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

Abstract

Introduction. We present the case of a young adult in treatment for marijuana dependence, with recurrent depression and a history of possible traumatic brain injury, complaining of concentration, memory, and initiation problems.

Methods. The patient was assessed longitudinally during treatment with a brief neuropsychological battery, as well as measures of marijuana use and mood.

Results. Testing at treatment baseline revealed performance that was generally in the high average range or higher 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.

Conclusions. This finding is consistent with the literature that demonstrates that marijuana-associated neurocognitive impairments may be most pronounced in the domain of verbal learning and may remit with abstinence. The clinical implications of these case findings and recommendations for neuropsychological assessment of marijuana abusers are discussed.

Keywords:

• Abstinence
• California Computerised Assessment Package
• California Verbal Learning Test
• Depression
• Marijuana
• Verbal learning

Acknowledgements

This research was supported by NIDA grants K02 000465 and R01 015451-05 to FRL and K01 019933 to NPV. The authors gratefully acknowledge Patrick Roebke, Eliezer Pickholtz, Elysia Michaels, and Olivia Wu for their assistance in preparation of this report.

Notes

¹A “blunt” is a cigar filled with marijuana, generally equivalent to three typical marijuana cigarettes or “joints”.

²The patient and clinical staff judged the patient's current depressive episode to be marijuana related. However, marijuana is not recognised by DSM-IV as a substance that can induce depression; hence, the primary mood disorder diagnosis.

³AMIPB = Adult Memory and Information Processing Battery (Coughlan & Hollows, 1985).