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Placebo effects in adult and adolescent patients with schizophrenia: combined analysis of nine RCT s
Author(s) -
Kubo K.,
Fleischhacker W. W.,
Suzuki T.,
YasuiFurukori N.,
Mimura M.,
Uchida H.
Publication year - 2019
Publication title -
acta psychiatrica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.849
H-Index - 146
eISSN - 1600-0447
pISSN - 0001-690X
DOI - 10.1111/acps.12960
Subject(s) - placebo , positive and negative syndrome scale , schizophrenia (object oriented programming) , medicine , randomized controlled trial , logistic regression , antipsychotic , psychology , randomization , psychiatry , psychosis , alternative medicine , pathology
Objective To examine characteristics of placebo responders and seek optimal criteria of early improvement with placebo for predicting subsequent placebo response in patients with schizophrenia. Method Data of 672 patients with schizophrenia randomized to placebo in nine double‐blind antipsychotic trials were analyzed. Multiple logistic regression analyses were conducted to examine associations between placebo response at week 6 (i.e., a ≥ 25% reduction in the Positive and Negative Syndrome Scale [ PANSS ] score) and gender, age, study locations, baseline PANSS total or Marder 5‐Factor scores, and per cent PANSS score reduction at week 1. Predictive power of improvement at week 1 for subsequent response was investigated; sensitivity and specificity of incremental 5% cutoff points between 5% and 25% reduction in the PANSS total score at week 1 were calculated. Results Per cent PANSS total score reduction at week 1 and lower PANSS Marder disorganized thought scores at baseline were significantly associated with subsequent placebo response. A 10% reduction in a per‐protocol analysis or a 15% reduction in last‐observation‐carried‐forward analysis in the PANSS total score at week 1 showed the highest predictive power. Conclusion These findings are informative to identify potential placebo responders at the earliest opportunity for optimal trial design for schizophrenia.