Do you have insurance/do you have access to your plan's website? Usually you can find a list of behavioral health specialists on your plan, and they might say whether they are accepting new patients. That's how I found my doctors.
Also, 9/10 times you'll run into an answering machine. They do have patients throughout the day.

Just leave a message. If they don't call back, don't try again -- you don't want that doctor, then.