[The influence of social stress on the reinforcing effect of ecstasy under the conditioned place preference paradigm: the role played by age, dose and type of stress].

INTRODUCTION: Addiction to drugs is a chronic illness with severe repercussions for those that consume them and to date has no known cure. Psychostimulants, such as ecstasy, are the most widely consumed illegal drugs among adolescents and young adults.

AIMS: To describe and to analyse the different variables that can influence the effects of social stress and the reinforcing properties of ecstasy. Likewise, it also seeks to evaluate whether the effects of social stress on conditioned place preference (induced by ecstasy) are similar to those deriving from other psychostimulants, such as cocaine.

DEVELOPMENT: Social defeat evaluated in the short term has an effect only on adult animals by diminishing sensitivity to the conditioned reinforcing effects of ecstasy. Conversely, long-term social stress increases the reinforcing effects of this drug in adolescent and adult animals. The dose of ecstasy employed has little influence on the effects of social defeat on conditioned place preference. In comparison to the effects of social stress on the reinforcing properties of cocaine, a different effect is only observed when defeat is evaluated in the short term.

CONCLUSIONS: Different variables modulate the reinforcing effects of ecstasy, such as the age of the animals, the dose employed or exposure to stress. It is essential to study these variables in order to determine the neurobiological and environmental vulnerability factors that can have an influence on the development of addiction to ecstasy.