No one medication works the same for two people. So naturally, amitriptyline will work for some people and will not work for others.
It worked for me, but I think it worked a little too well. Because when I woke up, I continued to feel drowsy, sleepy and confused for several hours. I tried dealing with it for a while and then decided that I would be better off on another insomnia medication.
I'm not holding this against amitriptyline though. The medication was not formulated of insomnia. It's anti-depressant and its use for insomnia is an off-label use.