Abnormal can only be defined in relation to the term NORMAL, about which there is probably more disagreement than anything else in PSYCHOLOGY. In whatever sense it is used abnormal implies divergence from what is normal. It is generally used to describe someone's behaviour when it disturbs the regular course of his everyday life, or that of other people. People who believe they are Jesus Christ or who lie in a trance for days on end would be called abnormal by most mental health professionals. However, there is an important school of thought which believes that much, if not all, of the behaviour described as abnormal can be found in normal people from time to time, that mental institutions may be a convenient way for a society to get rid of people who are socially troublesome, that a society can itself in some sense be psychologically abnormal (the clearest example being Nazi Germany), and that 'going crazy' may be a way of escaping intolerable social conditions. See FLIGHT INTO ILLNESS.