Next-step strategies for panic disorder refractory to initial pharmacotherapy: a 3-phase randomized clinical trial.
BACKGROUND
More data are needed to guide next-step interventions for panic disorder refractory to initial intervention.


METHODS
This 24-week randomized clinical trial (RCT) enrolled 46 patients with DSM-IV-defined panic disorder from November 2000 to April 2005 and consisted of 3 phases. Patients who failed to meet remission criteria were eligible for randomization in the next treatment phase. Phase 1 was a 6-week lead-in with open-label sertraline flexibly dosed to 100 mg (or escitalopram equivalent) to prospectively define treatment refractoriness (lack of remission). Phase 2 was a 6-week double-blind RCT of (1) increased-dose selective serotonin reuptake inhibitor (SSRI) versus (2) continued SSRI plus placebo. Phase 3 was a 12-week RCT of added cognitive-behavioral therapy (CBT) compared to "medication optimization" with SSRI plus clonazepam. Primary endpoints were remission and change in Panic Disorder Severity Scale (PDSS) score in the intent-to-treat sample in each phase.


RESULTS
In phase 1, 20.5% (8/39) of the patients achieved remission, and only baseline severity predicted endpoint PDSS score (beta [SE] = 1.04 [0.15], t = 6.76, P < .001). In phase 2, increasing the SSRI dose did not result in greater improvement or remission rates (placebo 15% [n = 2] vs increased dose 9% [n = 1]: Fisher exact test P = NS). In phase 3, remission was minimal (medication optimization = 11% [n = 1]; CBT = 10% [n = 1]), with a lack of group difference in PDSS score reduction (t(17) = 0.51, P > .60) consistent with a small effect size (d = 0.24).


CONCLUSIONS
Although power was limited and larger studies are needed, we failed to find evidence for greater benefit of increased SSRI dose versus continuation of current dose for panic disorder symptomatic after 6 weeks at moderate dose. Further, augmentation with CBT or medication optimization with clonazepam augmentation in nonremitted panic after 12 weeks of an SSRI did not differ, suggesting that both are reasonable next-step options. However, low overall remission rates in this comorbid refractory population suggest that better predictors of response to specific treatments over time and additional interventions are needed.


BACKGROUND
clinicaltrials.gov Identifier: NCT00118417.
Simon
Naomi M
NM
Center for Anxiety and Traumatic Stress Disorders, Massachusetts General Hospital, Simches Research Building, 2nd Floor, 185 Cambridge St, Boston, MA 02114, USA. nsimon@partners.org.
Otto
Michael W
MW
Worthington
John J
JJ
Hoge
Elizabeth A
EA
Thompson
Elizabeth H
EH
Lebeau
Richard T
RT
Moshier
Samantha J
SJ
Zalta
Alyson K
AK
Pollack
Mark H
MH
D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use*; D015283:Citalopram / Q000627:therapeutic use; D002998:Clonazepam / Q000627:therapeutic use*; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D003131:Combined Modality Therapy; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004311:Double-Blind Method; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016584:Panic Disorder / Q000188:drug therapy* / Q000628:therapy*; D010919:Placebos; D011569:Psychiatric Status Rating Scales; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D020280:Sertraline / Q000627:therapeutic use; D012720:Severity of Illness Index; D013313:Stress Disorders, Post-Traumatic / Q000188:drug therapy; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D000927:Anticonvulsants; D015283:Citalopram; D002998:Clonazepam; D010919:Placebos; D017367:Selective Serotonin Reuptake Inhibitors; D020280:Sertraline