The new Psionics rules use Concentration to activate and maintain disciplines. The PDF says they use the same rules as spellcasting, and that you can only concentrate on one discipline at a time. However it does not specify whether you can concentrate on both a single discipline and a single spell at the same time. IMO this is left up to the DM to decide.

Does a character have a single "concentration slot" which can be used for either a spell or a discipline? Or can a character concentrate on both a single discipline and a single spell at the same time?

My answer as DM is to allow the "double concentration" as disciplines are distinct from spells. What are your thoughts?