Adverse effects of chronic marijuana use on learning, memory, and cognition are of serious concern in view of the widespread use of this drug, especially as use has extended into progressively younger age groups in recent years. Surprisingly, although acute impairment of memory from single marijuana doses has been frequently demonstrated, experimental studies of chronic marijuana effects on learning, memory, and cognition have been few in number, methodologically weak, and ambiguous in outcome. The first portion of the proposed study will examine effects of chronic illicit marijuana use by comparing """"""""heavy"""""""" chronic users, """"""""light"""""""" chronic users, and non-users matched on intellectual functioning before the onset of marijuana use. Under non-drug conditions, laboratory tests that emphasize learning and remembering new information, concept formation, associative processes, semantic memory retrieval, and psychomotor performance will be administered together will standardized tests that emphasize utilization of previously (pre-experimentally) acquired information. The study will determine whether chronic marijuana users are impaired relative to matched non-users on these tests and, if so, whether the impairments depend on the frequency of chronic marijuana use. In a subsequent portion of the study, the same tests will be administered following smoking of active or placebo marijuana to determine whether the sensitivity of individual test to chronic marijuana use corresponds with their sensitivity to acute effects of marijuana.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA003988-02
Application #
3208918
Study Section
(SRCD)
Project Start
1987-09-30
Project End
1990-08-31
Budget Start
1988-09-01
Budget End
1989-08-31
Support Year
2
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Iowa
Department
Type
Schools of Medicine
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Block, Robert I (2006) Methods for studying acute and chronic effects of marijuana on human associative processes and memory. Methods Mol Med 123:217-34
Block, Robert I; Erwin, Wesley J; Ghoneim, M M (2002) Chronic drug use and cognitive impairments. Pharmacol Biochem Behav 73:491-504
Block, R I; Erwin, W J; Farinpour, R et al. (1998) Sedative, stimulant, and other subjective effects of marijuana: relationships to smoking techniques. Pharmacol Biochem Behav 59:405-12
Block, R I (1996) Does heavy marijuana use impair human cognition and brain function? JAMA 275:560-1
Block, R I; Ghoneim, M M (1993) Effects of chronic marijuana use on human cognition. Psychopharmacology (Berl) 110:219-28
Block, R I; Farinpour, R; Braverman, K (1992) Acute effects of marijuana on cognition: relationships to chronic effects and smoking techniques. Pharmacol Biochem Behav 43:907-17
Block, R I; Farinpour, R; Schlechte, J A (1991) Effects of chronic marijuana use on testosterone, luteinizing hormone, follicle stimulating hormone, prolactin and cortisol in men and women. Drug Alcohol Depend 28:121-8
Block, R I; Farnham, S; Braverman, K et al. (1990) Long-term marijuana use and subsequent effects on learning and cognitive functions related to school achievement: preliminary study. NIDA Res Monogr 101:96-111
Block, R I; Farnham, S; Braverman, K et al. (1989) Norms for free associations and five types of constrained associations. Psychol Rep 64:1065-6