Semantic priming and verbal learning in current opiate users, ex-users and non-user controls.

OBJECTIVE

Despite a growing interest in memory functions of chronic drug users, investigation of semantic and episodic memory in opiate users is limited, and findings of studies have been inconsistent. The present study aimed to assess semantic memory and episodic memory for both drug-related and neutral stimuli in current and ex-users of opiates.

METHODS

Using an independent group design, we assessed semantic priming and verbal learning in 16 current opiate users on a methadone maintenance programme, 16 ex-opiate users in rehabilitation programmes and 16 healthy controls. The groups were matched on verbal IQ, age and employment status.

RESULTS

We found that current and ex-users showed intact automatic and controlled semantic priming. Ex-users who had been abstinent for an average of 19 months showed a verbal learning impairment compared with controls. Both current and ex-users were impaired in recalling semantically unrelated words but unimpaired in recalling semantically related words.

CONCLUSION

The findings suggest a relative lack of spontaneous use of mnemonic strategies and imply that highly structured information would help opiate-using clients in treatment.