Health Risks of Daily Marijuana Use
Daily marijuana use is associated with significant cardiovascular risks including increased stroke risk, myocardial infarction, tachycardia, and orthostatic hypotension, as well as risks of cannabis dependence, respiratory disease, cognitive impairment, and mental health disorders. 1
Cardiovascular Risks
Daily cannabis use poses several cardiovascular concerns:
- Dose-dependent stroke risk: More frequent than once-weekly cannabis use is associated with elevated stroke/TIA risk 1
- Acute cardiovascular effects include:
- Tachycardia (increased heart rate)
- Blood pressure changes
- Orthostatic hypotension, particularly with heavy acute and chronic use 1
- Increased myocardial ischemia risk in vulnerable individuals 1
Respiratory System Effects
- Impaired respiratory function is a significant concern with smoked cannabis 2
- Respiratory diseases are among the most probable adverse effects of regular cannabis use 2
- Vaping cannabis presents unique risks including acute lung injury 1
Mental Health Impacts
Daily cannabis use is associated with several mental health concerns:
- Cannabis dependence syndrome (substance use disorder) can develop, particularly with:
- High-dose, long-term use
- Initiation during adolescence 3
- Specific withdrawal symptoms can occur with cessation 3
- Psychosis risk: Cannabis use can worsen positive psychotic symptoms (5.21 times higher risk) and total psychiatric symptoms (7.49 times higher risk) 4
- Other mental health concerns include:
- Anxiety disorders
- Affective disorders
- Cognitive impairment 3
Acute Adverse Effects
Single-use episodes can cause:
- Panic attacks and anxiety
- Psychotic symptoms
- Impaired attention and concentration
- Motor incoordination
- Nausea (including hyperemesis syndrome) 5
- Increased risk of motor vehicle crashes, especially fatal collisions 5, 4
Risk Factors That Increase Harm
Several factors can amplify the risks of daily cannabis use:
- Increasing THC potency: Average THC concentration has risen from 9% (2008) to 17% (2017), with concentrates reaching up to 70% THC 1
- Declining CBD content: Modern cannabis often has undetectable levels of cannabidiol, which may have protective effects 3
- Method of consumption: Different risks associated with smoking, vaping, or edibles 1
- Age of initiation: Adolescent use carries higher risks for developmental impacts 3
- Edibles can cause more intense and prolonged effects due to delayed absorption 1
High-Risk Populations
- Adolescents and young adults (18-25 years) are particularly vulnerable to developmental impacts 1
- Adults over 65 years may experience more pronounced cardiovascular effects 1
- Pregnant women: Convincing evidence shows increased risk of small for gestational age (1.61 times higher) and low birth weight (1.43 times higher) 4
- Individuals with cardiovascular risk factors 1
- People prone to or with existing mental health disorders 4
- Drivers: 1.27 times higher risk of car crashes 4
Clinical Implications
- Screen for cannabis use patterns in patients with cardiovascular risk factors 1
- Screen for cannabis use disorder, particularly in patients using cannabis for sleep (as it can alter normal sleep cycles) 1
- Advise against combining THC with sedative medications or other substances that affect heart rate or blood pressure 1
- Treatment options for cannabis dependence include:
- Motivational encouragement
- Cognitive behavioral therapy
- Contingency management
- Family therapy (for adolescents) 3
Common Pitfalls and Caveats
- Underestimating potency: Modern cannabis products have significantly higher THC concentrations than in previous decades 1
- Assuming medical safety: Even medicinal cannabis carries risks of adverse events related to the central nervous system, psychological effects, and vision 4
- Overlooking cardiovascular risks: Cannabis-induced cardiovascular effects may be particularly dangerous in those with pre-existing conditions 1
- Dismissing dependence potential: Cannabis dependence is a real clinical entity requiring specific treatment approaches 3, 2