Clonazepam
"This stuff works great at first. I took it for both insomnia and mild anxiety, and within 20min I was so relaxed and could fall asleep like nothing. Unfortunately my tolerance built up so quickly; I went from 0.5mg a night to 2mg a night in just 2 months just for it to keep working. And coming off of it is extremely difficult. VERY heightened anxiety and terrible withdrawal symptoms. It took me nearly 2 months to get off it completely."