Circulatory neurosteroid levels in smoking and non-smoking chronic schizophrenia patients

IntroductionSchizophrenia patients display an extremely high rate of smoking. Neurosteroids appear to play a possible role in the pathophysiology and management of schizophrenia and have been proposed to be involved in the pathophysiology of nicotine addiction. Although many studies have evaluated blood levels of neurosteroids in schizophrenia patients, only a few studies have taken into consideration the effect of smoking on levels of neurosteroids in the illness.MethodsForty-five DSM-IV-TR chronic schizophrenia patients were sampled for plasma levels of three steroids: cortisol, dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulphate (DHEA-S). Patients were rated with the Positive and Negative Syndrome Scale (PANSS) and provided data on their smoking behavior.ResultsThe mean level of plasma cortisol in our sample (N = 45) was 197.9 nmol/L (S.D. = 81.5), and the levels of DHEA and DHEA-S were 23 nmol/L (S.D. = 5.5) and 4276.6 nmol/L (S.D. =2665.58), respectively. Despite a trend for lower levels of cortisol, DHEA and DHEA-S among the smokers, only DHEA, but not DHEA-S and cortisol, was significantly lower among the smokers (33% decrease, p = 0.012). Smoking predicted the positive and negative scores of the PANSS, whereas cortisol was correlated with the PANSS-negative subscale.ConclusionsSmoking in chronic schizophrenia patients appears to be associated with lower DHEA levels. The role of this decrease in the pathophysiology of nicotine addiction and schizophrenia merits further investigation.