It's true that Ativan and other benzos can be addicting. However in people that do not have addictions in their history there is little risk of becoming addicted. Addiction should be separated from tolerance, which is normal process that a given doseage will sometimes need to be increased to achieve the desired effect. Tolerance can be avoided by taking meds only when needed (couple times a week?). Withdrawal can be experienced in anyone on medium to high doses of benzos and is avoided by decreasing the benzo gradually over time to stop. Withdrawal is a physiological phenonmenon and does not indicate addiction.

There are plenty of meds useful for sleep that are not habit-forming. Amitryptiline like you mentioned, is an older tricyclic antidepressant with sedating properties. Many docs don't like to prescribe tricyclics though because they are so easy to OD on. Benadryll (diphenhydramine) is available in many over the counter sleep aids (Tylenol PM). My favorite is trazodone (Desyrel) which I take. It is also a sedating antidepressant taken in small doses that is safe and in-expensive. In some people it may cause grogginess in the am though. No way to tell for sure unless you try it. I sometimes take clonidine (Catapress) at night as I have difficulty settling my mind due to my ADHD.