Increased caffeine and nicotine consumption in community-dwelling patients with schizophrenia

It is known that people with schizophrenia make poor dietary choices and smoke at alarmingly high rates. There is also anecdotal evidence that they may ingest large amounts of caffeine. However, while smoking habits in this population have been examined, no recent study has quantified caffeine consumption taking into account various dietary caffeine sources unrelated to coffee including convenience foods such as candy bars, chocolate or soft drinks, and compared results to US population data.

We employed 24-h diet recalls to assess dietary habits in a sample of outpatients suffering from schizophrenia or schizoaffective disorder. Caloric intake and caffeine consumption were quantified and the relationship to various sociodemographic variables including body mass index (BMI) and dietary quality was examined.

146 patients were recruited. Mean BMI in the sample was 32.7+/-7.9. Patients ingested 3,057+/-1,132 cal on average. Patients smoked at higher rates (59.6% vs. 23.4%, p< or =0.001), higher numbers of cigarettes/day (24+/-14.4 vs. 13.5+/-11.3, t=8.549, p<0.001) and ingested more caffeine (471.6+/-584.6 mg vs. 254.2+/-384.9 mg, t=6.664, p<0.001) than US population comparisons. Caffeine consumption was correlated to the number of cigarettes smoked daily (r=0.299, p< or =0.001), but not to BMI (r=0.134, p=0.107) or dietary parameters such as caloric intake (r=0.105, p=0.207).

Community-dwelling schizophrenia patients consume significantly more caffeine and nicotine than US population comparisons. Clinicians should be aware that while a significant proportion of patients are overweight and have poor dietary quality - which merits lifestyle counseling on its own - there is a lack of correlation between those factors and smoking and caffeine intake. Thus, lifestyle modification counseling in all patients should address smoking and caffeine intake concurrently.