"i&#039;ve been taking klonopin for several years, but slowly building up a tolerance.  doc suggested trying mirtazapine.  made me very groggy the first night, and i fell asleep quickly.  however, i woke several times during the night, and only ended up getting 3-4 hours of sleep (and felt very groggy the next day).  i might be experiencing some withdrawal from the klonopin).  hard to know, but sleep has only gotten worse since the first night, so will likely try something else."