I have personally prescribed neurontin just a handful of times for insomnia, primarily in those who have substance abuse or cirrhosis of the liver; unfortunately, the feedback that I've gotten is that it hasn't really helped.   For those that have taken it for anxiety, I have gotten better feedback.  there are some who have told me they feel more dizzy and drowsy on it, but there is a subset of patients who do report improved anxiety.  I also like to use it to help with menopausal hot flashes, and I have pretty good feedback that it has helped provide relief from those.