Brain Reward System May Underlie Tobacco Cravings in Schizophrenia

MedicalResearch.com Interview with:
Stéphane Potvin, PhD
Associate professor, Department of Psychiatry
Eli Lilly Chair in Schizophrenia Research
University of Montreal

MedicalResearch.com: What is the background for this study? What are the main findings?

Dr. Potvin:  Life expectancy is substantially reduced in schizophrenia, and one of the main factors contributing to this is the high prevalence of cigarette smoking in these patients. The leading hypothesis for cigarette smoking in schizophrenia is the self-medication hypothesis. Although some empirical results show that nicotine improves cognitive performance in schizophrenia, some authors have criticized the self-medication hypothesis for its implied (and unintented) justification of cigarette smoking in schizophrenia. About a decade ago, it has been hypothesized that cigarette smoking may be more reinforcing in schizophrenia patients, due to biological dysfunctions common to schizophrenia and tobacco use disorder. However, that model had not been formally tested.

Based on recent findings showing that cigarette cravings are increased in schizophrenia smokers, compared to smokers with no comorbid psychiatric disorder, we performed a neuroimaging study on cigarette cravings in schizophrenia. Unless we are wrong, this was most probably the first study to do so. We found that relative to control smokers, smokers with schizophrenia had increased activations of the ventro-medial prefrontal cortex in response to pleasant images of cigarette. What is is interesting is that the ventro-medial prefrontal cortex is one of the core regions of the brain reward system, which mediated the reinforcing effects of several psycho-active substances, including tobacco. As such, our results tend to confirm the assumption that cigarette might be more reinforcing in schizophrenia smokers.

MedicalResearch.com: What should clinicians and patients take away from your report?

Dr. Potvin: Self-medication is not the sole explanation for the increased prevalence of cigarette smoking in schizophrenia. Of course, our results do not suggest either that the reasons for the increased prevalence of cigarette smoking in schizophrenia are purely biological. Multiple and complex factors are likely to be involved.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Dr. Potvin: First of all, let’s be prudent. These results need to be replicated.

MedicalResearch.com: Is there anything else you would like to add?

Dr. Potvin: Psychiatric patients, including patients with schizophrenia, have been typically excluded from neuroimaging studies on cigarette cravings. We hope that our results will encourage a shift in the literature.

Many thanks for having the opportunity to discuss our results. Schizophrenia is one of the top 10 causes of disability in developed countries.

Citation:

Stéphane Potvin, Ovidiu Lungu, Olivier Lipp, Pierre Lalonde, Vessela Zaharieva, Emmanuel Stip, Jean-Pierre Melun, Adrianna Mendrek. Increased ventro-medial prefrontal activations in schizophrenia smokers during cigarette cravings. Schizophrenia Research, 2016; 173 (1-2): 30 DOI: 10.1016/j.schres.2016.03.011

 

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