It utilizes the body's natural ability to heal itself boosting the amount of energy focused on meaningful individual points.
For depression, anxiety, PTSD, and other issues, a practice called Jin Shin Jyutsu has been found by some to be effective for relief. Mary Murmeister popularized it back in the 1950s after studying in Japan.
The video below does an excellent job of explaining how it works and what fingers yield what results. Some fingers alleviate emotional stressors, like fear and anxiety. Other fingers focus on different problems.