Table 1.

Incidence and severity of adverse events at least possibly related to placebo, THC, or cannabis plant-extract treatment

TreatmentAdverse event (frequency)MildModerateSevere
THC = Δ9-Tetrahydrocannabinol.
PlaceboTotal (20)1460
    Somnolence (4)31
    Increased spasticity (3)12
    Dizziness (3)3
    Headache (3)3
    Others (7)43
THCTotal (20)1820
    Dry mouth (5)5
    Headache (4)4
    Others (11)92
Plant extractTotal (41)3281
    Dizziness (6)6
    Increased spasticity (5)23
    Somnolence (5)5
    Headache (5)41
    Ataxia (3)3
    Dry mouth (3)3
    Emotional lability (3)21
    Others (11)731