Cannabis Use May Trigger Brain Changes Seen in Schizophrenia

Exposure to delta-9-tetrahydro-cannabinol (THC) in adolescence may cause changes to the brain that resemble features of schizophrenia. Researchers published their findings, which were based on a rodent model, in the journal Cerebral Cortex.

“We report that adolescent, but not adult, THC exposure induces long-term neuropsychiatric-like phenotypes similar to those observed in clinical populations,” the study’s authors wrote.

The investigators used a combination of behavioral and molecular analyses with in vivo neuronal electrophysiology to compare the long-term impact of exposure to THC in adolescent and adult rodents.

Results indicated that adolescents exposed to THC exhibited abnormal behaviors such as social withdrawal, as well as increased anxiety and cognitive disorganization. These behaviors are similar to those seen in the positive and negative symptoms of schizophrenia. The adolescent rodents also had abnormal levels of dopamine—all these changes continued into early adulthood.

In addition, the study’s authors noted that there were substantial changes to several prefrontal cortical molecular pathways, which is consistent with the subcortical DAergic dysregulation that characterizes schizophrenia.

“Our findings demonstrate a profound dissociation in relative risk profiles for adolescent versus adulthood exposure to THC in terms of neuronal, behavioral, and molecular markers resembling neuropsychiatric pathology,” the researchers concluded.

—Lauren LeBano


Renard J, Rosen LG, Loureiro M, et al. Adolescent Cannabinoid Exposure Induces a Persistent Sub-Cortical Hyper-Dopaminergic State and Associated Molecular Adaptations in the Prefrontal Cortex. Cerebral Cortex. 2016 4 Jan;[Epub ahead of print].