In addition to the effects of rate of BrAC change, subjective responses to alcohol are known to adapt over time. The development of chronic tolerance to alcohol is one of the hallmarks of increased severity of an alcohol use disorder (AUD). To the degree that the capacity for developing chronic tolerance is reflected in acute, i.e. within-session, tolerance, the phenomenon can be studied in laboratory paradigms that assess changes in alcohol effects during one exposure to alcohol. One approach for assessing acute tolerance to alcohol, attributed to Mellanby (Mellanby, 1919, as described in Martin and Moss, 1993) is to measure some assay of alcohol’s effects on the ascending limb of exposure, and at the same blood alcohol concentration on the descending limb, with differences in the magnitude of the effect attributed to acute tolerance or acute sensitization. For example, Portans (Portans et al., 1989) inferred acute tolerance to alcohol when subjects reported greater subjective effects on the ascending limb of the BrAC curve, compared to effects at a comparable BrAC on the descending limb. Alternatively, the magnitude of the effect
