A growing number of states have legalized medical marijuana for the treatment of posttraumatic stress disorder (PTSD), and many veterans support this legalization.
In one study, rats were exposed to a traumatic event (in this case, an electric shock) and were then given synthetic cannabinoids (a component of marijuana), sertraline (Zoloft), or no treatment. The rats were then subjected to trauma reminders that were designed to trigger memories of the shock. The rats treated with synthetic cannabinoids showed fewer PTSD symptoms than those given sertraline or no treatment.
No clinical trials investigating the effects of marijuana or its active ingredients on PTSD have yet been completed, but researchers believe current evidence warrants further study.
Pros: Stress-Related Depression
Tetrahydrocannabinol (THC), an active ingredient in marijuana, may help alleviate stress-related depression. THC is similar to endocannabinoids, which are compounds in the brain that affect motor control, cognition, emotions, and behavior. Animals under chronic stress experience decreased production of endocannabinoids, resulting in depressive symptoms.
Because THC is chemically similar to endocannabinoids, scientists hypothesize that it could be used to improve symptoms in people suffering from stress-related depression. Currently, the research is only preliminary, and researchers must ensure the treatment would be safe and effective before starting human trials.
Pros: Alzheimer’s Disease
THC may help lower beta-amyloid levels in Alzheimer’s disease. In a recent study, researchers inserted THC into Alzheimer’s disease cells and measured the levels of beta-amyloid after treatment. Their findings indicated that THC lowered beta-amyloid levels in cells, with higher doses resulting in lower levels. THC also improved mitochondrial function in the cells, generating more energy.
Though the results of this study are promising, further research will be needed to see if THC can be a treatment option for people with Alzheimer’s disease.
A randomized, double-blind clinical trial published in Translational Psychiatry compared the efficacy of treating schizophrenia with cannabidiol versus amisulpride, an antipsychotic medication. The results of the study showed that treatment with cannabidiol and amisulpride both significantly improved symptoms. However, cannabidiol actually showed fewer side effects than amisulpride, such as motor impairments and weight gain, which can influence adherence to treatment.
While the study results are preliminary, the researchers believe that their findings warrant further clinical trials. Neuropsychological and neuroimaging studies may also explore whether cannabidiol can potentially reverse impaired brain functioning in people with schizophrenia.
Pros: Other Medical Uses for Marijuana
In addition to use in individuals with psychiatric disorders, marijuana has a growing number of other medical applications. Medical marijuana is frequently prescribed for pain resulting from conditions including headache, cancer, glaucoma, or nerve pain. It is also commonly used for treating chemotherapy-induced nausea, stimulating appetite in HIV/AIDS patients, and reducing spasms in neuromuscular disorders like multiple sclerosis.
Recently, studies have been exploring the potential of marijuana and its various components for the treatment of pediatric seizures. While some evidence has been promising, more studies are still needed.
Although some studies have shown that marijuana may provide benefit in those with PTSD, others have found evidence that marijuana may worsen symptoms.
An observational study included 2,276 participants admitted to Veterans Affairs treatment programs for PTSD. Participants were evaluated for PTSD severity upon admission and 4 months after discharge, and their use of marijuana was also recorded.
Participants who reported using marijuana had more severe PTSD than those who had never used the drug. Those who stopped using marijuana during treatment showed significantly reduced PTSD symptoms at follow-up compared with baseline. Additionally, those who started using marijuana during treatment were the most likely to exhibit violent behavior and addiction.
Cons: Bipolar Disorder
For people with bipolar disorder, marijuana use can worsen manic or depressive symptoms.
Researchers looked at the emotional state and drug use of people with bipolar disorder who were not currently experiencing a manic or depressive episode. Over a 6-day period, participants self-recorded their feelings and reactions to drug use.
Using marijuana was associated with an increase in positive mood, manic symptoms, and depressive symptoms. Participants who experienced increases in positive mood or manic symptoms were not the same participants who experienced an increase in depressive symptoms, indicating that the drug affects people with bipolar disorder differently.
Other researchers conducted a literature review involving 2,391 participants who had experienced manic symptoms. In people with diagnosed bipolar disorder, using marijuana significantly increased their manic symptoms.
Cons: Effects on the Brain
Chronic marijuana use may shrink the orbitofrontal cortex in the brain. Researchers looked at the brains of 48 individuals who used marijuana an average of three times per day. The participants were found to have smaller-than-average volume in their orbitofrontal cortex. Additionally, brain scans revealed more “wiring” between participants’ brain neurons, which may mean that their brains are compensating for a decrease in gray matter.
Cons: Childhood Behavioral Disorders
A review published in the Journal of Developmental & Behavioral Pediatrics discourages the use of medical marijuana for the treatment of childhood behavioral disorders. Although studies of the effects of medical marijuana on various conditions are on the rise, very few show that the drug is effective in treating childhood behavioral or developmental disorders. In fact, several studies suggest that marijuana can negatively affect the developing brains of children and adolescents.
Regular marijuana users may have a five-fold increased risk of experiencing psychosis. A study looked at 780 participants, including 410 people being treated for psychiatric conditions including schizophrenia and bipolar disorder. The researchers surveyed participants about their marijuana use and monitored each person for episodes of psychosis. Over a 6-year period, people who used marijuana daily — especially those who used high-potency formulations — were five times more likely to experience psychosis than those who never used marijuana.
Marijuana users are at increased risk of experiencing sleep problems, especially if they started using the drug before age 15. A study that included 1,800 adults looked at participants’ marijuana use over the past month, age of initiating drug use, and sleep problems.
Participants who had started using marijuana before age 15 had an increased risk of sleep problems, regardless of their current pattern of marijuana use. Current marijuana users were also more likely to experience sleep problems compared with nonusers, including problems falling asleep, experiencing nonrestorative sleep, and daytime sleepiness.
Cons: Adverse Effects on Teens
Adolescents who start using marijuana regularly before age 17 are at increased risk for a variety of adverse outcomes. A meta-analysis included data on more than 3,700 participants and looked at the relationship between marijuana use and adverse outcomes. Adolescents who used marijuana were more likely to drop out of high school, experience marijuana dependence, use other illegal substances, and attempt suicide compared with nonusers.
Cons: Impaired Memory
Young adults who used marijuana regularly as teenagers may have memory problems and experience changes in brain structure, even after an average of 2 years since using the drug. In one study, participants took a memory test and underwent brain scans. Participants who had used marijuana as teenagers performed significantly worse on the memory tests and had abnormally shaped hippocampi compared with those who did not use marijuana.
While the results of the study show a correlation between marijuana and memory problems, causation cannot be determined from this study alone. If marijuana is the reason for these problems, this study shows that the effects do not fade quickly.
While research has historically linked cannabis use to schizophrenia, no studies have established causation. However, new research is shedding light on the link, which may be due to genetic variants.
A study found that people with a genetic predisposition to schizophrenia were more likely to use marijuana than those without the genetic risk. The study included 2,082 healthy individuals, approximately half of whom reported using marijuana. The researchers looked at the number of schizophrenia-linked genetic variants that each participant carried and then looked at their likelihood of using marijuana.
Results of the study indicated that people with genes related to schizophrenia were more likely to use marijuana (and use it more often) compared with those without these genes. The results suggest that the same genes may be involved in both schizophrenia and marijuana use.
As more states legalize the use of medical marijuana, researchers have conducted studies that explore how marijuana use affects various conditions. Individuals with certain psychiatric disorders seem to benefit from marijuana use, while others may experience adverse effects. Read through the slideshow to see how marijuana may positively or negatively affect different psychiatric illnesses based on existing research.