Some neuropsychological profiles of cannabis dependent users on long-term abstinence in a rehabilitation centre in Nigeria

The present study examined some neuropsychological profiles of cannabis dependent users on long abstinence in Nigeria. Ninety participants were recruited for the study. Their ages ranged from 27 – 35 years with a mean age of 30.78. Five neuropsychological instruments were used for the study: Symbol Digit Modality Test (SDMT), Digit Symbol Modality Test (DSMT), Trail Making Tests A & B (TMT – A/B), Rey Auditory Verbal Learning Test (RAVLT) and Rivermead Post Concussion Syndrome questionnaire (RPC). The findings of the study showed significant differences on verbal learning; RAVLT Trial 5: F(2,81) = 15.20, RAVLT Total Trial: F(2,81) = 11.06, Delayed verbal memory, F(2,81) = 10.94 all at P ≤ 0.05 level of testing with cannabis users performing worse than the psychiatric and healthy controls. Significant differences were also seen on processing speed: DSMT: F(2,81) = 3.53 with cannabis users performing worse than the healthy control but better than the psychiatric group. Drug users had significant less performance than the healthy control on TMT A; F(2,81) = 8.04 and TMT B; F(2,81) = 7.41 as measures of executive function. Also, drug users had significant worse complaints of somatic, cognitive and emotional symptoms following brain injury as measured by RPC; F(2,81) = 7.11 all at P ≤ 0.05 level of testing. Discussions of the study was based upon long term effects of cannabis use on neuro-cognition even after prolonged abstinence and reasons for the mixed findings surrounding this area of study. Implications of the study were also examined.Keywords: Neuro-cognition, Cannabis Users, Abstinence, Processing Speed, Memory