GPC and CDP affect the very same pathway, but GPC is actually one step higher on the ladder (closer to the end synthesis, e.g. aceytcholine). so it affords you, if you will, a wider view of things than does CDP.. sometimes it's the most breath taking views that are the hardest to choke on.
the CDP also generates a uridine molecule which has secondary dopamine effects (even though they may be weak). you can try a dopaminergic supplement, like shilajit or ginkgo, and see what that does for you. be careful to back off the choline even more, because both shilajit and ginkgo are AChEs.
in addition to being a lower precursor and having dopamine effects, it's worth mentioning the CDP has a much harder time crossing the blood-brain-barrier and these things together might explain why it doesn't make you as irritable as GPC
if you dig deep enough into the literature you'll invariably find ties between each illness and every other neurotransmitter. you'll resolve yourself into a thoroughly hegelian metaphysic. these two linked studies are about choline and PTSD, about altered binding in PTSD patients as well as a second study for the permanent stress-induced induction of c-Fos and its negative regulation of the muscarinic loop. PTSD has a lot in common with BPD, it's a sort of mini-BPD-phreniform disorder if you will. i would look into glutamate and neurohormones too, you'll find a lot of surprising ties there. it might explain why green tea (glutamate releaser) doesn't always make me as chill as curcumin (release inhibitor)
http://www.nature.co...s/393373a0.html
https://digital.libr...ndle/2440/56315
and i suppose you could continue the GPC and hope for the side effects to just go away, but you do so at your own risk. i am not recommending it