In short, there can be different perspectives, broader or narrower, dealing with particular aspects of people - the biological, psychodynamic, societ… - Thaddeus E. Weckowicz

The behaviourist motto is "cure the symptoms and you have eliminated the neurosis." Consequently, the behaviour therapist's approach is straightforward. He deals with definite complaints of patients such as fears of certain situations, tics, or obsessional thoughts, which are considered by him to be bad habits. His remedy for them is to use definite and explicit retraining procedures.

In recent years, the studies of the effects of drugs on the behavior of animals have been playing an increasingly important role. Animal studies have been an advantage over studies with human subjects because better control of experimental variables and a possibility of using a wider range of the doses. It is also permissible to administer toxix compounds to animals. One can interfere surgically with various parts of the central nervous system while investigating the effects of the drugs. The whole field of comparative psychopharmacology has been recently reviewed

When one turns to psychological models of mental illness, one finds that the psychodynamic model of human mind and of mental disease is also of considerable antiquity. Thus, Empedocles of Agrigentum (490-430 B.C.) from whom Hippocrates took the theory of four elements, stressed the importance of emotions of love and hate as the controlling agents of human behavior and of physiological functions.