Marijuana Studies

Is marijuana safe for children and adolescents?

With less perceived risk comes increased use, but is it safe?
Authored by: Amir Levine, MD, Division of Child and Adolescent Psychiatry, Department of Psychiarty, Columbia University

Evidence for the Risks and Consequences of Adolescent Cannabis Exposure

The majority of the clinical and preclinical data point to a strong correlation between adolescent cannabinoid exposure and persistent, adverse neuropsychiatric outcomes in adulthood. Based on the data in the current literature, a strong association is found between early, frequent, and heavy adolescent cannabis exposure and poor cognitive and psychiatric outcomes in adulthood, yet definite conclusions cannot yet be made as to whether cannabis use alone has a negative impact on the human adolescent brain.

Authored by: Amir Levine, M.D., Kelly Clemenza, B.A., Moira Rynn, M.D., Jeffrey Lieberman, M.D.

Pre-clinical evidence of the risks and consequences of cannabis exposure to youth

There is compelling evidence, based on data in the current literature, which suggests that cannabis may adversely affect the developing brain. Future research will require carefully designed pre-clinical studies that can assess molecular, structural, and behavioral outcomes, as well as prospective studies in humans, in order to elucidate the full range of potential consequences of adolescent cannabinoid exposure on development and into adulthood.
Authored by: Amir Levine, M.D., Kelly Clemenza, B.A., Moira Rynn, M.D., Jeffrey Lieberman, M.D.

Marijuana may not be harmful to adults … but what about youth?

One of the main reasons for this wave of decriminalization is cumulative scientific evidence and public opinion supporting the belief that marijuana is less harmful than tobacco or alcohol. But there is one enormous and unnoticed caveat to the commonly held view of the relative safety of cannabis. It only applies to adults.
Authored by: Lexie Potamkin, Brigit Rok, Jeffrey Lieberman

Marijuana use: detrimental to youth

Although increasing legalization of marijuana has contributed to the growing belief that marijuana is harmless, research documents the risks of its use by youth are grave. Marijuana is addicting, has adverse effects upon the adolescent brain, is a risk for both cardio-respiratory disease and testicular cancer, and is associated with both psychiatric illness and negative social outcomes. Evidence indicates limited legalization of marijuana has already raised rates of unintended marijuana exposure among young children, and may increase adolescent use.
American College of Pediatricians – April 2016

Marijuana use disorder on the rise, but few receive treatment

There is compelling evidence, based on data in the current literature, which suggests that cannabis may adversely affect the developing brain. Future research will require carefully designed pre-clinical studies that can assess molecular, structural, and behavioral outcomes, as well as prospective studies in humans, in order to elucidate the full range of potential consequences of adolescent cannabinoid exposure on development and into adulthood.
Authored by: Deborah S. Hasin, PhD; Tulshi D. Saha, PhD; Bradley T. Kerridge, PhD; Risë B. Goldstein, PhD,MPH; S.Patricia Chou, PhD; Haitao Zhang, PhD; Jeesun Jung, PhD; Roger P. Pickering, MS; W. June Ruan, MA; Sharon M. Smith, PhD; Boji Huang, MD, PhD; Bridget F. Grant, PhD.

Concurrent and sustained cumulative effects of adolescent marijuana use on subclinical psychotic symptoms

Adolescents who regularly use marijuana may be at heightened risk of developing subclinical and clinical psychotic symptoms. However, this association could be explained by reverse causation or other factors. To address these limitations, the current study examined whether adolescents who engage in regular marijuana use exhibit a systematic increase in subclinical psychotic symptoms that persists during periods of sustained abstinence.
Authored by: Jordan Bechtold, Ph.D., Alison Hipwell, Ph.D., David A. Lewis, M.D., Rolf Loeber, Ph.D., Dustin Pardini, Ph.D.

Notes from the field: death following ingestion of an edible marijuana product — Colorado, March 2014

In March 2014, the Colorado Department of Public Health and Environment (CDPHE) learned of the death of a man aged 19 years after consuming an edible marijuana product. CDPHE reviewed autopsy and police reports to assess factors associated with his death and to guide prevention efforts. The decedent’s friend, aged 23 years, had purchased marijuana cookies and provided one to the decedent. A police report indicated that initially the decedent ate only a single piece of his cookie, as directed by the sales clerk. Approximately 30–60 minutes later, not feeling any effects, he consumed the remainder of the cookie. During the next 2 hours, he reportedly exhibited erratic speech and hostile behaviors. Approximately 3.5 hours after initial ingestion, and 2.5 hours after consuming the remainder of the cookie, he jumped off a fourth floor balcony and died from trauma.

Authored by: Jessica B. Hancock-Allen, MSN; Lisa Barker; Michael VanDyke, PhD2; Dawn B. Holmes, MD

Prevalence of marijuana use disorders in the United States between 2001-2002 and 2012-2013

6 million Americans experienced marijuana use disorder in the past year alone. A new study published in the American Journal of Psychiatry has found that number of Americans who reported using marijuana over a one-year period more than doubled between 2002 and 2013, with nearly as large an increase in marijuana use disorders during that time period. The study also revealed that 2.5 percent of adults—nearly 6 million people—experienced marijuana use disorder in the past year, while 6.3 percent met the diagnostic criteria for the disorder at some point in their lives.
Authored by: Scientists at Columbia University’s Mailman School of Public Health, Columbia University Medical Center, and the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health.

Large longitudinal study documents marijuana-associated cognitive decline from early use

Investigators reported that teens who began smoking marijuana before age 18 and continued with the habit into adulthood lost an average of eight points on IQ tests between the ages of 13 and 38. The early, persistent marijuana users also showed deficits in learning, memory and executive functioning, and even those who eventually quit smoking pot as adults did not regain their full intellectual functioning.Could smoking marijuana as a teen lead to a lower IQ as an adult? The answer is yes, according to a decades-long study that tracked more than 1,000 New Zealanders from adolescence into their late 30s. The study found that those who began smoking marijuana before age 18 and continued with the habit into adulthood lost an average of eight points on IQ tests between the ages of 13 and 38. The early, persistent marijuana users also showed deficits in learning, memory, and executive functioning, and even those who eventually quit smoking pot as adults did not regain their full intellectual functioning.
Authored by: Susan Fitzgerald. This latest research is based on data collected as part of the Dunedin Multidisciplinary Health and Development Study, a prospective study of the health and behavior of 1,037 individuals of varying socioeconomic status born in 1972–1973 in Dunedin, New Zealand