Seems like it's quick-draw. Neither one really has shown strong enough psionic defenses against the other's powers.
So either Meggan makes Karma feel suicidal depression, or Karma simply possesses and mind controls Meggan.
I think the edge goes to Karma though, as her possession seems to have more of an immediate effect than Meggan's empathic powers.
Meggan just grabs the psionic energy and snaps it. Are we forgetting who Meggan is?
She held back the universe destroying waves from blah blah Nexus crystal with her bare hands. Lol. She is as powerful as where she is and can turn into anything. IIRC she poofed into a Silver Surfer like thing for a panel or something.