Exposure to cannabis during adolescence is associated with increased risky and impulsive decision making, with users adopting strategies with higher levels of uncertainty and inefficient utilisation of information. The young cannabis users did show sensitivity to losses, suggesting that greater impulsivity early in their drug using career is more evident when there is a lack of negative consequences. This provides a window of opportunity for intervention before the onset of cannabis dependence.

These findings indicate that chronic use of cannabis may impair the brain's ability to respond optimally in the presence of events that require conflict resolution and hold implications for the ability to refrain from substance misuse and/or maintain substance abstention behaviours.

Pharmaceutical Benefits Scheme claims represent a significant resource to examine Australia's billion-dollar annual investment in prescribed medicines. The body of research is growing and has increased in complexity over time. Australia has great potential to undertake world-class, whole-of-population pharmacoepidemiological studies. Recent investment in data linkage infrastructure will significantly enhance these opportunities.

No abstract

Objective: Evidence that cannabis use impairs cognitive function in humans has been accumulating in recent decades. The purpose of this overview is to update knowledge in this area with new findings from the most recent literature. Method: Literature searches were conducted using the Web of Science database up to February 2010. The terms searched were: "cannabi*" or "marijuana", and "cogniti*" or "memory" or "attention" or "executive function", and human studies were reviewed preferentially over the animal literature. Discussion: Cannabis use impairs memory, attention, inhibitory control, executive functions and decision making, both during the period of acute intoxication and beyond, persisting for hours, days, weeks or more after the last use of cannabis. Pharmacological challenge studies in humans are elucidating the nature and neural substrates of cognitive changes associated with various cannabinoids. Long-term or heavy cannabis use appears to result in longer-lasting cognitive abnormalities and possibly structural brain alterations. Greater adverse cognitive effects are associated with cannabis use commencing in early adolescence. Conclusion: The endogenous cannabinoid system is involved in regulatory neural mechanisms that modulate processes underlying a range of cognitive functions that are impaired by cannabis. Deficits in human users most likely therefore reflect neuroadaptations and altered functioning of the endogenous cannabinoid system. ResumoObjetivo: Evidências de que o uso de cannabis prejudica funções cognitivas em humanos têm-se acumulado nas décadas recentes. O propósito desta revisão é o de atualizar o conhecimento nesta área com novos achados a partir da literatura mais recente. Método: As buscas na literatura foram realizadas utilizando-se o banco de dados Web of Science até fevereiro de 2010. Foram buscados os termos "cannabi*" ou "marijuana" e "cogniti*" ou "memory" ou "attention" ou "executive function", e os estudos em humanos foram revisados preferencialmente em relação aos estudos em animais. Discussão: O uso de cannabis prejudica a memória, a atenção, o controle inibitório, as funções executivas e a tomada de decisões, tanto durante como após o período de intoxicação aguda, persistindo por horas, dias, semanas ou mais após o último uso. Os estudos de desafio farmacológico em humanos estão elucidando a natureza e os substratos neurais das alterações cognitivas associadas a vários canabinoides. O uso pesado ou de longo prazo de cannabis parece resultar em anormalidades cognitivas mais duradouras e possivelmente em alterações cerebrais estruturais. Efeitos cognitivos adversos maiores estão associados ao uso de cannabis quando este começa no início da adolescência. Conclusão: O sistema canabinoide endógeno está envolvido nos mecanismos de regulação neural que modulam os processos subjacentes a uma gama de funções cognitivas que estão prejudicadas pela cannabis. Os déficits em usuários humanos muito provavelmente refletem, portanto, neuroadaptações e o funcionamento alterado do sistema ca...