My husband is a recovering meth addict and it took about a year for him to stabilize. But, he was also smoking (cigarettes), drinking a LOT of soda, taking ambien for sleeping, eating a metric assload of junk food.
It seems that when he quit smoking, weaned off the caffeine and started focusing on how he was eating, things started to fall into place.
For me personally, (not someone coming from a stimulant addiction), what I eat and put in my body has such a HUGE effect on how I feel and how much energy I have. I've realized how sensitive I am to sugar and gluten and after cutting those out, it's been like the veil has been lifted. Not saying it's your diet, but don't be afraid to consider all angles and possibilities.
One thing I've noticed is that there are a few people here who were prescribed seroquel. He's also taking that for sleeping. Just an interesting observation.