| Publication Abstract Display | | Type: Published Abstract | | Title: Effects of cannabis use on the cognitive performance of methamphetamine dependent individuals. | | Authors: Gonzalez R, Carey C, Moore DJ, Schweinsburg BC, Rippeth J, Heaton RK, Cherner M, Grant I, and the HNRC Group | | Year: 2002 | | Publication: Journal of the International Neuropsychological Society | | Volume: 8 Issue: 2 Pages: 287-288 | | Abstract:Neuropsychological (NP) performance was compared between 3 groups: (1) subjects with a history of methamphetamine dependence (Meth) and history of cannabis abuse/dependence (M+C+, n=47); (2) Meth dependent subjects without history of cannabis abuse/dependence (M+C-, n=25); (3) a control group (M-C-, n=52). The 3 groups did not differ significantly on ethnicity and age. Statistically significant differences, albeit small, were observed on years of education and sex. The 2 M+ groups were comparable in terms of demographics, psychiatric comorbidity, and Meth use. A comprehensive NP battery was administered, and demographically corrected T-scores were obtained for each measure. T-scores on NP tests were averaged within each of 5 ability areas: Verbal Fluency, Learning, Memory/Retention (M/R), Processing Speed/Working Memory, and Motor Skills. Planned orthogonal contrasts were used to specify if NP performance differed (1) between both M+ groups against the M-C- group and (2) between the M+C+ group and the M+C- group. The M+ groups differed from the M-C- group on average T-scores for tests of Learning (t(71) = 23.20, p < .01) and M/R (t(71) = 22.33, p = .02). The M+C+ group performed significantly better than the M+C- group on tests of M/R (t(71) = 2.22, p = .03). Although not significantly different, blind clinical ratings of NP performance showed greater rates of impairment in the M+C- group for all but 1 of the ability areas rated, when compared to the M+C+ group. These preliminary data suggest that cannabis use may modify the effects of Meth on NP performance by attenuating Meth induced NP impairment. More complex study designs and additional evidence regarding the neuromechanisms of cannabis are necessary to clarify if its role is indeed neuroprotective in this population. |
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