Insomnia Support Group
Insomnia is a symptom, rather than a disease, and is characterized by inadequate quantity or quality of sleep. People with insomnia complain of difficulty falling or staying asleep, which results in significant impairment of daytime functioning. Insomnia is categorized as transient (shorter than one week), short-term (one to three weeks) or chronic (longer than three...
https://en.wikipedia.org/wiki/Mirtazapine
Anyone of those should of course be prescribed by your doctor. For me, as I had checked a lot of herbal things and I had insomnia due to anxiety being able to sleep was the major issue.