Page 19 - JCBP-1-1

Journal of Clinical and
Basic Psychosomatics Smoking and schizophrenia symptoms

In addition to changes in positive and negative 3.1.1. Comparison of cognitive symptoms
symptoms, patients with SCZ may experience cognitive Numerous studies have investigated the correlation
improvement from nicotine . The literature on the between smoking and cognitive symptoms. One study
[15]
relationship between smoking and cognitive symptoms revealed that nicotine consumption may enhance cognition
is inconclusive [17,19] . Alterations in white matter structure in patients with SCZ [3,23] . Conversely, some authors have
have been linked to nicotine use and SCZ [20,21] , indicating identified smoking as a detrimental factor for cognition.
a potential pathway from nicotine, brain, and symptoms. For instance, nicotine has been shown to negatively affect
Correspondingly, cognitive deficits may rise after nicotine cognitive processes, such as spatial working memory .
[3]
withdrawal . Furthermore, individuals who smoke have been found
[22]
Many studies investigate the potential positive to have lower IQ scores compared to non-smokers .
[20]
and negative effects of smoking in many healthy and On the other hand, smoking has not been associated
psychiatric samples. However, it is crucial to demonstrate with improved cognitive performance in patients with
[17]
the relationship between smoking status and SCZ-related treatment-resistant SCZ .
risk factors and symptom severity in SCZ patients. The According to a few studies, some biological differences
objective of our investigation is to explore the association related to smoking have been identified in animal
between smoking status and symptoms of SCZ. Through models. For instance, nicotine has been shown to reverse
our study, we aim to gain a better understanding of how hypofrontality in mice models . Other studies have
[24]
smoking impacts SCZ symptoms and to identify potential reported potential improvements in attention and working
factors that may contribute to this relationship. memory due to smoking , as well as a positive effect on
[25]
divided attention .
[23]
2. Methods
In addition, research supports the presence of a sensory
PubMed was used to search articles in the literature. gating deficit in first-episode SCZ patients, which was less
Overall, 191 of the studies were found. Among them, 46 pronounced in those who currently smoke . The self-
[26]
were related to smoking and various SCZ symptoms (e.g., medication hypothesis proposes that smoking may alleviate
positive, negative, and cognitive). The keyword “smoking gating deficits in SCZ, and it suggests that treatments
self-treatment and SCZ” was used. Animal studies targeting genetic dysfunctions in nicotinic-glutamatergic
were included in the study. Articles related to cannabis interactions could improve cognitive deficits .
[27]
smoking, drug use, and smoking cessation were excluded
from the study. Studies consisting of commentary, review, 3.1.2. Comparison of positive symptoms
editorial, and meta-analysis were also excluded from the The existing literature on positive symptoms of SCZ presents
study. conflicting findings regarding the associations between
Most of the subjects were diagnosed according to the smoking status and the severity of SCZ symptoms. Some
Diagnostic and Statistical Manual of Mental Disorders, studies have reported a positive association, with smokers
Fourth edition criteria of SCZ. In addition, animal studies scoring higher on the positive subscale scores compared
[28]
using rats and mice as subjects were included in the study. to non-smokers . In addition, another study found that
[29]
smoker patients had more severe positive symptoms .
3. Results Conversely, a different study demonstrated that the
smokers had lower positive subscale scores compared to
3.1. Studies comparing smoking and non-smoking [16]
patients non-smokers . Moreover, there is an evidence suggesting
that tobacco smoking may have an impact on the
The main results of the study, comparing smoking development of psychosis . Similarly, a study reported
[30]
status, are presented in Table 1. Among the 46 studies a correlation between smoking and positive symptoms in
reviewed, the majority focused on the association between psychiatric patients . However, other studies have failed
[31]
smoking status and cognitive symptoms. However, to confirm this association, as SCZ patients often smoke
due to inadequate reporting in some studies, including for reasons unrelated to alleviating psychotic symptoms .
[32]
information on the AP type, dose, and other related
confounding factors, we were unable to incorporate these 3.1.3. Comparison of negative symptoms
parameters in our review. To address the self-treatment There is a paucity of literature on the relationship between
hypothesis of smoking, which is challenging to investigate smoking status and depressive symptoms. A recent study
in human studies due to ethical regulations, we included found no significant difference in depressive symptoms
animal studies in our analysis. based on smoking status . Moreover, DMXB-A, a
[29]

Volume 1 Issue 1 (2023) 2 https://doi.org/10.36922/jcbp.1014