Preteen marijuana use boosts risk for depression, PTSD.
Among the cohort of 14- to 18-year-olds, 57 (42%) began smoking marijuana before age 13 and 79 (58%) started marijuana use during their teenage years. Those whose marijuana use started before age 13 were more likely to have comorbid posttraumatic stress disorder (PTSD)--9 patients (16%) vs. 5 patients (6%)--and to have a history of suicide attempts--18 patients(32%) vs. 15 patients (19%)--at the time they entered treatment for substance dependence.
Preteen initiation of marijuana use also was associated with a history of past traffic violations, in four patients (7%) compared with one patient (1%), Dr. Youssef Mahfoud and his associates reported at the annual conference of the American Society of Addiction Medicine.
Marijuana dependence was significantly more likely in preteen users than in later users--54 patients (95%) vs. 61 (77%). Hallucinogen dependence also was more common in those who started marijuana as preteens: 25 patients (44%) vs. 21 patients (27%), said Dr. Mahfoud, a fellow in the psychiatry department of Case Western Reserve University, Cleveland.
In general, those young people who began using marijuana as preteens were more likely to be dependent on more than one substance.
The preteen marijuana users smoked more cigarettes per day (11 per patient) compared with the teen marijuana group (8 per patient) and were younger when they entered treatment (15.9 years vs. 16.5 years).
The associations between preteen marijuana use and more problems at the time youths enter treatment are not necessarily causal, Dr. Mahfoud noted. Preteens with PTSD, for example, might be using marijuana to self-medicate.
The increased rate of suicide attempts in preteen marijuana users might be attributable to a potentially increased rate of comorbid depression, but the study did not assess depression rates, he added.
"Marijuana, the most commonly used illicit substance in the United States, is perceived by many youths to be harmless," but it might pose special risks for preteen users, whose adolescent brain growth peaks around age 12, he said.
Previous studies have shown that marijuana use commonly is associated with increased rates of anxiety, legal problems, dropping out of school, and cognitive impairment with long-term use, he noted.
Dr. Mahfoud and his associates retrospectively studied data from semistructured interviews of patients, medical charts, and reports by the youths, parents, and clinicians. Because these were treatment-seeking patients, the findings might not be representative of other populations.
The cohort was 66% white. Preteen marijuana use was more common among Hispanics (8 patients, or 14%) than among non-Hispanics (2 patients, or 3%) and among patients with less-educated parents.
Overall, 57% of patients had a parent with a substance dependence disorder, and 57% came from single-parent households.
The study is the largest of substance-dependent young people that contained a generally gender-balanced cohort--47% male, 53% female, Dr. Mahfoud said.
Future research should investigate the way in which preteen marijuana might interfere with the brain's major growth spurt at age 12, Dr. Mahfoud suggested.
Major Finding: Starting marijuana use in the preteen years instead of the teen years was associated with a significantly greater likelihood of current posttraumatic stress disorder (16% vs. 6%) and a history of suicide attempts (32% vs. 19%).
Data Source: Retrospective study of 139 teenagers in residential treatment for substance dependence disorder.
Disclosures: Dr. Mahfoud said the investigators have no pertinent conflicts of interest. The study was funded by the National Institute on Alcohol Abuse and Alcoholism and the John Templeton Foundation.
FROM THE ANNUAL CONFERENCE OF THE AMERICAN SOCIETY OF ADDICTION MEDICINE
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|Title Annotation:||CHILD PSYCHIATRY|
|Publication:||Clinical Psychiatry News|
|Date:||Jul 1, 2010|
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