Rudolf Dreikurs himself was a musician. He played a number of instruments (piano, cello, violin, viola) and composed some classical music, and music was positive and dominant in his personal life. As a psychiatrist, he understood that music requires social sharing, not only between the listener and the performing artist, but if two or more performers play together, they need to cooperate. People with psychological disorders lack this cooperative sharing (as described by Adlerian psychology). The process of beating rhythms together or playing tunes together with others helps increase Social Interest (a key Adlerian concept). Dreikurs found music therapy with very disturbed children and adults often to be able to reach clients far more effectively than verbal 'talk therapy.'