Subjects

This cross-sectional study was conducted in the Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia during the period Nov 2015 to May 2016. We matched subjects by age, sex, ethnicity, and socioeconomic status to estimate the impact of cigarette smoking on cognitive functions.

A detailed interview of the participants was conducted for study enrollment. All participants were questioned regarding cigarette smoking and use of other tobacco products. We excluded subjects based on a detailed history obtained regarding any drug intake, diseases such as seizures, and psychiatric problems.

Our study had 2 groups. The smoking group consisted of 22 male volunteers, with mean age 24.4±5.30 (Mean ±SD) years who were considered as regular cigarette smokers for at least 1 year and who smoked at least 1 cigarette per day. These 22 cigarette smokers were matched with a group of 30 non-cigarette smokers (control) who had never smoked, who were healthy male volunteers with mean age 23.31±2.68 (Mean ±SD) and were matched with the smoking group for age, sex, ethnicity, and socioeconomic status. This control group primarily consisted of university students, as well as technicians, secretaries, research assistants, and receptionists. The Institutional Review Board, King Khalid University Hospital and College of Medicine, King Saud University, approved the study.