Tobacco Use Decreases Visual Sensitivity in Schizophrenia

Abstract

Smoking prevalence in patients who are diagnosed with schizophrenia (SCZ) is higher than in the general population. Chronic tobacco use in SCZ patients may reduce the side effects of antipsychotic drugs, thus serving as a self-medication for such side effects. Understanding the ways in which chronic tobacco use influences visual sensitivity has clinical implications, which may serve as a tool for non-invasively diagnosing early-stage visual processing deficits. The present study evaluated the effects of chronic tobacco use on visual sensitivity in SCZ patients. Our purpose was to provide new directions for future research, mainly psychophysical and electrophysiological studies. In the present study, 40 smoker controls (SC), 20 SCZ tobacco users, and 20 SCZ tobacco nonusers were recruited from the Psychosocial Care Center. Visual sensitivity was compared between both SCZ groups and the SC group. Patients with SCZ who were chronic tobacco users presented lower visual sensitivity for chromatic (p < 0.001) and achromatic (p < 0.001) stimuli compared with the other groups. Our findings highlight the need to evaluate possible addictive behavior in patients with SCZ, which may contribute to public policies that seek to improve the quality of life of SCZ patients and their families.

Impairments of facial detection in tobacco use disorder: baseline data and impact of smoking duration

“…Also, it helps to understand why some populations have high rates of tobacco consumption. 39 In summary, the ability to detect, recognize, and process faces constitutes one of the key neurocognitive bases for many social-order phenomena, e.g., social attribution. 40 Our findings propose, without establishing causal relationships, that substantial enough impairments are observed in the facial discrimination ability of subjects with TUD to warrant further research.…”

Combined influence of illness duration and medication type on visual sensitivity in schizophrenia

“…For example, the use of different medications has been a confounding factor in several previous studies. 4,20,21 The exact mechanism of the medications' Visual impairment in schizophrenia adverse effects and its relationship with illness duration are not fully understood. As mentioned above, some studies on this issue have used different methods and paradigms but have yielded similar results.…”

“…12 The session ended after 12 contrast reversals occurred. Higher contrast sensitivity values indicated that the participant had higher sensitivity (for procedural details, see Fernandes et al 1,4,11,13 ).…”

“…3 The exclusion criteria for SCZ patients were: a) antipsychotic polypharmacy; b) comorbidities; c) neurological disorders, such as intellectual disability; d) discontinuation of medication at any time; and e) tobacco use disorder. 4 See below for additional exclusion criteria for all subjects. Further details about medication can be found in the precursor study.…”

“…The contrast sensitivity function was measured for spatial frequencies ranging from 0.2 to 20 cpd using linear sine-wave gratings. The stimuli and apparatus have been described elsewhere (for details, see Fernandes et al 1,4,11 ).…”