Memory and Executive Function Deficits in Abstinent Patients with Methamphetamine Use Disorder

The use of methamphetamine is related to alterations in episodic memory, attention, executive functions, and information processing speed. Episodic memory disturbances in people who use methamphetamine have traditionally been related to a secondary problem with their executive functions. However, substantial evidence indicates that methamphetamine have neurotoxic effects on the hippocampus and alter encoding and consolidation memory processes. We aimed to determine whether people who use methamphetamine experience primary memory alterations or if their memory problems are due to executive function deficits. Additionally, we assessed their attention, executive functions, and processing speed. We administered a test of episodic memory with two lists (one presented semantically clustered and another presented randomized) to a group of 36 abstinent people who used methamphetamine and 31 healthy participants. Both groups were also assessed using the Attentional Network Test, the Stroop Color and Word Test, and the verbal fluency test. Our results showed that methamphetamine dependence might alter episodic memory consolidation, although the alteration of this cognitive function could also be due, in part, to executive functions deficits.