Original:  The experts used the terms apathy and abulia interchangeably and debated whether or not abulia was a discrete entity, or just a hazy gray area on a spectrum of more defined disorders.
Revised:  The experts used the terms "apathy" and "abulia" interchangeably and debated whether or not abulia was a discrete entity, or just a hazy gray area on a spectrum of more defined disorders.
Edit intent: fluency