Abstract
Schizophrenic patients have higher smoking rates than the general population. Studies show that smoking may be a form of self-medication in an attempt to alleviate cognitive deficits in schizophrenic patients of European background. This study examined the relationships between smoking and cognitive deficits in Chinese schizophrenic patients, which have previously received little systemic study. We recruited 580 male chronic patients meeting DSM-IV criteria for schizophrenia and 175 male control subjects who were matched on age and education. The subjects completed a detailed cigarette smoking questionnaire, the Fagerstrom Test for Nicotine Dependence (FTND), and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Patients also were rated on the Positive and Negative Symptom Scale (PANSS), the Simpson and Angus Extrapyramidal Symptom Rating Scale (SAES), and the Abnormal Involuntary Movement Scale (AIMS). All five RBANS subscales except for the Visuospatial/Constructional index showed significantly lower cognitive performance for schizophrenics than normal controls. The schizophrenic smokers scored lower than the schizophrenic non-smokers on the RBANS total score and the Visuospatial/Constructional and Immediate Memory indices. Similarly, the control smokers scored lower than the control non-smokers on the RBANS total score and the Immediate Memory index . Also, the schizophrenic smokers consistently performed the poorest on the cognitive domains of the RBANS. Among the schizophrenic patients, smokers displayed significantly fewer negative symptoms than non-smokers. Using multivariate regression analysis the following variables were independently associated with the RBANS total score: years of education, PANSS negative symptom score, age at schizophrenia onset, and number of hospitalizations. Our results show that smoking is associated with significant cognitive impairment in both schizophrenic patients and normal controls, but the smokers with schizophrenia had a reduced level of negative symptoms, suggesting that the benefits of smoking for those with schizophrenia may be limited to certain aspects of a given clinical phenotype.
Highlights
Schizophrenia is a severe psychiatric disorder characterized by multi-faceted deficits in neurocognitive function, including learning, memory, attention, executive functioning and cognitive processing speed [1,2,3,4]
Some studies indicate that cigarette smoking or nicotine may ameliorate some of the cognitive deficits in schizophrenic patients [18,19,20,21,22,23] or may normalize deficits in auditory sensory gating in both schizophrenia and their first-degree relatives [24,25,26], suggesting that cigarette smoking or nicotine serves as a form of self-medication [27,28,29,30]
The schizophrenic patients had a higher prevalence of current smoking (x2 = 38.6, df = 1, p,0.0001), and lower frequency of smoking cessation (x2 = 13.1, df = 1, p,0.0001)
Summary
Schizophrenia is a severe psychiatric disorder characterized by multi-faceted deficits in neurocognitive function, including learning, memory, attention, executive functioning and cognitive processing speed [1,2,3,4]. Smokers with schizophrenia may have higher daily cigarette consumption, favor stronger cigarettes and extract more nicotine from their cigarettes [15,16] than normal smokers These observations remain true across cultures and countries and when controlling for possible confounds, such as marital and socio-economic status, alcohol use, antipsychotic use, or institutionalism [12,17]. Some studies indicate that cigarette smoking or nicotine may ameliorate some of the cognitive deficits in schizophrenic patients [18,19,20,21,22,23] or may normalize deficits in auditory sensory gating in both schizophrenia and their first-degree relatives [24,25,26], suggesting that cigarette smoking or nicotine serves as a form of self-medication [27,28,29,30]. This observation suggests that a dysfunction in nicotinic acetylcholine receptor signaling may be involved in the etiology of cognitive deficits in schizophrenia [31,32]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
