Was the blind compromised?
When discussing the limitations of their study of maintenance treatment with quetiapine, Chen et al mention that the effects of patients' and clinicians' expectancies cannot be assessed without double blind control. However, they do not report any possible compromises in blinding, as advocated by the CONSORT statement. Even though they have not reported this, it does not mean that it has not happened, as unblinding is common.
Unblinding seems likely in view of the differences in side effects, particularly sedation, and adverse effects that they report. Their liberal definition of relapse is also likely to have made it more subjective, increasing the potential for any bias introduced through unblinding.
If there has been unblinding, its impact on their results is of course unclear. However, doctors generally underestimate the effect of discontinuation problems, as is now accepted for antidepressants. Relapse rate after discontinuation of antipsychotics is high, but this may be more to do with what the antipsychotic medication has come to mean to people than any prophylactic effect of the drug.
 Chen EYN, Hui CLM, Lamm MML et al. Maintencance treatment with quetiapine versus discontinuation after one year of treatment in patients with remitted first episode psychosis: Randomised controlled trial. BMJ 2010; 341:c4024 [Full text]
 Schultz KF, Altman DG, Moher D. CONSORT 2010 Statement: updated guidelines for reporting parallel group randomised trials. BMJ 2010; 340:c332 [Full text]
 Fergusson D, Glass KC, Waring D, Shapiro S. Turning a blind eye: the success of blinding reported in a random sample of randomised, placebo controlled trials. BMJ, doi:10.1136/bmj.37952.631667.EE? [Full text]
 National Institute for Clinical Excellence Management of depression in primary and secondary care. NICE: London, 2004
Competing interests: No competing interests