I've been on Seroquel XR for about 7 months. I'm at 600mg at nite. If you have insomnia (I do) it will go a long way towards getting it under control. I'm experiencing some weight gain. I don't really care about that, I'd rather be fat and happy. Probably the worst side effect I experience is the Restless Leg Syndrome. Sometimes as I lie down to sleep at night it'll make me nuts. I don't seem to experience any fogginess or loss of concentration during the day. I drive a dump truck for a living so anything that caused me to be a "Zombie" would be a problem. I also take Buspar for anxiety.