From the Guidelines
Yes, there is evidence that THC can have harmful side effects, including anxiety, memory impairment, elevated heart rate and blood pressure, and potential long-term consequences such as mental health problems, chronic respiratory issues, and adverse cardiovascular events. The average THC concentration in cannabis plants has increased dramatically over the past few decades, potentially elevating the risk for health problems, as noted in a 2024 position paper from the American College of Physicians 1. Some evidence indicates that high doses of THC may be associated with psychosis, and cannabis use may have a deleterious effect on adolescent brain development and well-being, with potential links to major depression and suicidal ideation 1.
Key points to consider include:
- Mental health and chronic respiratory problems are among possible health effects in people who use cannabis over the long term 1
- Smoking cannabis may affect lung function and is associated with pulmonary conditions like chronic bronchitis and chronic obstructive pulmonary disease 1
- Cannabis smoking may be associated with adverse cardiovascular events, including myocardial infarction and stroke 1
- Components of vaporized cannabis may pose unique risks, such as acute lung injury after using electronic cigarettes containing THC concentrate and vitamin E acetate 1
The potency of modern cannabis products, with some concentrates containing up to 70% THC, potentially increases these risks, and individual responses to THC vary based on factors like genetics, previous experience with cannabis, and concurrent use of other substances. As such, it is crucial to approach THC use with caution, considering the potential for harmful side effects, particularly in vulnerable populations such as adolescents and young adults.
From the Research
Harmful Side Effects of THC
- Acute consumption of high THC doses can cause time-limited mental, gastrointestinal, and cardiovascular problems and motor vehicle accidents 2
- Chronic patterns of cannabis use have been associated with multiple adverse outcomes, such as disrupted learning, impaired cognitive performance, reduced educational attainment, and an increased risk of cannabis use disorder, psychosis/schizophrenia, mood and anxiety disorders, and suicidal behaviors 2
- Physical health risks, including respiratory and cardiovascular problems, prematurity, and restricted fetal growth, have also been linked with repeated consumption of cannabis with a high THC content 2
- Adverse effects from higher doses of THC can include fear, distrust, and a profound state of unease, hallucinations, ataxia, stupor, and seizures 3
- Long-term use of THC can result in respiratory and cardiovascular toxicity and has been associated with a range of psychiatric conditions, including cannabinoid hyperemesis syndrome 3
Mental Health Risks
- High doses of THC have been associated with dose-dependent adverse events and, in some cases, deterioration of primary study outcomes, such as in psychosis 4
- THC use has been linked to an increased risk of anxiety disorders, tic disorders, autism spectrum disorder, attention-deficit hyperactivity disorder, obsessive-compulsive disorders, anorexia nervosa, schizophrenia, psychosis, substance use disorders, insomnia, and bipolar disorders 4
- Cannabis use disorder is the most common illicit substance use disorder, and individuals with CUD have high rates of comorbid anxiety disorders 5
Addiction and Withdrawal
- Regular use of high THC products can produce addiction, or cannabis use disorder (CUD) 2
- The adverse effects of withdrawal from THC can lead to regular use and have adverse implications for public safety and health expenditure 6
- Cannabis is highly addictive, and children are more susceptible to cannabis toxicity, particularly seizures and coma 3