CBN, or Cannabinol, is an oxidative degradation product of THC. It may be caused by improper storage or curing and extensive processing. It forms when THC is exposed to UV light and oxygen over time. CBN contains some psychoactive properties, about 10% strength of THC.
Some researchers believe that CBN enhances dizziness and disorientation effects a user may experience. Research has also found that is reduces heart rate and may cause feelings of grogginess.