Adolescent substance abuse: the effects of alcohol and marijuana on neuropsychological performance.
BACKGROUND
Adolescence is a period in which cognition and brain undergo dramatic parallel development. Whereas chronic use of alcohol and marijuana is known to cause cognitive impairments in adults, far less is known about the effect of these substances of abuse on adolescent cognition, including possible interactions with developmental processes.


METHODS
Neuropsychological performance, alcohol use, and marijuana use were assessed in 48 adolescents (ages 12 to 18), recruited in 3 groups: a healthy control group (HC, n = 15), a group diagnosed with substance abuse or dependence (SUD, n = 19), and a group with a family history positive for alcohol use disorder (AUD) but no personal substance use disorder (FHP, n = 14). Age, drinks per drinking day (DPDD), percentage days drinking, and percentage days using marijuana were considered as covariates in a MANCOVA in which 6 neuropsychological composites (Verbal Reasoning, Visuospatial Ability, Executive Function, Memory, Attention, and Processing Speed) served as dependent variables.


RESULTS
More DPDD predicted poorer performance on Attention and Executive Function composites, and more frequent use of marijuana was associated with poorer Memory performance. In separate analyses, adolescents in the SUD group had lower scores on Attention, Memory, and Processing Speed composites, and FHP adolescents had poorer Visuospatial Ability.


CONCLUSIONS
In combination, these analyses suggest that heavy alcohol use in adolescence leads to reduction in attention and executive functioning and that marijuana use exerts an independent deleterious effect on memory. At the same time, premorbid deficits associated with family history of AUD appeared to be specific to visuospatial ability.
Department of Psychiatry, University of New Mexico, Albuquerque, 87131, USA. rjthoma@salud.unm.edu
Robert J
RJ
Thoma
Mollie A
MA
Monnig
Per A
PA
Lysne
David A
DA
Ruhl
Jessica A
JA
Pommy
Michael
M
Bogenschutz
J Scott
JS
Tonigan
Ronald A
RA
Yeo
D000293:Adolescent; D019973:Alcohol-Related Disorders / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D000437:Alcoholism / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D001288:Attention; D001921:Brain / Q000503:physiopathology; D002648:Child; D003071:Cognition; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D008568:Memory; D008606:Mental Processes; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D013028:Space Perception