Prospective memory impairment in long-term opiate users.
BACKGROUND
Opiate use is associated with a range of neurological and cognitive deficits. However, to date, no studies have assessed whether these cognitive deficits extend to the ability to perform intended actions in the future (i.e. prospective memory). Reduced ability in this area might be anticipated due to impaired executive functions and episodic memory associated with long-term opiate use.


OBJECTIVE
The main objectives of this study are to assess the performance of long-term opiate users on a laboratory measure of prospective memory which closely simulates the types of prospective memory tasks encountered in everyday life ('Virtual Week') and to investigate the extent to which prospective memory performance is related to executive functions and episodic memory ability.


METHODS
Twenty-six long-term heroin users enrolled in an opiate substitution program, and 30 controls with no previous history of drug use were tested on Virtual Week. Retrospective memory and executive functions were also assessed.


RESULTS
Long-term opiate users were significantly impaired on prospective memory performance compared with controls (p = 0.002, η(2) p = 0.17), and these deficits did not vary as a function of prospective memory task type (regular, irregular, event, time). The findings also suggest that retrospective memory difficulties contribute to the prospective memory difficulties seen in opiate users (r s  = 0.78, p < 0.001) but that executive dysfunction is less influential.


CONCLUSIONS
Prospective memory is sensitive to long-term opiate use. Importantly, opiate users suffer from generalised deficits in prospective memory, regardless of the task demands, which may have significant implications for day-to-day functioning. These results may therefore contribute to the development of clinical intervention strategies to reduce the negative impact of prospective memory failures in daily life.
School of Psychology, Australian Catholic University, Melbourne Campus, Locked Bag 4115, Fitzroy, MDC, Melbourne, Victoria, 3065, Australia, gill.terrett@acu.edu.au.
Gill
G
Terrett
Skye N
SN
McLennan
Julie D
JD
Henry
Kathryn
K
Biernacki
Kimberly
K
Mercuri
H Valerie
HV
Curran
Peter G
PG
Rendell
D000328:Adult; D016022:Case-Control Studies; D056344:Executive Function; D006556:Heroin Dependence / Q000150:complications* / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000453:epidemiology / Q000209:etiology*; D061212:Memory, Episodic; D008875:Middle Aged; D058850:Opiate Substitution Treatment; D011597:Psychomotor Performance; D013997:Time Factors; D055815:Young Adult