Not All Masks Are Created Equal: Masking Success in Clinical Trials of Children and Adolescents

摘要

The current study assessed the success of masking omega-3 (Omega 3) and psychotherapy in clinical trials of youth with depression or bipolar spectrum disorder. Participants were youth ages 7-14 with DSM-IV-TR diagnosed depressive (n = 72) or bipolar spectrum (n = 23) disorders. Inclusion diagnoses were depressive disorder, cyclothymic disorder, or bipolar disorder not otherwise specified. Exclusion diagnoses included bipolar I or II disorder, chronic medical condition or autism. Youth participated in 2 x 2 randomized controlled trials, in which they received Omega 3 or placebo (PBO) and psychoeducational psychotherapy (PEP) or active monitoring (AM). Participants and study staff (including independent interviewers) were masked to Omega 3/PBO allocation. Besides the masked independent interviewers, one co-principal investigator (Co-PI) was fully masked to both conditions and completed all consensus conference ratings postrandomization. At the endpoint assessment or last completed interview, interviewers and the masked Co-PI guessed whether each child was assigned to Omega 3 or PBO and to PEP or AM. Masking failure was calculated using the degree of correct guesses above chance level using binomial tests across all participants for Omega 3 versus PBO and PEP versus AM. For all guessers, Omega 3 allocation was guessed correctly approximately half the time (50%-52.5%). Rates of correct guessing were higher for PEP, but only the interviewer guesses were correct significantly more often (58.5%-68.7%) than chance. Reporting of masking success should be an essential element of RCTs. Psychotherapy is generally more difficult to mask, but with attentive masking procedures reasonable masking can be achieved.