Subjective responses to initial experience with cocaine: an exploration of the incentive-sensitization theory of drug abuse.
OBJECTIVE
This study investigated the relationship between positive and negative subjective responses at the time of initial cocaine use with adult cocaine dependence and life-time use rates. Psychostimulant pre-exposure, regular smoking or stimulant treatment before initiation were examined to explore the incentive sensitization theory of addiction.


METHODS
A total of 202 adult participants who had tried cocaine on at least one occasion were studied prospectively from childhood into adulthood. The cocaine-initiated group included 89 who met Diagnostic and Statistical Manual version IV (DSM-IV) criteria for attention deficit hyperactive disorder (ADHD) and 113 age-matched controls.


METHODS
Five childhood and three adulthood interviews provided data on ages of initiation into cocaine and life-time use of cocaine from ages 16-40 years. Correlations of each subjective response and analyses of variance (ANOVAs) of cocaine 'liking' and 'wanting' with DSM-III-R cocaine dependence and life-time use provided support for the validity of the measures. ANOVA provided evidence of the effect of psychostimulant pre-exposure on 'liking' and 'wanting'. Logistic regression modeled the prediction of dependence and life-time use with the independent variables of 'liking' and 'wanting', psychostimulant pre-exposure and participant characteristics.


RESULTS
When cocaine was first tried, 'liking' and 'wanting' were significant predictors of cocaine dependence and life-time use. Mean 'liking' or 'wanting' responses did not differ by participant characteristics. Those who were pre-exposed by regular smoking or stimulant treatment had higher 'liking' and 'wanting' scores; but participants who were pre-exposed by both stimulant treatment and regular smoking reported the lowest liking and the highest wanting responses, consistent with the incentive sensitization theory. Logistic regression showed that the 'liking' and 'wanting' responses increased significantly the odds of DSM-III-R cocaine dependence and life-time use.


CONCLUSIONS
In this sample, subjective 'liking' and 'wanting' measured risk for cocaine abuse.
Lambert
Nadine M
NM
University of California at Berkeley, 94720, USA. nlambert@socrates.berkeley.edu
McLeod
Marsha
M
Schenk
Susan
S