Effects of Cannabis Use on Brain Development The Fontes, et al. (2011) study investigated the effects of cannabis use on brain development before and after attaining the age of 15 years. The authors referred to several scholars who have in the past investigated these relationships, and they indicate that most of these studies suggest that puberty is a stage of significant vulnerability to neurocognitive effects linked to substance abuse. However, the authors point out that few important studies have endeavoured to measure the disparities in cognitive performance involving chronic users of cannabis who begun using cannabis before attaining the age of 15 years, with chronic users who started after attaining the age of 15.
Longitudinal, as well as cross-sectional structural brain imaging research have demonstrated that the brain, prior to the attainment of 15 years of age, is under a complicated course of biological maturation. The rationale of the study by Fontes, et al. (2011) was to investigate the executive functioning of persons who began chronic abuse of cannabis before attaining the age of 15, compared with those who started chronic use of cannabis after attaining the age of 15. According to Fontes, et al.
(2011), while several studies have established neuropsychological deficits linked to chronic cannabis exposure, there are outcomes from studies investigating recurrent cognitive impairments linked to chronic cannabis that depict contradictory viewpoints. The authors continue to assert that some studies demonstrate that even after practicing abstinence, chronic cannabis users may continue to experience considerable neuropsychological deficits. The authors explain that these conflicting findings may be based on the premise that the neurotoxic effects of cannabis differ among populations. In this regard, when persons of less than 15 years of age are exposed to substances that are potentially neurotoxic, they become more liable to develop recurrent neuropsychological deficits, in comparison to older persons. Fontes, et al. (2011) asserts that adolescents are susceptible to defective cognitive effects related to the abuse of cannabis.
The authors allege that results from diverse studies imply that chronic users of cannabis process complicated information significantly slowly, while performance deteriorates in cognitive overload responsibilities as lifetime use increases. It is in this context that Fontes, et al. (2011) investigated the effect on executive functioning among 104 chronic users of cannabis. While focusing on executive functioning, the group was divided in two cohorts, where 49 individuals were chronic users in the early-onset category and 55individuals, late-onset chronic users, as well as 44 healthy controls that carried out neuropsychological responsibilities. The control group involved individuals who had not abused cannabis in the previous 3 months, and less than 5 times in their lifetime.
Comparisons concerning neuropsychological measures were carried out through a generalised linear model analysis of variance (ANOVA). These chronic users of cannabis were initially under care at the Substance Use Disorder Program, Federal University of Sao Paulo. In the study, Fontes, et al. (2011) held the hypothesis that the early-onset group (prior to 15 years of age) was likely to exhibit poor performance in cognitive tests that evaluate executive functioning , in comparison to the late-onset group (after 15 years of age), and the healthy controls. The inclusion criteria employed for chronic users of cannabis was males and females, between 18 and 55 years of age, exhibiting DSM-IV cannabis abuse or addiction as stipulated by the Composite International Diagnostic Interview (CIDI). The criteria for exclusion entailed present record of other DSM-IV Axis I disorders, excluding nicotine-related disorders as stipulated by CIDI; present usage of psychoactive drugs, record of head trauma with seizures for above 5 minutes, intellectual incapacity or approximate IQ less than 80, as well as irreparable hearing, vision or injury. Persons in the control group were eligible for the study on condition that they were between 18 and 55 years of age, and did not abuse psychoactive substances, did not hold a record of head trauma, and never diagnosed with Axis I DSM-IV disorders in their lifetime.
The study’s protocol was endorsed by the local institutional review board, while the respondents were under obligation to consent in writing, in line with the Federal University of Sao Paulo review board. The study findings point out that the early onset cohort are cognitively impaired in relation to controls, implying that early use of cannabis is linked to negative impact on the brain. These outcomes correspond to preceding studies that investigated cognitive effects linked to early exposure to cannabis. The study did not establish disparities in executive functioningperformance between the late-onset cohort and the healthy cohort. In conclusion, the study findings imply that early-onset chronic users of cannabis but notdisplay executive deficits, while the contrary is the case in the late-onset group. While the fundamental mechanisms may not be entirely understood, it is apparent that exposure to cannabis at an early age might hold more significant detrimental impact on neurocognitive functioning.