This drug is for the GAD, but not if it's just for the insomnia. If it helps with the GAD it will apparently help with the insomnia, but antidepressants aren't sleep aids. As the above suggests, melatonin is for sleep. A lot of people are put on drugs that have an unwanted side effect of making people sleepy, but that doesn't make it a good choice for sleeplessness.
My Dr. told me to use Melatonin for sleeping. It is a natural sleep aid. I take 10mg at night an hour before I sleep and that works for my terrible insomnia. Hope this helps.