I tried it for migraine prevention but couldn't tolerate more than 25 mg without some side effect I forget now. But it did help with sleep. However I no longer need it (am on plenty of very sedating clozapine) and when we tried to stop I stopped sleeping through the night. I don't lower meds in the summer because of mania but when fall comes if I'm relatively stable I'm going to get off it even if I have to break my tiny pills into 4ths. I've been on it for 4 years at a subtherapeutic dose and my body just needs to adapt. (If migraines get worse I'll go back on but it is not really helping mood).