Studies have shown that marijuana containing cannabidiol (CBD) can be effective for treating people with epilepsy. But it turns out other forms of marijuana, particularly synthetic versions, can actually cause seizures.

Scientists at the University of Tsukuba in Japan recently published a study that found that marijuana with very high THC content as well as the synthetic cannabinoid JWH-018 were shown to produce seizures in mice. JWH-018 is the primary component of the synthetic marijuana known as "spice." The scientists administered doses of both THC and JWH-018 to mice in a lab. They found that both compounds led to seizures in mice, but JWH-018 did so far more frequently. 

There are some issues with the study. As previously mentioned, many studies have shown that marijuana has the opposite effect on animals and humans and actually prevents seizures. The scientists said their experiment may have produced different results because "few of [the past studies] used EEG recordings to assess epileptic events and many of them induced seizures either electrically or pharmacologically, changing signaling pathways and brain states prior to cannabinoid application."

Another issue with this study is that amount of THC and JWH-018 administered to the mice represented extremely high doses. The amount of these compounds found in medicinal or recreational marijuana is usually considerably less than what the mice were exposed to. The scientists said, "It would be interesting in the future to also test lower doses, typically used medicinally or recreationally to determine whether the effect is lost or diminished." 

So this study may not fully prove that taking marijuana puts humans at greater risks of suffering from seizures. But this study just shows it's always good to do a little research before purchasing marijuana products, especially man-made ones.