Chronic pain: heavy medical cannabis use tied to worsened pain

Takeaway

• Heavy use of medical marijuana in patients with chronic pain was associated with greater pain severity than light use.

Why this matters

• The findings point to the need for cannabis use guidelines designed to promote harm reduction.

Study design

• Study identified 989 daily users of cannabis (medical use only, n=531; medical+recreational use, n=458) for chronic pain.
• Funding: None.

Key results

• Subgroups based on cannabis use/day:
  • light (1-2/day; n=307),
  • moderate (3-4/day; n=382), and
  • heavy (≥5/day; n=300).
• Lower pain severity was noted among light vs moderate and heavy cannabis users (P=.044).
• Lower pain interference (P=.024), positive affect (P=.039), and negative affect (P=.008) were noted in light vs heavy users.
• Low tetrahydrocannabinol and high cannabidiol products were preferred by 44.7% of light users vs 29.0% of moderate users and 12.4% of heavy users.
• Among medical-only participants, light cannabis users (vs moderate and heavy users, respectively; P<.0001) reported lower:
  • pain severity (5.4 vs 6.2 and 6.2) and
  • pain interference (4.4 vs 5.4 and 5.5).
• Compared with heavy cannabis users, light users reported lower positive affect (23.5 vs 25.2; P=.037) and lower negative affect (24.7 vs 26.8; P=.011).

Limitations

• Cross-sectional study.

Coauthored with Chitra Ravi, MPharm