Investigating Sex-Specific Characteristics of Nicotine Addiction Using Metabolic and Structural Magnetic Resonance Imaging.

Nicotine addiction is known to modulate neurotransmission and alter the brain structure. The detrimental effect of nicotine is more prominent in females as compared to males. This study sought to examine the sex-specific influence of nicotine addiction on gamma amino butyric acid (GABA) and the white matter (WM) microstructure. Sixty healthy subjects (smokers/non-smokers) underwent structural and metabolic magnetic resonance imaging scans. Results showed alterations in WM integrity (measured as changes in fractional anisotropy [FA] and GABA in smokers versus non-smokers and females versus males. No overall significant smoking and sex-specific interactions were observed in this study. However, on comparing female smokers with female non-smokers, significantly higher GABA and FA values were observed in female smokers. However, GABA and FA values did not differ significantly when male smokers were compared against male non-smokers. Our results provide a further rationale to investigate the impact of nicotine on central GABAergic function and WM integrity, in particular due to the potential risk for females to experience depressive/anxiety symptoms during smoking cessation.