Each year, Americans spend billions of dollars on self-improvement books, CDs, seminars, coaching, and stress-management programs to become better, more sociable, effective, compassionate, and charismatic versions of themselves. But beneath theories on what drives people to change, there’s a more fundamental question debated by psychologists: Can personality even be changed in the first place?
I don't think it's a question of personality. Not the core traits, in any event. Personality is defined as "a set of qualities that make a person (or thing) distinct from another." I can practice mindfulness, work my to-do list religiously, and get to bed at a decent hour every night, but that may not change the fact that I am fundamentally a five alarm asshole.
Therapy might help you change your personality. Being a practicer of GTD and walking on hot coals at a Tony Robbins seminar, all that gets you is lots of free time to focus on your third degree burns.
That said, if you're not an asshole at your core, the margin you can create in your life by putting systems and practices in place to get things off your plate may bring you back from the brink if you're leaning in a decidedly sphincterous direction (Hey! I made a word!)
If you think you need help, start with why you think you do. Then decide if you need professional help.