They cannot save another because, given the same circumstances, they could not save themselves. Christian psychology is the application of Scripture to life's problems. When you discipline your child, you are doing Christian psychology. When you worship God, you are doing Christian psychology. When you think about drugs, alcoholism, or homosexuality, you should be doing Christian Psychology.
Confusion arises between Christian psychology and secular psychology because of the medical model.
This model states that most of life's problems can be reduced to biochemical abnormalities. As a result, personal responsibility is either diminished or altogether absent. Drunkenness is always sin, never sickness. Christians must understand that secular psychology is in fact a religion whose priests and ministers are disguised as medical doctors or other type health professionals who practice a systemized set of ungodly doctrines.