Research view
Title: | The association of circadian typology with cognition and smoking status: a cross-sectional Egyptian study |
Author: | Nevin F.W. Zaki and Mohamed A. El-Hadidy |
Abstract: |
Introduction
Circadian rhythmic expression differs among individuals. These differences are often
labeled as morningness–eveningness or chronotype. Three main phenotypic variants
of human chronotype exist: morning type, neither type, and evening type. Nicotine is a
psychoactive stimulant that is abundantly present in cigarettes. Few data are available
about the possible associations between the stimulant effect of nicotine and the phase
shift of circadian rhythm and chronotype of individuals abusing nicotine (smokers).
Different brain pathways explain the associations between chronotypes and various
addictive behaviors, although the impact of nicotine on cognition remains unclear.
This study is based on the hypothesis that circadian typology is a risk factor for
smoking and for higher levels of nicotine consumption, dependence, and associated
cognitive changes in smokers.
Aim
This study aimed to estimate the possible associations between circadian typology
and smoking. Measures quantifying nicotine dependence and smoking status were
applied to the recruited sample. In addition, cognitive assessment of the sample was
carried out.
Participants and methods
A representative sample of smokers (total N= 100) of both sexes were randomly
selected. All patients had been smoking for at least 5 years. An age-matched and sexmatched
control group of healthy nonsmokers was also recruited. Each participant
was subjected to a clinical psychiatric interview using the Arabic version of the
Mini-International Neuropsychiatric Interview. The chronotype of the participants was
evaluated using the Horne and Ostberg Morningness–Eveningness Questionnaire.
Cognition was assessed with the Montreal Cognitive Assessment scale. Smoking
status was assessed with the Fagerstro¨m Test for Nicotine Dependence, the selfadministered
Nicotine Dependence Syndrome Scale, and the Questionnaire of
Smoking Urges.
Results
The majority of smokers were of neither typology, followed by moderately evening type.
Smokers had statistically significant cognitive impairment in terms of visuospatial
ability, verbal fluency, delayed recording, and total Montreal Cognitive Assessment
score compared with nonsmokers. Sex affected chronotype, education, duration of
smoking, and Fagerstro¨m level of dependence scale score. Higher level of nicotine
dependence was associated with greater cognitive impairment in smokers.
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Journal: | Middle East Current Psychiatry 2016, 23:153–159 |
Text: | |
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