Abstract
Growing evidence indicates that adolescent substance abuse is now an alarming concern that imposes a considerable socio-economic burden on societies. On the other hand, numerous studies have shown that due to specific neurophysiological features, the brain is more vulnerable to the adverse effects of psychoactive drugs at an early age. Unfortunately, these negative effects are not limited to the period of drug use, but can persistently affect the brain's responsiveness to future exposures to the same or other types of drug. For researchers to develop pharmacological strategies for managing substance abuse disorders, they need to gain a deep understanding of the differences in behavioral outcomes associated with each type of drug across different age groups. The present study was conducted to review the experimental evidence revealing the mentioned differential effects with an emphasis on common drugs of abuse, including cocaine, nicotine, cannabis, and opioids. Although the cellular mechanisms underlying age-related effects have not been exclusively addressed for each drug, the most recent results are presented and discussed. Future studies are required to focus on these mechanisms and reveal how molecular changes during brain development can result in differential responses to drugs at the behavioral level.