RATIONALE: Ketamine is an N-methyl-d-aspartate (NMDA)-receptor antagonist that is increasingly being used as a recreational drug. Previous research has shown gross generalised verbal memory impairments persisting 3 days after ketamine use in chronic users, however episodic memory has not specifically investigated in this population. OBJECTIVE: To determine whether ketamine, on the night of drug use (day 0) and 3 days later, is associated with impaired episodic memory as assessed by a source memory task. METHODS: Twenty ketamine users and 20 poly-drug controls were compared on a source memory task both on day 0 and 3. Participants also completed questionnaires on both days indexing schizophrenic-like and dissociative symptoms. RESULTS: On day 0, ketamine abusers were impaired on both source memory and item recognition and scored more highly on schizophrenic and dissociative symptom scales compared to poly-drug controls. On day 3 ketamine abusers only displayed source memory impairments and these positively correlated with the level of schizophrenic-like symptoms on day 0. No differences on day 3 in schizophrenic-like or dissociative symptoms were observed. CONCLUSIONS: Ketamine abusers exhibit a persisting deficit in source memory on day 3 but not in item recognition. These findings suggest that repeated use of ketamine produces chronic impairments to episodic memory.
RATIONALE: Ketamine is an N-methyl-d-aspartate (NMDA)-receptor antagonist that is increasingly being used as a recreational drug. Previous research has shown gross generalised verbal memory impairments persisting 3 days after ketamine use in chronic users, however episodic memory has not specifically investigated in this population. OBJECTIVE: To determine whether ketamine, on the night of drug use (day 0) and 3 days later, is associated with impaired episodic memory as assessed by a source memory task. METHODS: Twenty ketamine users and 20 poly-drug controls were compared on a source memory task both on day 0 and 3. Participants also completed questionnaires on both days indexing schizophrenic-like and dissociative symptoms. RESULTS: On day 0, ketamine abusers were impaired on both source memory and item recognition and scored more highly on schizophrenic and dissociative symptom scales compared to poly-drug controls. On day 3 ketamine abusers only displayed source memory impairments and these positively correlated with the level of schizophrenic-like symptoms on day 0. No differences on day 3 in schizophrenic-like or dissociative symptoms were observed. CONCLUSIONS:Ketamine abusers exhibit a persisting deficit in source memory on day 3 but not in item recognition. These findings suggest that repeated use of ketamine produces chronic impairments to episodic memory.
Authors: Lawrence P Carter; Bethea A Kleykamp; Roland R Griffiths; Miriam Z Mintzer Journal: Psychopharmacology (Berl) Date: 2012-10-25 Impact factor: 4.530