Adolescent cannabis consumption and schizophrenia: Epidemiological and experimental evidences

Abstract

Marijuana is consistently the most widely used illicit drug among teenagers and most users first experiment it in adolescence. Adolescence is a critical period between childhood and adulthood, including not only reproductive maturation, but also cognitive, emotional and social maturation. In this period adolescent brain is still in transition differing anatomically and neurochemically from the adult's one. The endocannabinoid system is an important determinant for cerebral maturation, therefore its strong stimulation by the delta-9-tetrahydrocannabinol, that acts through the endocannabinoid system, might lead to subtle but lasting neurobiological changes that can affect adult brain functions and behaviour. We summarize the more recent researches investigating the relationships between adolescent exposure to cannabinoids and increased risk for psychotic disease such as schizophrenia, as highlighted by both human and animal studies. Epidemiological evidence suggests that cannabis use is a risk factor for schizophrenia, and an exacerbation of symptoms and worsening of the schizophrenic prognosis may occur in individuals with a predisposition for schizophrenia. The characteristic of adolescent brain probably makes it more vulnerable to cannabis effect producing psychotic like symptoms and possibly cause schizophrenia.