Mice from each genotype received four cycles of chronic intermittent ethanol (CIE) vapor exposure (CIE group, B–D–F) or air exposure (CTL group, A– C–E) (16 h/day × 4 days, followed by 72-h withdrawal), alternated with 5-day drinking test cycles using a two-bottle (15% v/v ethanol vs. water) limited access (2 h/day) drinking model. Blood samples for neuroactive steroid assays were collected 72 h after a fifth CIE or air exposure cycle. Neuroactive steroid levels, assayed in all male and female cases, are expressed as pg/mL and are means ± SEM of values from 2–16 mice/strain/treatment. The x-axis reports the BXD strain number; C57BL/6J and DBA/2 are also indicated (black bars). Strains are plotted in order from the lowest to the highest levels for each of the neuroactive steroids. One-way ANOVA was used to estimate significant variation.