Stanford University research psychologist Tracy Kuo, PhD. says,
It was thought by doctors for a long time that depression led to insomnia (inability to sleep), but now, in a recent study, experts are suspecting it’s the other way around and that it could be that insomnia leads to depression.
The study from 2013 was funded by the U.S. National Institute of Mental Health. The insomnia treatment relied on talk therapy, rather than sleep medication, for 66 patients.
There is existing evidence that symptoms of insomnia precede sypmtoms of depression by a few years, which could suggest that by specifically treating insomnia it can improve significantly the well-being of people with depression.
In a research review published in 2007 , hypnosis can help ease insomnia and may be useful in the treatment of nightmares, sleep terrors, nocturnal enuresis (bedwetting), and sleepwalking.
 Graci GM, Hardie JC. “Evidenced-based hypnotherapy for the management of sleep disorders.” Int J Clin Exp Hypn. 2007 55(3):288-302.