Social isolation at adolescence: a systematic review on behaviour related to cocaine, amphetamine and nicotine use in rats and mice

Adolescence is known for its high level of risk-taking, and neurobiological alterations during this period may predispose to psychoactive drug initiation and progression into more severe use patterns. Stress is a risk factor for drug consumption, and post-weaning social isolation increases drug self-administration in rodents. This review aimed to provide an overview of the effects of adolescent social isolation on cocaine, amphetamine and nicotine use-related behaviours, highlighting the specific period when animals were submitted to stress and these drugs. We wondered if there was a specific period during adolescence that isolation stress would increase drug use vulnerability. A total of 323 publications from the Scopus, Web of Science and PubMed (Medline) electronic databases were identified using the words "social isolation" and "adolescence" and "drug" or "cocaine" or "amphetamine" or "nicotine", resulting in 24 articles after analyses criteria following the PRISMA statement. The main points raised were social isolation during adolescence increased cocaine self-administration, amphetamine and nicotine locomotor activity. We did not observe a pattern of a specific moment during the adolescent period that could lead to an increased vulnerability to drug use. The precise conditions under which adolescent social stress alters drug use parameters are complex and likely depend on several factors.