colin knows from experience how messy, horrible, confusing & Stressful anxiety and depression can be
Since Colin talks from experience, you know he has been through a lot. Maybe not as much as many of his clients (domestic abuse for instance), but enough to really understand what it's like to be stuck, unable to be positive, feeling worthless, useless and weak, confused and emotional, feeling overwhelmed for no reason and just wanting to hide under the blankets or dull the pain with meaningless TV.
He understands, not from reading books (although he has read plenty), but from the inside-out, how hard it is to make progress when you don't feel like doing anything which may help, or the negative thinking gets the better of you and you cannot face using your willpower to take the next step in your attempts to move your life forward.
That's part of the reason he wants to take the anxiety of getting help while not knowing if you're paying for something that doesn't work...