From the Guidelines
Long-term THC oil use is associated with significant health risks, and I strongly recommend limiting or avoiding its use, especially for individuals concerned about mental health, cognitive function, or respiratory health. The potential risks of long-term THC oil use include cannabis use disorder, impaired memory and executive function, and increased risk of anxiety, depression, and psychosis in vulnerable individuals 1. Regular THC use may lead to tolerance, withdrawal, and continued use despite negative consequences, with approximately 9% of users developing cannabis use disorder. Additionally, THC can worsen mental health conditions, and its use has been linked to adverse cardiovascular events, including myocardial infarction and stroke 1. If using THC oil for medical purposes, it is essential to work with a healthcare provider to establish the minimum effective dose and regularly evaluate benefits versus risks. For pain management, consider starting with 2.5-5mg THC, gradually increasing if needed, while monitoring for side effects. Alternative options like CBD products, physical therapy, or other pain management strategies may provide relief with fewer risks. The body develops tolerance to THC over time, potentially leading to dependence, and abrupt discontinuation can cause withdrawal symptoms, including irritability, sleep disturbances, and decreased appetite 1. Key considerations for long-term THC oil use include:
- Mental health risks, such as anxiety, depression, and psychosis
- Cognitive impairment, including memory and executive function
- Respiratory health risks, including chronic bronchitis and chronic obstructive pulmonary disease
- Cardiovascular risks, including myocardial infarction and stroke
- Risk of cannabis use disorder and dependence
- Potential for withdrawal symptoms with abrupt discontinuation. Given the potential risks, it is crucial to approach long-term THC oil use with caution and carefully weigh the benefits against the risks.
From the Research
Long-term THC Oil Use
- Long-term use of THC oil can result in respiratory and cardiovascular toxicity, and has been associated with a range of psychiatric conditions 2.
- Cannabinoid hyperemesis syndrome can occur with chronic use of THC oil 2.
- THC oil can impair memory in the short run, which becomes more significant with chronic use, and may also be accompanied by poorer effort, slower processing, and impacted attention 3.
- Long-term use of THC oil, especially at an earlier age, is a risk factor for neurocognitive deficits, with neuroimaging studies showing reduced hippocampal volume and density 3.
Mental Health Effects
- High doses of CBD, often combined with THC in THC oil, can provide some acute relief in anxiety 4, 5.
- CBD + THC combinations in THC oil can alleviate withdrawal in cannabis use disorder and improve sleep 5.
- However, THC in THC oil is associated with dose-dependent adverse events and, in some cases, deterioration of primary study outcomes, such as in psychosis 5.
- Risks of bias across studies on THC oil use are prevalent, and no study has found long-lasting medicinal effects or improvement 5.
Safety and Tolerability
- THC/CBD combination medicines, including THC oil, have a good tolerability and safety profile relative to opioid analgesics, but should be avoided in patients predisposed to depression, psychosis, and suicide 6.
- Non-serious adverse events from THC oil use are usually dose-proportional, subject to tachyphylaxis, and are rarely dose-limiting when patients are commenced on a low dose with gradual up-titration 6.
- THC and CBD in THC oil inhibit several Phase I and II metabolism enzymes, which increases the exposure to a wide range of drugs, and appropriate care needs to be taken 6.