There is uncertainty whether some antipsychotics are better at preventing relapses in schizophrenia than others, which is in part because of nonrepresentative patient populations in randomised trials and the possibility of selection bias in observational studies.
In a study of 29,823 patients aged 16 to 64 years, researchers used national data from Sweden to compare antipsychotic efficacy, applying a method whereby each subject acts as their own control to eliminate the risk of selection bias.
Over a median follow-up of 6.9 years, monotherapy with long-term injectable antipsychotics, such as paliperidone (hazard ratio [HR] 0.51, 95% confidence interval [CI], 0.41–0.64),) and zuclopenthixol (HR 0.53, 95% CI, 0.48–0.57), as well as clozapine (HR 0.53, 95% CI, 0.48–0.58), were associated with the lowest risk of rehospitalisation. Long-acting injectable antipsychotics were also significantly more effective than their oral equivalents.
Reporting in JAMA Psychiatry
(online, 7 June 2017), the researchers say the results show that there are substantial differences in the risk of rehospitalisation between treatments for schizophrenia.
 Tiihonen J, Mittendorfer-Rutz E, Majak M et al. Real-world effectiveness of antipsychotic treatments in a nationwide cohort of 29,823 patients with schizophrenia. JAMA Psychiatry 2017. doi:10.1001/jamapsychiatry.2017.1322