Sex-Specific Mediation of Pre-Quit Smoking Reduction: Secondary Analysis of a Randomized Controlled Trial Extending Varenicline Preloading. - Johnstone S; Cooper RK; Wray JM; Tonkin S; Knapp KS; Colder CR; Maguin E; Mahoney MC; Tiffany ST; Brandon TH; Ashare RL; Hawk LW Jr (Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco, 2025)