Schizophrenia and the Metabolic Syndrome



It has been well known for at least 2 decades that schizophrenia is associated with excess mortality, premature death, and increased standard mortality from both natural and unnatural causes (Allebeck 1989). Patients with schizophrenia are at high risk of death from unnatural causes such as suicides and accidents; however, unnatural causes do not account for even half of the excess mortality. It is increasingly recognized that patients with schizophrenia are at increased risk for natural causes of death, primarily life-shortening illnesses (Marder et al. 2004). Epidemiological data have for decades evinced that natural causes afflict patients with schizophrenia much earlier than they do people in the general population. In fact, one meta-analysis concluded that at least 60% of the excess mortality in patients with schizophrenia is attributable to physical illness (Brown 1997). This well-received study also found that only 28% of the excess mortality is attributable to suicide and only 12% to accidents, leaving even more room than initially expected for the contribution of illness.

Individuals with schizophrenia have been shown to die younger from a variety of cardiovascular, infectious, gastrointestinal, respiratory, urogenital, and metabolic conditions. It is not clear if there is a common contributing pathological factor that underlies these epidemiological correlations. Probably the best candidate for such a unifying factor is the metabolic syndrome, a cluster of commonly comorbid metabolic derangements that tend to exacerbate one another and tend to afflict individuals with schizophrenia. It is not clear why the metabolic syndrome is relatively prevalent in populations with schizophrenia, but taken together, various points of evidence regarding this association are beginning to elucidate how the two are related and what can be done in regard to prevention.