RESUMO
BACKGROUND: Many studies have suggested that adolescence is a period of particular vulnerability to neurocognitive effects associated with substance misuse. However, few large studies have measured differences in cognitive performance between chronic cannabis users who started in early adolescence (before age 15) with those who started later. AIMS: To examine the executive functioning of individuals who started chronic cannabis use before age 15 compared with those who started chronic cannabis use after 15 and controls. METHOD: We evaluated the performance of 104 chronic cannabis users (49 early-onset users and 55 late-onset users) and 44 controls who undertook neuropsychological tasks, with a focus on executive functioning. Comparisons involving neuropsychological measures were performed using generalised linear model analysis of variance (ANOVA). RESULTS: The early-onset group showed significantly poorer performance compared with the controls and the late-onset group on tasks assessing sustained attention, impulse control and executive functioning. CONCLUSIONS: Early-onset chronic cannabis users exhibited poorer cognitive performance than controls and late-onset users in executive functioning. Chronic cannabis use, when started before age 15, may have more deleterious effects on neurocognitive functioning.
Assuntos
Desenvolvimento do Adolescente/efeitos dos fármacos , Canabinoides/efeitos adversos , Transtornos Cognitivos/induzido quimicamente , Função Executiva/efeitos dos fármacos , Abuso de Maconha/complicações , Adolescente , Adulto , Fatores Etários , Idade de Início , Análise de Variância , Encéfalo/efeitos dos fármacos , Encéfalo/crescimento & desenvolvimento , Canabinoides/administração & dosagem , Criança , Transtornos Cognitivos/epidemiologia , Estudos Transversais , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Abuso de Maconha/epidemiologia , Pessoa de Meia-Idade , Testes Neuropsicológicos/estatística & dados numéricos , Adulto JovemRESUMO
BACKGROUND: Cannabis is the most used illicit drug in the world, and its use has been associated with prefrontal cortex (PFC) dysfunction, including deficits in executive functions (EF). Considering that EF may influence treatment outcome, it would be interesting to have a brief neuropsychological battery to assess EF in chronic cannabis users (CCU). In the present study, the Frontal Assessment Battery (FAB), a brief, easy to use neuropsychological instrument aimed to evaluate EF, was used to evaluate cognitive functioning of CCU. METHODS: We evaluated 107 abstinent CCU with the FAB and compared with 44 controls matched for age, estimated IQ, and years of education. RESULTS: CCU performed poorly as compared to controls (FAB total score = 16.53 vs. 17.09, p < .05). CCU had also a poor performance in the Motor Programming subtest (2.47 vs. 2.73, p < .05). CONCLUSION: This study examined effects of cannabis in executive functioning and showed evidence that the FAB is sensitive to detect EF deficits in early abstinent chronic cannabis users. Clinical significance of these findings remains to be investigated in further longitudinal studies. FAB may be useful as a screening instrument to evaluate the necessity for a complete neuropsychological assessment in this population.
Assuntos
Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Função Executiva/fisiologia , Lobo Frontal/fisiopatologia , Fumar Maconha/fisiopatologia , Adulto , Feminino , Fosfolipases A2 do Grupo II , Humanos , Inibição Psicológica , Idioma , Testes de Linguagem , Masculino , Testes Neuropsicológicos , Autonomia Pessoal , Desempenho Psicomotor/fisiologia , Adulto JovemRESUMO
OBJECTIVE: Cannabis is the most used illicit drug worldwide, however only a few studies have examined cognitive deficits related to its use. Clinical manifestations associated with those deficits include a motivational syndrome, impairment in cognitive flexibility, inattention, deficits in abstract reasoning and concept formation, aspects intimately related to the executive functions, which potentially exert a central role in substance dependence. The objective was to make a review about consequences of cannabis use in executive functioning. METHOD: This review was carried out on reports drawn from MedLine, SciELO, and Lilacs. DISCUSSION: In studies investigating acute use effects, higher doses of tetrahydrocannabinol are associated to impairments in performance of nonsevere users in planning and control impulse tasks. However, chronic cannabis users do not show those impairments. Although demonstration of residual effects of cannabis in the executive functioning is controversial, persistent deficits seem to be present at least in a subgroup of chronic users after 28 days of abstinence. CONCLUSIONS: The neuropsychological studies found did not have as a main aim the evaluation of executive functioning. A criterial selection of standardized neuropsychological tests, more appropriate study designs as well as concomitant investigations with structural and functional neuroimaging techniques may improve the understanding of eventual neurotoxicity associated with cannabis use.
