Roebke PV, Vadhan NP, Brooks DJ, Levin FR. Verbal learning in marijuana users seeking treatment: a comparison between depressed and non-depressed samples.
THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2014;
40:274-9. [PMID:
24918839 DOI:
10.3109/00952990.2013.875551]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND
Both individuals with marijuana use and depressive disorders exhibit verbal learning and memory decrements.
OBJECTIVES
This study investigated the interaction between marijuana dependence and depression on learning and memory performance.
METHODS
The California Verbal Learning Test-Second Edition (CVLT-II) was administered to depressed (n = 71) and non-depressed (n = 131) near-daily marijuana users. The severity of depressive symptoms was measured by the self-rated Beck Depression Inventory (BDI-II) and the clinician-rated Hamilton Depression Rating Scale (HAM-D). Multivariate analyses of covariance statistics (MANCOVA) were employed to analyze group differences in cognitive performance. Pearson's correlation coefficients were calculated to examine the relative associations between marijuana use, depression and CVLT-II performance. Findings from each group were compared to published normative data.
RESULTS
Although both groups exhibited decreased CVLT-II performance relative to the test's normative sample (p < 0.05), marijuana-dependent subjects with a depressive disorder did not perform differently than marijuana-dependent subjects without a depressive disorder (p > 0.05). Further, poorer CVLT-II performance was modestly associated with increased self-reported daily amount of marijuana use (corrected p < 0.002), but was not significantly associated with increased scores on measures of depressive symptoms (corrected p > 0.002).
CONCLUSION
These findings suggest an inverse association between marijuana use and verbal learning function, but not between depression and verbal learning function in regular marijuana users.
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