Preference for oral MDPV solutions in a continuous access two-bottle choice procedure where the alternative fluid was water following a 0 day (black bars), 3 day (light gray bars) or 10 day (dark gray bars) history of 0.30 mg/mL MDPV consumption in a forced-choice setting. Mean total MDPV intake for the 3 day history group was 3.57±0.39 mg, and was 11.39±0.73 mg for the 10 day history group. Abscissa: MDPV concentration expressed as mg/mL on a log scale. Ordinate: Mean MDPV preference score (mL MDPV solution consumed/mL total fluid consumption, expressed as a %). Asterisks indicate significant differences from 0 day MDPV history, within dose. Dashed horizontal lines at 25% and 75% indicate thresholds for preference for the alternative fluid and preference for the MDPV solution, respectively.