What are the long-term effects of chronic cannabis smoking on anxiety and mood?

Long-Term Effects of Chronic Cannabis Smoking on Anxiety and Mood

Chronic cannabis use carries significant long-term psychiatric risks, including an increased risk for developing depressive disorders and exacerbation of existing psychiatric conditions in vulnerable individuals. 1

Psychiatric Effects

Anxiety Effects

• Cannabis has complex, biphasic effects on anxiety:
  • Short-term: May temporarily reduce anxiety in some users
  • Long-term: Chronic use is associated with worsening of anxiety symptoms 1, 2
  • THC (delta-9-tetrahydrocannabinol) is primarily associated with anxiogenic (anxiety-producing) effects, especially at higher doses 2
  • CBD (cannabidiol) has demonstrated anxiolytic properties in both animal and human studies 2

Mood Effects

• Chronic cannabis use is associated with:
  • Increased risk of developing depressive disorders 1
  • Poorer clinical course in bipolar disorder 3
  • Potential exacerbation of mood disorders in vulnerable individuals 1
  • Disruption of sleep architecture, which can further impact mood regulation 4

Risk Factors and Vulnerability

Age of Onset

• Early onset of cannabis use, especially weekly or daily use, strongly predicts:
  • Future dependence 1
  • Greater psychiatric risk 1
  • More pronounced neurodevelopmental effects in adolescents and young adults 4

Dose-Dependent Effects

• Higher doses and more frequent use correlate with:
  • Greater risk of adverse psychiatric outcomes 1
  • Increased likelihood of developing cannabis use disorder (10% of chronic users) 1
  • More severe withdrawal symptoms upon cessation 1

Individual Temperament Factors

• Harm avoidance traits show reduced association with anxiety and depression among cannabis users 5
• Novelty seeking traits are associated with increased anxiety and depression symptoms, but only among heavy cannabis users 5

Withdrawal and Dependence

Cannabis Use Disorder

• Affects approximately 10% of chronic cannabis users 1
• Characterized by:
  • Using more cannabis than intended
  • Difficulty cutting back on use
  • Clinically significant impairment or distress 1
  • Increased risk in those with medical cannabis cards (17% vs 9% in controls) 1

Withdrawal Symptoms

• Non-life-threatening but clinically significant symptoms include:
  • Irritability and restlessness
  • Anxiety
  • Sleep disturbances
  • Appetite changes
  • Abdominal pain 1
• Typically occur within 3 days after cessation
• May last up to 14 days 1

Clinical Implications

Assessment Considerations

• Screen for cannabis use patterns and frequency
• Evaluate pre-existing mental health conditions that may be exacerbated
• Consider individual risk factors (age, temperament, psychiatric history)
• Monitor for signs of cannabis use disorder or dependence 1, 4

Treatment Approaches

• For patients using cannabis for anxiety or mood symptoms:
  • Discuss evidence-based alternatives with stronger efficacy
  • Consider cognitive behavioral therapy for underlying conditions 4
  • Monitor for withdrawal symptoms if discontinuing use 4
• For those with cannabis-related mood or anxiety disorders:
  • Address both the substance use and psychiatric symptoms
  • Consider that cessation may temporarily worsen anxiety symptoms before improvement 1

Common Pitfalls and Caveats

• Assuming uniform effects across all users (effects vary based on individual factors)
• Failing to distinguish between THC and CBD effects (they have opposing actions on anxiety)
• Overlooking the biphasic nature of cannabis effects (low doses may reduce anxiety while high doses often increase it) 2
• Ignoring potential drug interactions with medications affecting mood or anxiety 4
• Failing to consider the impact of cannabis on sleep architecture, which can secondarily affect mood and anxiety 4