if youre still determined to do it, make sure you dont stop taking your lamictal unless you taper off, and wait until youre off the zyprexa at least one week. there seems to be some side effects with lamictal that causes skin rashes and/or necrosis when the dose is changed too suddenly.
also, this goes without saying, but make sure you test your mdma, and keep the dose reasonable (100mg-150mg). if you dont feel it, then dont take more, just accept that you cant roll on these meds. and if you take the lamictal for mood stabilization instead of as an anti-epileptic, you may want to treat mdma as a psychedelic (set and setting) to reduce the risks of a psychotic episode.
you said that your first roll resulted in a psychotic episode for 2 weeks. you may feel better now, and it may not happen again with pure stuff at a reasonable dose, but it also may cause your lamictal to stop working properly during the recovery period when you have no serotonin left. also, avoid 5-htp due to possible respiratory depression (like ssris and lamictal), stick to high tryptophan foods instead.
but really, maybe mdma is not the drug for you
one more thing: an anecdotal report from someone mixing lamictal and mdma
http://wiki.answers.com/Q/Can_you_take_lamictal_and_ecstasy_together