Is there a Relationship Between Caffeine Intake and Smoking and Positive and Negative Symptom Severity in Schizophrenia?

Background: It has been reported that caffeine intake and smoking are more frequent in patients with schizophrenia than the general population. However, the cause of high caffeine and smoking and its correlation with positive and negative symptoms is unclear. Therefore, the aim of the present study is to evaluate the correlation between daily caffeine intake and smoking and the severity of positive and negative symptoms in patients with schizophrenia.

Subjects And Methods: This study included 177 participants, 89 of whom were healthy controls and 88 patients with schizophrenia. Scale for the Assessment of Positive Symptoms (SAPS) and Scale for the Assessment of Negative Symptoms (SANS) scales were applied to the patients with schizophrenia to measure the severity of positive and negative symptoms of the disease.

Results: The amounts of caffeine and tobacco consumption were significantly higher in the patients group than healthy controls (p=0.001 and p<0.001, respectively). There was no significant correlations between daily caffeine consumption and SAPS or SANS scores in patients with schizophrenia. There was a significant positive relationship between SAPS-delusions score and tobacco consumption.

Conclusions: Our study is the first study in the literature that examines the relationship between caffeine and cigarette intake and SANS and SAPS scales in patients with schizophrenia. Although caffeine intake is higher in patients with schizophrenia than healthy controls, this study is valuable as it shows that it is not associated with symptom severity. In addition, although it is known that smoking is high in patients with schizophrenia, this study showed a positive relationship between SAPS-delusion scores and tobacco consumption.