insomnia
"I have no problem going to sleep (9 or 10).  I'll will quite frequently wake up at 1:00am or 2:00am and cannot get back to sleep. When this happens I take 10mg and I will quickly go back to sleep until 4:30am or 5:00am which is the time I get up. If I get 6 to 7 hour of total sleep without waking up I won't take the Sonata ."