To this study They did a recruitment of chronic cannabis usersto participate on the treatment at the Substance Use Disorder Program, FederalUniversity of Sao Paulo.
To be able to start treatment at UNIAD all individualshad to do interviews and provide complete medical and psychiatric history to determinateif they are eligible to participate or not. The criteria of selection were peoplebetween 18 to 55 years, male and female, with cannabis misuse or dependence,the person would be excluded if had history of other DSM-IV disorders, current useof psychoactive medications, history of head trauma with loss consciousness formore than 5 min, intellectual disability or IQ below 80, vision or hearingproblems and abstinence was encouraged but not mandatory. For this study theyalso recruited a control group (non-users), the criteria it was almost the sameinstead they couldn’t use any psychoactive substance, not use cannabis at allin the last 3 months or no been expose to more than 5 times. Although the participantssign a document accepting the terms and conditions of the study and theseinterviews took a day-long.Method The aim of this study is to do an analysis to executive functioningof people who used cannabis before age 15 9 (early -onset group) compared withthose who started after 15 (later-outset group) and control (non-users).
Thehypothesis is that the early-onset will perform worse on cognitive testsevaluating executive functioning comparative with later-outset and non- users.Consumption of cannabis/marijuana during adolescence caninfluence negatively neuromaturation and cognitive development. Even with weekof abstinence users of cannabis will show slower psychomotor speed, poorercomplex attention and memory skills and degraded planning/ sequencing abilitiescomparing with non-uses.
According with the studies these deficits can occur becauseafter birth the brain of the human been still developing, certain areas of thebrain like prefrontal cortex will develop in different times and just richmaturation around early 20’s. So, the environment will influence a lot the goodor bad development of the brain. These previous studies showed that being expose to cannabiscan cause neuropsychological deficits, even if the individual does some weeksof abstinence. They have another finding that this substance can be moreharmful to some individual than others, like people who is expose to neurotoxicsubstances before age of 15 have big possibilities of developing permanentneuropsychological deficits comparing with individual who started after age of15. Previous studies demonstrate that adolescence is avulnerable phase to neurocognitive effects related to substance misuse but notthat much studies has been made, to measure differences in cognitive performancebetween an individual who started before age of 15 with those who started later.