What I can say, from personal experience, is that if you're predisposed to melancholic depression, and struggle to put on weight, then Quetiapine can be very useful.
According to literature, it dampens the levels of cortisol and ACTH. Arguably, it is one of the strongest drugs to do so, because it blocks H1, a1, and 5-HT2 receptors, all of which have been shown to have a positive effect on stress hormones.
it is also metabolised to another chemical (norquetiapine) which blocks Muscarinic receptors (also involved in cortisol release) and inhibits the reuptake of norepinephrine. And since quetiapine already blocks alpha adrenoceptors, the net result would be increased activation of beta adrenoceptors, which actually have a direct positive effect on skeletal muscle growth itself.
In terms of side effects, thankfully Quetiapine has only very weak effects on prolactin, and at least in my case, blood tests have shown that a lower dosage causes no disruption in blood sugar levels.