There is a robust association between positive symptoms of schizophrenia and smoking. This relationship extends to psychometric risk for schizophrenia (schizotypy). We sought to determine whether smoking in schizotypy is best understood in terms of self-medicating or risk-taking behaviour. The self-medication perspective holds that individuals with schizophrenia smoke to relieve stress. By smoking, cortisol levels increase, stimulating negative feedback circuits that reduce the hypothalamic-pituitary-adrenal (HPA) axis stress response. Increased HPA activation also stimulates dopamine release, promoting the expression of positive schizotypal experiences. In contrast, the risk-taking perspective holds that elevated dopamine promotes risk-taking behaviour, including substance misuse, by reducing reward sensitivity and increasing sensation-seeking.

Undergraduates (n = 230) reported current and past nicotine use and completed the Schizotypal Personality Questionnaire and a self-report measure of stress sensitivity.

Consistent with risk-taking, positive features of schizotypy predicted having ever smoked (OR = 1.02, P < 0.05) but did not distinguish current smoking from non-smoking (OR = 0.99). The self-medication hypothesis was examined in two ways. When smoking status was regressed onto positive schizotypy and stress, stress was found to predict current smoking (OR = 1.08, P < 0.05) but not having ever smoked (OR = 1.09). Secondly, stress and current smoking interacted to predict positive schizotypy (ß = 0.31, P < 0.05).

Risk-taking and self-medicating each contributed to the relation between smoking and schizotypy, but in different ways. Risk-taking seems to contribute to having ever smoked whereas current smoking seems to reflect self-medicating behaviour.

The authors have not supplied their declaration of competing interest.