Schizophrenia and tobacco smoking comorbidity: nAChR agonists in the treatment of schizophrenia-associated cognitive deficits
Tobacco smoking is a preventable cause of morbidity and mortality throughout the world. Very high rates of tobacco smoking are seen in patients with schizophrenia. Importantly, smokers with schizophrenia generally have higher nicotine dependence scores, experience more severe withdrawal symptoms upon smoking cessation, have lower cessation rates than healthy individuals, and suffer from significant smoking-related morbidity and premature mortality compared with the general population. Interestingly, significant disturbances in cholinergic function are reported in schizophrenia patients. The high smoking-schizophrenia comorbidity observed in schizophrenia patients may be an attempt to compensate for this cholinergic dysfunction. Cholinergic neurotransmission plays an important role in cognition and is hypothesized to play an important role in schizophrenia-associated cognitive deficits. In this review, preclinical evidence highlighting the beneficial effects of nicotine and subtype-selective nicotinic receptor agonists in schizophrenia-associated cognitive deficits, such as working memory and attention, is discussed. Furthermore, some of the challenges involved in the development of procognitive medications, particularly subtype-selective nicotinic receptor agonists, are also discussed. Amelioration of schizophrenia-associated cognitive deficits may help in the treatment of schizophrenia-smoking comorbidity by promoting smoking cessation and thus help in the better management of schizophrenia patients.