The role of XXXX expectancy in placebo and nocebo effects in antidepressant trials.

@entity1 @entity308 @entity204 @entity905
OBJECTIVE: To determine whether @entity1 expectancy plays a role in observed placebo and nocebo effects in 2 clinical trials. METHOD: Data were reanalyzed from 2 @entity905 -discontinuation studies conducted from March 1990 to September 1992 and from May 1997 to December 2002. The 673 outpatients included were aged 18-65 years with DSM-III-R @entity308 ( @entity308 ), responded to 12-week duration open treatment, and were randomized to continued @entity905 or placebo for an additional year. @entity1 in 1 of the included studies received a fixed dose of @entity905 20 mg daily, while the second study utilized flexible @entity905 doses up to 60 mg daily. Mixed @entity204 whether the possible randomization to placebo at 12 weeks resulted in significant @entity308 worsening across treatments. Correlations were computed between early symptom change (weeks 1-3 of open treatment) and postrandomization symptom change (weeks 13-16 following randomization). RESULTS: @entity1 continuing to receive @entity905 and those switched to placebo had significantly higher mean @entity308 ( @entity308 ) scores immediately postrandomization compared to the final weeks of open treatment (P < .001 for both @entity905 - and placebo-treated @entity1 ). In both studies, early @entity308 change was significantly correlated with postrandomization @entity308 change for @entity1 receiving @entity905 (r = -0.46, P < .001) as well as placebo (r = -0.48, P < .001). CONCLUSIONS: The possibility of receiving placebo following 12 weeks of open @entity905 was associated with significant symptom worsening in 2 large @entity905 discontinuation studies. Worsening @entity308 scores following randomization were significantly associated with the degree of improvement @entity1 experienced during weeks 1-3 of open treatment. These results suggest that treatment changes influence @entity1 ' expectations of improvement, which, in turn, affect their @entity308 symptoms.
