What are the recommendations for marijuana use in a healthy adult with no significant medical history?

Marijuana Use in Healthy Adults: Clinical Recommendations

For healthy adults with no significant medical history, marijuana use is not recommended due to well-established risks including motor vehicle accidents, cognitive impairment, and potential for cannabis use disorder, with no evidence-based medical benefit in this population. 1

Key Safety Concerns for Healthy Adults

Motor Vehicle Safety

• Cannabis users are more than twice as likely to be involved in motor vehicle crashes compared to non-users. 1
• Fatal motor vehicle accidents involving cannabis increased from 9.0% in 2000 to 21.5% in 2018 for cannabis alone. 1
• Avoid driving for up to 12 hours after cannabis consumption, depending on the product type. 1
• Higher blood levels of cannabis significantly increase the risk of fatal accidents, especially when combined with alcohol. 1

Cognitive and Neurological Effects

• Cannabis impairs executive function, memory, and attention, with effects becoming more significant with chronic use. 2
• Adolescent and young adult users face particular risks including disrupted learning, impaired cognitive performance, and reduced educational attainment. 3
• Neuroimaging studies demonstrate reduced hippocampal volume and density with long-term use. 2
• Earlier age of initiation carries higher risk for long-term neurocognitive deficits. 3, 2

Addiction Risk

• Up to 10% of cannabis users meet criteria for lifetime cannabis dependence (cannabis use disorder). 2, 4
• Regular use of high THC products increases the risk of developing cannabis use disorder. 3
• Withdrawal symptoms include irritability, insomnia, and headaches, lasting up to 14 days after cessation. 1

Mental Health Risks

• Cannabis use is associated with convincing evidence of increased risk for psychosis (1.71-fold increase). 5
• In the general population, cannabis worsens positive psychotic symptoms (5.21-fold increase) and total psychiatric symptoms (7.49-fold increase). 5
• Increased risk for mood and anxiety disorders, suicidal behaviors, and depression. 3, 5
• Individuals with personal or family history of psychosis should not use THC-containing products. 6

Cardiovascular Concerns

• THC affects heart rate and blood pressure. 7
• THC-containing products should not be used by individuals with angina or history of myocardial infarction. 6

Common Adverse Effects

Dose-Dependent Effects

• Somnolence, fatigue, dizziness, confusion, nausea, dry mouth, and hypotension are common. 7, 4
• Acute consumption of high THC doses can cause time-limited mental, gastrointestinal, and cardiovascular problems. 3
• Edible cannabis products pose higher risk of emergency department visits due to delayed onset leading to unintentional overdosing. 7

Special Population Risks

• Pregnant individuals should avoid all cannabis use due to convincing evidence of small for gestational age (1.61-fold increase) and low birth weight (1.43-fold increase). 5
• Elderly patients face higher risk of adverse effects due to reduced drug clearance. 7

Drug Interactions

• THC inhibits cytochrome P450 enzymes (CYP3A4, CYP2C9, CYP2C19), affecting metabolism of concurrent medications. 7
• Central nervous system effects may be additive with other medications causing dizziness, confusion, and fatigue. 7
• High-fat meals significantly increase cannabinoid absorption, potentially exacerbating interactions. 7

Legal Considerations

• Cannabis remains a Schedule I controlled substance federally, despite state-level legalization in many jurisdictions. 1, 7
• Variable THC and CBD content in products makes standardization difficult and interactions unpredictable. 7

Clinical Approach for Healthcare Providers

Screening and Communication

• Clinicians should routinely and nonjudgmentally inquire about cannabis use or consideration of use. 1, 7
• For individuals consuming cannabis more than once daily, screening for cannabis use disorder is appropriate. 7
• Assessment should include daily intake, duration of use, and method of consumption. 7

Patient Education

• Health systems should provide unbiased, evidence-based cannabis educational resources to facilitate informed decision-making. 1, 7
• Educate on the difference between THC-dominant (CBD:THC ratio <10:1) and CBD-dominant products (ratio >10:1). 7
• Discuss storage safety to prevent accidental exposures to children and pets. 1

When Medical Use Might Be Considered

While not applicable to healthy adults, clinicians should be aware that cannabis-based medicines have evidence for specific medical conditions including refractory chemotherapy-induced nausea/vomiting, chronic pain, multiple sclerosis spasticity, and certain epilepsy syndromes. 1, 5 However, these indications do not apply to healthy individuals without medical conditions. 1