Teens who use synthetic marijuana are more likely to be injured or engage in violent behaviors than their peers who only use marijuana, a new study concludes.

Using synthetic marijuana, also known as K2 or Spice, also increases teens’ risk of being victims of sexual or physical dating violence, according to HealthDay. Teens who have tried synthetic marijuana are more likely to be threatened or injured with a weapon on school property, researchers from the Centers for Disease Control and Prevention report in Pediatrics.

Synthetic marijuana is a mixture of herbs, spices or shredded plant material that is typically sprayed with synthetic compounds known as cannabinoids that are chemically similar to THC, the psychoactive ingredient in marijuana. Although these products are often marketed as “safe” alternatives to marijuana, they may affect the brain much more powerfully than marijuana. Their effects can be unpredictable and severe.