However, although the complementary findings of Bartoli et al. (1) are relevant, we believe they should still be interpreted with caution. Mitchell et al. (3) found disease stage and medication history to be influential, and these factors are not controlled for in these comparisons. Moreover, both Mitchell et al. (4) in schizophrenia patients and Vancampfort et al. (2) in bipolar patients found that age was also a significant moderating variable for the prevalence of metabolic syndrome in severely mentally ill patients. As in the general population, older age is associated with higher metabolic syndrome prevalence rates. However, in the majority (8/11) of the studies included in the Bartoli et al. analysis (1), patients with bipolar disorder and schizophrenia were not matched for age. Therefore, we suggest that more research with age-matched, medication-equivalent clinical populations that have similar durations of illness is needed before we can conclusively state that patients with bipolar disorder and schizophrenia have comparable risks for metabolic syndrome.