Some 30-40% of the people with a mental disorder suffer from at least two mental disorders (Wittchen and Jacobi, 2005; see also Chapter 1). Co-morbidities of mental and physical disorders are also frequent (Harter et al., In the United States, for example, persons with a severe mental disorder, in combination with a physical health problem, have a benefit recipiency rate of over 70% - twice the recipiency rate of people with severe mental disorders who do not suffer from a physical problem.