The difference between the nonsensitized and sensitized states may be effectively the same as between individuals whose liability phenotypes differ: the threshold for use, contingent on social norms and perceived hedonic effects, is likely to be lower in an individual with high liability. In fact, if sensitization does occur, it is equivalent to an increase in individual liability at the level of neurochemical mechanisms of addiction. This is but one way by which the labile individual liability phenotype may fluctuate, as it does, for instance, when access to alcohol or drugs is attained or precluded, when peer pressure to use alcohol or drugs is experienced or ceases, or when stressful conditions motivate self-medication alcohol or drug use. The perceived hedonic benefit from drug use due to sensitization may or may not be a significant factor furthering drug use, wherein it may be combined with augmented access to drugs, decreased perception of danger and societal disapproval, and indeed with ignoring or approval of this behavior as normative—in certain social groups. Regardless of the role of sensitization, the probability of drug use
