Long-Term Effects of Daily High-Dose Cannabis Edible Use
Daily high-dose cannabis edible use carries significant long-term health risks that affect multiple organ systems, with the most concerning being psychiatric complications (including cannabis use disorder in 10% of chronic users), cannabinoid hyperemesis syndrome, cardiovascular events, and cognitive impairment—risks that are well-documented and outweigh uncertain therapeutic benefits. 1
Gastrointestinal Effects
Cannabinoid hyperemesis syndrome is an increasingly recognized consequence of long-standing cannabis use (more than 4 times per week for over a year), and high-dose use specifically precedes its development in most cases. 1 This syndrome presents as:
- Cyclical emetic episodes that mimic cyclic vomiting syndrome 1
- Characteristic relief with hot showers 1
- Treatment requires complete cannabis cessation 1
Psychiatric and Neurological Risks
The psychiatric consequences of chronic high-dose cannabis use represent the most significant threat to quality of life:
Cannabis use disorder develops in approximately 10% of adults with chronic use, characterized by clinically significant impairment including using more cannabis than expected and difficulty cutting back. 1, 2 A randomized trial demonstrated that medical cannabis card recipients had almost twice the incidence (17% versus 9%) of developing cannabis use disorder within just 12 weeks compared to controls. 1
High doses of THC are specifically associated with psychotic symptoms and can precipitate severe anxiety, especially in vulnerable individuals. 2, 3 Cannabis use may increase risk for developing depressive disorders and exacerbate existing psychiatric disorders. 1, 3
Cognitive effects include:
- Impaired verbal learning and memory 3
- Deficits in attention and executive function 3
- Reduced processing speed in long-term users 3
- Disrupted connectivity in the prefrontal cortex affecting decision-making 3
Early onset of cannabis use, especially weekly or daily use, strongly predicts future dependence and neuropsychological decline. 1, 2, 3
Cardiovascular Complications
Cannabis use is associated with adverse cardiovascular events including:
However, there is no evidence that cumulative lifetime use is associated with higher incidence of cardiovascular disease mortality overall. 1
Hepatotoxicity (CBD-Specific)
For CBD-containing products, hepatotoxicity presents a dose-dependent risk:
- Nearly 6-fold increase in liver enzyme elevation has been reported 1
- No cases occurred in adults using total CBD doses below 300 mg/day 1
- Transaminase elevations are typically reversible and occur within the first 2 months 1
- Monitoring liver enzymes is important when using CBD products 1
Respiratory Effects
Conflicting data exist regarding cannabis use and respiratory disease, often confounded by concomitant tobacco use. 1 The association with impaired lung function, asthma, COPD, and pneumonia risks remains unclear. 1 Notably, edible consumption avoids the respiratory risks associated with smoking. 3
Withdrawal Syndrome
Long-term daily cannabis users experience non-life-threatening but distressing withdrawal symptoms after cessation, including:
- Irritability, restlessness, and anxiety 1
- Sleep disturbances 1, 3
- Appetite changes and abdominal pain 1, 3
- Symptoms typically occur within 3 days and may last up to 14 days 1, 3
Cancer Risk
No clear evidence demonstrates that cannabis use increases risk of lung cancer (particularly relevant since edibles avoid inhalation). 1 The association between cannabis use and cancer development remains unclear, except for a possible link with testicular cancer. 1
Functional Impairment
Cannabis users are more than twice as likely to be involved in motor vehicle crashes. 1, 2, 4 This risk is amplified when combined with alcohol. 1
Critical Clinical Considerations
The 2024 ASCO guideline emphasizes that while adults with cancer who ingest excessive cannabis are not at risk for respiratory depression like with opioids, overdoses can be distressing and place individuals at high risk for falls and healthcare utilization. 1
The increasing potency of cannabis products (THC concentrations nearly doubled from 9% in 2008 to 17% in 2017, with concentrates reaching 70%) significantly elevates all documented health risks. 3
Cannabis should be avoided entirely if there is a history of psychotic episodes or breaks with reality. 2