Cannabis Compound May Restore Learning and Memory in People With Schizophrenia

A new study shows that cannabidiol, known as CBD, improves mental functioning in rats impaired by a condition analogous to schizophrenia in humans.

By Greg Walters 

A chemical compound found in cannabis may improve working memory and recognition in people suffering from schizophrenia, according to a new study that adds a fresh twist to the complex relationship between marijuana and mental health. 

 

The findings by a team of Australian researchers are the latest addition to a growing body of research indicating that the compound, known as cannabidiol, or CBD, improves cognitive functioning in a host of conditions from Alzheimer’s to meningitis, cerebral malaria and stroke — and can reduce the number of seizures in patients with epilepsy. 

Yet the study represents a new strand in the rich tapestry linking cannabis with psychosis, which researchers have been studying for decades. Recreational marijuana use has been shown to aggravate the symptoms of schizophrenia, and even induce psychosis. 

The implication, according to researchers, is that the hundreds of distinct compounds found in cannabis behave in very different ways inside the human brain. 

“We’re not about to say, ‘Go out and smoke pot, it’s good for you,’” said Katrina Green of the University of Wollongong, Australia, who led the study. “There are over 400 chemicals in the cannabis plant. Being able to unravel the potential of each of them is really exciting.”

To illustrate her point, Green draws a metaphor between the dual roles of heroin and morphine, both of which are derived from the same plant. Yet morphine is broadly accepted as having medical value when carefully administered, while heroin is considered to be solely an abusive drug. 

The new research focused squarely on CBD, a non-psychoactive ingredient in marijuana that won’t get you high. Indeed, CBD has actually been shown to reduce the impairment caused by the key psychoactive compound in marijuana, THC. 

Along with hallucinations and delusions, those suffering from schizophrenia — a condition that affects 1 percent of the global population — often also exhibit a deterioration of cognitive abilities like attention, memory, and executive function. 

In the Australian study, rats were induced to have a rodent model of schizophrenia, which is a technique often used to study the disease. They were then treated with CBD. 

Tests showed that CBD “significantly improved” both recognition and working memory in the affected rats. What’s more, rodents given CBD didn’t gain weight, a common side effect of existing medications. Control rats with no illness did not experience negative side effects from taking CBD. 

Cannabidiol also appeared to ameliorate the so-called “negative symptoms” associated with schizophrenia: social withdrawal, flat-lined emotional expression, and lack of enthusiasm or motivation. Administering CBD appeared to improve the rodents’ inclination towards social interaction. 

Strikingly, the potential for CBD to bolster cognition in the face of mental illness isn’t limited to schizophrenia — far from it.

The new study follows on the heels of an extensive review authored by Green, her colleague Nadia Solowij, and their Ph.D student Ashleigh Osborne of existing literature on how CBD impacts cognitive functioning across a range of illnesses.

In short: The compound was found to have widespread effectiveness. 

The review looked carefully at 27 existing research articles in peer-reviewed journals that had reported an effect of CBD on cognition, including studies on stroke, meningitis, sepsis, Alzheimer’s disease, and even deficits caused by exposure to recreational marijuana. 

“The evidence told us that CBD consistently improved cognition — irrespective of the reason behind the cognitive deficit,” said Osborne. “The evidence also showed that CBD would only work in a disease state, having no apparent effect on the healthy brain.” 

The chemical has also been shown to be highly effective as a treatment for epilepsy. 

Earlier this year, a study found that medicine based on cannabidiol cut the number of seizures by half among some patients suffering from a severe form of epilepsy known as Lennox-Gastaut Syndrome.

Yet across the globe, research into CBD has been hampered by the fact that in many places it remains a banned substance. 

In America, CBD is still considered illegal by the federal Drug Enforcement Administration, despite being available over-the-counter in states that have legalized its medicinal use.