This text was adapted by The Saylor Foundation under a Creative Commons Attribution-NonCommercial-ShareAlike 0 License without attribution as requested by the work’s original creator or licensee. Preface

Psychological Explanations

Psychological explanations join biological explanations in focusing on why certain individuals are more likely than others to use drugs and to be addicted to drugs (Hanson et al., 2012). ^[2] Some popular psychological explanations center on personality differences between drug users and nonusers. These explanations assume that users have personality traits that predispose them to drug use. These traits include low self-esteem and low self-confidence, low trust in others, and a need for thrills and stimulation. In effect, drug users have inadequate personalities, or personality defects, that make them prone to drug use, and once they start using drugs, their personality problems multiply.

One problem with research on personality explanations is methodological: If we find personality differences between drug users and nonusers, should we conclude that personality problems cause drug use, or is it possible that drug use causes personality problems? Most of the research on personality and drug use cannot answer this question adequately, since it studies drug users and nonusers at one point in time (cross-sectional research). To answer this question adequately, longitudinal research, which examines the same people over time, is necessary. Among initial drug abstainers at Time 1, if those with the personality traits mentioned earlier turn out to be more likely than those without the traits to be using drugs at Time 2, then we can infer that personality problems affect drug use rather than the reverse. Longitudinal research on personality and drug use that studies adolescents and college students does indeed find this causal sequence (Sher, Bartholow, & Wood, 2000). ^[3] However, some scholars still question the importance of personality factors for drug use and addiction (Goode, 2012). ^[4] They say these factors have only a small effect, if that, and they cite research questioning whether personality differences between users and nonusers in fact exist (Feldman, Boyer, Kumar, & Prout, 2011). ^[5]

Other psychological explanations are based on the classic concept from behavioral psychology of operant conditioning—the idea that people and animals are more likely to engage in a behavior when they are rewarded, or reinforced, for it. These explanations assume that people use drugs because drugs are positive reinforcers in two respects. First, drugs provide pleasurable effects themselves and thus provide direct reinforcement. Second, drug use often is communal: People frequently use drugs (alcohol is certainly a prime example, but so are many other drugs) with other people, and they enjoy this type of social activity. In this manner, drug use provides indirect reinforcement.