On 2016 Jan 09, David Keller commented:

Without a placebo control group, double-blinding or randomization, the results are difficult to interpret

Without a randomized, double-blinded, placebo-controlled trial, it is not possible to determine how much of the decrease in motor seizures was due to cannabidiol, nor how cannabidiol affected the frequency of serious adverse events, such as status epilepticus and "convulsions". Cannabidiol is a component of cannabis, the persistent use of which has been shown to be associated with neuropsychological decline in childhood through midlife [1].

Reference:

1: Meier MH, et al. Persistent cannabis users show neuropsychological decline from childhood to midlife. Proc Natl Acad Sci U S A. 2012 Oct 2;109(40):E2657-64. PubMed PMID: 22927402

On 2016 Jan 09, David Keller commented:

Without a placebo control group, double-blinding or randomization, the results are difficult to interpret

Without a randomized, double-blinded, placebo-controlled trial, it is not possible to determine how much of the decrease in motor seizures was due to cannabidiol, nor how cannabidiol affected the frequency of serious adverse events, such as status epilepticus and "convulsions". Cannabidiol is a component of cannabis, the persistent use of which has been shown to be associated with neuropsychological decline in childhood through midlife [1].

Reference:

1: Meier MH, et al. Persistent cannabis users show neuropsychological decline from childhood to midlife. Proc Natl Acad Sci U S A. 2012 Oct 2;109(40):E2657-64. PubMed PMID: 22927402