Specificity of verbal learning impairment and recovery in a marijuana-dependent male: The effects of sustained marijuana abstinence

Abstract

We present the case of a young adult in treatment for marijuana dependence, with recurrent depression and a history of possible TBI, complaining of concentration, memory and initiation problems. Testing at treatment baseline revealed performance that was generally in the High Average range on measures of reaction time and attention, with a selective impairment in verbal learning (Borderline to Extremely Low range). Following 8 weeks of abstinence from marijuana, his verbal learning recovered to expected levels (High Average range), with signs of improved learning strategy, efficiency, rate, and capacity. However, his reaction time and attention showed minimal evidence of change. This finding is consistent with the literature that demonstrates that marijuana-associated neurocognitive impairments may be specific to verbal learning and may remit with abstinence. The clinical implications of these case findings and recommendations for neuropsychological assessment of marijuana abusers are discussed.

Verbal learning in marijuana users seeking treatment: a comparison between depressed and non-depressed samples

“…The finding that verbal learning decrements were modestly associated with marijuana use is consistent with a considerable amount of literature demonstrating that: (i) verbal learning performance is decreased in active marijuana users (1,19,20), (ii) verbal learning performance is inversely correlated with severity measures of use (4,21), and (iii) verbal learning performance improves with increasing abstinence (22–24). However, the finding that verbal learning was not further decreased in participants with a comorbid depressive disorder was unexpected, considering that some studies have found that verbal memory function is decreased in non-marijuana-using depressed individuals (7,9,11).…”