serotonin reuptake inhibitor (SSRI), or the combination of both (CBT + SSRI). As a secondary objective, the relationship between treatment outcome and 7 predictor variables was investigated.
One hundred fifty patients were assigned to a treatment arm lasting one year. Pharmacotherapists were free to choose between 5 SSRIs currently marketed in The Netherlands. Outcome was assessed after 9 months of treatment (posttest 1), after discontinuation of treatment (posttest 2), and at 6 and 12 months after treatment discontinuation (follow-up 1 and follow-up 2).

In the sample population, 48% did not suffer from agoraphobia or suffered from only mild agoraphobia, while 52% suffered from moderate or severe agoraphobia. Patients in each treatment group improved significantly from pretest to posttest 1 on the primary outcome measures of level of anxiety (P < .001), degree of coping (P < .001), and remitter status (P < .001), as well as on the secondary outcome measures of depressive symptomatology (P < .001), and from pretest to posttest 2 for health-related quality of life (P < .001). Gains were preserved from posttest 2 throughout the follow-up period.
The study found some superiority of CBT + SSRI and SSRI over CBT alone, as observed at posttest 1.  However, at both follow-ups, differences between treatment modalities became nonsignificant.  Client satisfaction appeared to be high at the endpoint of treatment, with patients receiving CBT + SSRI appearing slightly (P < .05) more satisfied than those receiving CBT only.
No fall-off in gains was observed for either treatment modality after treatment discontinuation. SSRIs were associated with adverse events.  Gains produced by CBT were slower to emerge than those produced by CBT + SSRI and SSRI, but CBT ended sooner.
Citation;  van Apeldoorn FJ, Timmerman ME, Mersch PP, van Hout WJ, Visser S, van Dyck R, den Boer JA. A randomized trial of cognitive-behavioral therapy or selective serotonin reuptake inhibitor or both combined for panic disorder with or without agoraphobia: treatment results through 1-year follow-up. Journal of Clinical Psychiatry. 2010 May;71 (5): pages 574-86. [email protected]