Assuntos
Canabinoides/farmacologia , Transtornos Cognitivos/induzido quimicamente , Cognição/efeitos dos fármacos , Abuso de Maconha/psicologia , Fumar Maconha/efeitos adversos , Atenção/efeitos dos fármacos , Transtornos Cognitivos/fisiopatologia , Formação de Conceito/efeitos dos fármacos , Tomada de Decisões , Dronabinol/toxicidade , Lobo Frontal/efeitos dos fármacos , Humanos , Comportamento Impulsivo/induzido quimicamente , Comportamento Impulsivo/fisiopatologia , Comportamento Impulsivo/psicologia , Fumar Maconha/fisiopatologia , Fumar Maconha/psicologia , Testes NeuropsicológicosRESUMO
OBJETIVO: A maconha é a droga ilícita mais consumida no mundo, porém ainda existem poucos estudos examinando eventuais prejuízos cognitivos relacionados ao seu uso. As manifestações clínicas associadas a esses déficits incluem síndrome amotivacional, prejuízo na flexibilidade cognitiva, desatenção, dificuldade de raciocínio abstrato e formação de conceitos, aspectos intimamente ligados às funções executivas, as quais potencialmente exercem um papel central na dependência de substâncias. O objetivo do estudo foi fazer uma revisão a respeito das implicações do uso da maconha no funcionamento executivo. MÉTODO: Esta revisão foi conduzida utilizando-se bases de dados eletrônicas (MedLine, Pubmed, SciELO and Lilacs). DISCUSSÃO: Em estudos de efeito agudo, doses maiores de tetrahidrocanabinol encontram-se associadas a maior prejuízo no desempenho de usuários leves em tarefas de controle inibitório e planejamento; porém, este efeito dose-resposta não ocorre em usuários crônicos. Embora haja controvérsias no que se refere a efeitos residuais da maconha, déficits persistentes parecem estar presentes após 28 dias de abstinência, ao menos em um subgrupo de usuários crônicos. CONCLUSÕES: Os estudos encontrados não tiveram como objetivo principal a avaliação das funções executivas. A seleção de testes padronizados, desenhos de estudos mais apropriados e o uso concomitante com técnicas de neuroimagem estrutural e funcional podem auxiliar na melhor compreensão das conseqüências deletérias do uso crônico da maconha no funcionamento executivo.
OBJECTIVE: Cannabis is the most used illicit drug worldwide, however only a few studies have examined cognitive deficits related to its use. Clinical manifestations associated with those deficits include amotivational syndrome, impairment in cognitive flexibility, inattention, deficits in abstract reasoning and concept formation, aspects intimately related to the executive functions, which potentially exert a central role in substance dependence. The objective was to make a review about consequences of cannabis use in executive functioning. METHOD: This review was carried out on reports drawn from MedLine, SciELO, and Lilacs. DISCUSSION: In studies investigating acute use effects, higher doses of tetrahydrocannabinol are associated to impairments in performance of nonsevere users in planning and control impulse tasks. However, chronic cannabis users do not show those impairments. Although demonstration of residual effects of cannabis in the executive functioning is controversial, persistent deficits seem to be present at least in a subgroup of chronic users after 28 days of abstinence. CONCLUSIONS: The neuropsychological studies found did not have as a main aim the evaluation of executive functioning. A criterial selection of standardized neuropsychological tests, more appropriate study designs as well as concomitant investigations with structural and functional neuroimaging techniques may improve the understanding of eventual neurotoxicity associated with cannabis use.