Risks of Regular Marijuana Use on Mood and Sleep in Young Adults
Regular marijuana use in young adults significantly increases the risk of mood disorders, anxiety, depression, and sleep disturbances, with approximately 10% developing cannabis use disorder and experiencing withdrawal symptoms including severe sleep problems when trying to quit. 1, 2
Impact on Mood and Mental Health
Depression and Anxiety Risks
- Cannabis use is directly associated with increased risk for developing depressive disorders and can worsen existing psychiatric conditions in vulnerable individuals. 2
- Adults who use cannabis have a higher risk of behavioral health problems, including both anxiety and depression. 1
- High doses of THC (the main psychoactive component) can precipitate severe anxiety and psychotic symptoms, especially in vulnerable individuals. 1
- Young adults with frequent cannabis use show heightened mood symptoms even when excluding those with pre-existing psychiatric conditions. 3
Brain Development Concerns
- Cannabis causes measurable brain alterations, particularly in young adults, including changes in gray matter volume, cortical thickness, and disrupted connectivity in the prefrontal cortex that affects decision-making and impulse control. 2
- Early onset of cannabis use, especially weekly or daily use, strongly predicts future dependence, neuropsychological decline, elevated risk for psychotic disorders in adulthood, higher risk for depression, and suicidal ideation or behavior. 2
- The developing young adult brain shows increased susceptibility to cannabis-induced structural damage compared to older adults. 2
Impact on Sleep
Paradoxical Sleep Effects
- For young adults without depression or anxiety, using cannabis 20 or more days per month worsens sleep problems over time. 4
- Only young adults with pre-existing depression/anxiety AND pre-existing sleep problems showed modest sleep improvement with frequent cannabis use, but this comes with significant risks. 4
- Cannabis-using young adults report significantly more sleep problems during abstinence periods compared to non-users. 3
Withdrawal-Related Sleep Disruption
- Long-term daily cannabis users experience withdrawal symptoms within 3 days of cessation that last up to 14 days, with sleep disturbances being among the most prominent symptoms. 1, 2
- During monitored abstinence, cannabis-using young adults demonstrate heightened sleep-related withdrawal symptoms that peak during the first week before gradually improving. 3
- Withdrawal symptoms include irritability, restlessness, anxiety, sleep disturbances, changes in appetite, and abdominal pain. 1
Risk of Addiction and Dependence
Cannabis Use Disorder
- Approximately 10% of adults with chronic cannabis use develop cannabis use disorder, characterized by clinically significant impairment or distress. 1, 2
- Early onset of cannabis use, especially weekly or daily use, strongly predicts future dependence. 2, 5
- A randomized trial found that participants who received a medical cannabis card had almost twice the incidence of developing cannabis use disorder within 12 weeks compared to controls. 2
Additional Physical Health Risks
Cardiovascular Effects
- Cannabis is associated with adverse cardiovascular events, including arrhythmias, orthostatic hypotension, myocardial infarction, and stroke. 1, 2
- Cannabis use causes tachycardia with acute use and can trigger myocardial ischemia in at-risk individuals. 2
Respiratory Problems
- Cannabis smoking affects lung function and is associated with chronic bronchitis and chronic obstructive pulmonary disease. 2, 5
Driving Safety
- Cannabis users are more than twice as likely to be involved in motor vehicle accidents because it impairs reaction time and coordination. 1, 5
- The percentage of fatal motor vehicle accidents involving cannabis alone increased from 9.0% in 2000 to 21.5% in 2018. 5
Increasing Potency Concerns
- The average THC concentration in cannabis products has almost doubled from 9% in 2008 to 17% in 2017, with some concentrates reaching 70% THC, significantly elevating all health risks. 2
- Higher doses of THC are associated with more severe acute effects, including psychosis in vulnerable individuals. 2
Critical Pitfalls to Avoid
- Do not use cannabis to self-treat sleep problems if you don't have pre-existing depression or anxiety—it will likely make your sleep worse over time. 4
- Avoid cannabis if there is any personal or family history of psychotic episodes or breaks with reality. 1
- Be aware that cannabis can interfere with anxiety medications and should not be used simultaneously. 1
- Recognize that what may feel like improved sleep initially can lead to dependence and worse sleep problems when trying to quit. 3