Cannabis has become a go-to-sleep aid, but safety evidence is lacking. IRA_EVVA/iStock via Getty Images Plus For millions of people, cannabis has become the unofficial prescription for lost sleep. But what feels like a solution may be quietly making the problem worse. Consider these two cases: She is 15 and has been lying in bed for the past hour. It is past midnight, and her brain will not quiet down. Her school bus comes at 6:20 a.m. She is getting anxious, knowing that she needs to wake up i