Many insomniacs swear by cannabis as a way to help them sleep – while many scientific studies have found that THC actually exacerbates sleep problems. A new study published last week in Addiction might explain why. Researchers from the University of Southern California’s Keck School of Medicine found that for young adults with pre-existing depression or anxiety, cannabis improved sleep. For those without pre-existing mental health conditions, it created more sleep problems. Read the article here.