Table 1.

Clinical Trials of Cannabidiol in Epilepsy

Study	Treatments (subjects per group)	Duration	Outcome	Toxicity	Limitations
Mechoulam & Carlini, (1978)	TRE – CBD 200 mg/day (4) TRE – Placebo (5)	3 months	CBD: 2 seizure free; 1 partial improvement; 1 no change	None	No baseline seizure frequency, no definition of improvement; unclear if AEDs were changed; small N/limited power; not truly randomized-blinded; unknown if groups were matched
Cunha et al (1980)	TRE-TLE CBD (7) * TRE-TLE Placebo (8)*,**	200–300 mg/day for 3- 18 wks	Last visit: 4 CBD, 1 placebo	Somnolence	Not clearly blinded since one patient transferred groups and doses were adjusted in CBD but no mention of this in placebo group and CBD group received had longer average treatment
Ames et al (1986)	IDD- TRE CBD (?6)$ IDD- TRE Placebo (?6)$ x 4 wks	CBD 300/day x1 wk; 200/dy x 3 wks	No difference between CBD v. Placebo	Somnolence	This was a letter to the editor and details are lacking.
Trembly et al (1990)	TRE (?10 or 12)$$	3 mos baseline; 6 mos placebo: Randomized to either 6 mos placebo v. CBD 100 tid; then crossover for 6 mos on alternative treatment.	no change in seizure frequency or cognitive/behavioral tests	None	Only truly double blind study. Unclear why sample size differed in two reports. Data reported is incomplete

TRE: treatment-resistant epilepsy, TLE: temporal lobe epilepsy, IDD: intellectual/developmental disability

^*Frequent convulsions for > = 1year; – 1 GTCSz per week

^**One patient transferred from placebo to treatment after 1 month

^$12 subjects were divided into two groups, but distribution uncertain

^$$Abstract and subsequent book chapter have different N’s (10 and 12)