Does smoking affect the prevalence of caffeine use in schizophrenia?

INTRODUCTION: Caffeine acts as a competing antagonist of adenosine receptors, increasing the release of norepinephrine and the activation of noradrenergic neurons. Long-standing schizophrenia patients frequently develop a comorbidly high daily caffeine intake. This could be explained by its relationship with smoking [1,2]. OBJECTIVES: To determine caffeine consumption in schizophrenia and predisposing factors. METHODS: Cross-sectional study designed on a sample of 68 outpatients with a follow-up of at least 5 years at the Mental Health Unit, aged between 18 and 65 years, diagnosed with schizophrenia (ICD-10). Average daily caffeine intake was quantified by reference values for each beverage: coffee (66.7mg/100ml), tea (30mg/100ml), soft or energy drinks (11.5mg/100ml). High intake was defined as a consumption of ≥200mg of caffeine per day. Retrospective review of medical records revealed tobacco use and negative symptoms observed on the PANSS scale. Statistical analysis were performed using SPSS v21.0 (significance p<0.05). RESULTS: 88.2% of the subjects were daily caffeine consumers with a mean intake of 146.7mg/day (SD=5.8), and a mean consumption time of 6.2 years. Coffee was the predominant beverage in 66.7% of the cases, followed by soft or energy drinks (25%) and tea (0.1%). 45% of participants also had a high caffeine intake of ≥200 mg/day. Comorbid smoking was found in 93% of these patients. Negative symptomatology prevailed among caffeine consumers (PANSS-N= 41.3). CONCLUSIONS: Xanthine abuse seems to be highly prevalent in people with schizophrenia, and there may be a relationship with smoking and negative psychotic symptoms. DISCLOSURE: No significant relationships.