Editing Defence mechanism (section)

== Theories and classifications ==
In the first definitive book on defence mechanisms, ''The Ego and the Mechanisms of Defence'' (1936),<ref name="autogenerated1937">Freud, A. (1936). ''The Ego and the Mechanisms of Defence'', London: Hogarth Press and Institute of Psycho-Analysis. (Revised edition: 1966 (US), 1968 (UK))</ref> [[Anna Freud]] enumerated the ten defence mechanisms that appear in the works of her father, [[Sigmund Freud]]: [[Psychological repression|repression]], [[Regression (psychology)|regression]], [[reaction formation]], [[Isolation (psychology)|isolation]], [[Undoing (psychology)|undoing]], [[Psychological projection|projection]], [[introjection]], [[self-harm|turning against one's own person]], reversal into the opposite, and [[Sublimation (psychology)|sublimation]] or [[Displacement (psychology)|displacement]].<ref name="Szondi1956">Lipot Szondi (1956) [http://www.szondiforum.org/II.%20Szondi%20Ego%20Defenses%20and%20Sublimination.pdf ''Ego Analysis''] Ch. XIX, translated by Arthur C. Johnston, p. 268</ref>

Sigmund Freud posited that defence mechanisms work by distorting [[Id (psychology)|id]] impulses into acceptable forms, or by unconscious or conscious blockage of these impulses.<ref name="autogenerated1937"/> Anna Freud considered defense mechanisms as intellectual and motor automatisms of various degrees of complexity, that arose in the process of involuntary and voluntary learning.<ref>{{cite book |last= Romanov|first= E.S. |date= 1996 |title=Mechanisms of psychological defense: genesis, functioning, diagnostics}}</ref>

Anna Freud introduced the concept of signal anxiety; she stated that it was "not directly a conflicted instinctual tension but a signal occurring in the ego of an anticipated instinctual tension".<ref name="autogenerated1937"/> The signalling function of anxiety was thus seen as crucial, and biologically adapted to warn the organism of danger or a threat to its equilibrium. The anxiety is felt as an increase in bodily or mental tension, and the signal that the organism receives in this way allows for the possibility of taking defensive action regarding the perceived danger.

Both Freuds studied defence mechanisms, but Anna spent more of her time and research on five main mechanisms: repression, regression, projection, reaction formation, and sublimation. All defence mechanisms are responses to anxiety and how the consciousness and unconscious manage the stress of a social situation.<ref name="Hock, Roger R 2013">Hock, Roger R. "Reading 30: You're Getting Defensive Again!" Forty Studies That Changed Psychology. 7th ed. Upper Saddle River: Pearson Education, 2013. 233–38. Print.</ref>

*''Repression'': the exclusion of unacceptable desires and ideas from consciousness, though in certain circumstances they may resurface in a disguised or distorted form
*''Regression'': falling back into an early state of mental/physical development seen as "less demanding and safer"<ref name="Hock, Roger R 2013"/>
*''Projection'': possessing a feeling that is deemed as socially unacceptable and instead of facing it, that feeling or "unconscious urge" is seen in the actions of other people<ref name="Hock, Roger R 2013"/>
*''Reaction formation'': acting the opposite way that the unconscious instructs a person to behave, "often exaggerated and obsessive". For example, if a wife is infatuated with a man who is not her husband, reaction formation may cause her to – rather than cheat – become obsessed with showing her husband signs of love and affection.<ref name="Hock, Roger R 2013"/>
*''Sublimation'': seen as the most acceptable of the mechanisms, an expression of anxiety in socially acceptable ways<ref name="Hock, Roger R 2013"/>

[[Otto F. Kernberg]] (1967) developed a theory of borderline personality organization of which one consequence may be [[borderline personality disorder]]. His theory is based on ego psychological [[object relations theory]]. Borderline personality organization develops when the child cannot integrate helpful and harmful mental objects together. Kernberg views the use of primitive defence mechanisms as central to this personality organization. Primitive psychological defences are projection, denial, dissociation or splitting and they are called borderline defence mechanisms. Also, devaluation and projective identification are seen as borderline defences.<ref name="pmid4861171">{{cite journal |author=Kernberg O |title=Borderline personality organization |journal=J Am Psychoanal Assoc |volume=15 |issue=3 |pages=641–85 |date=July 1967 |pmid=4861171 |doi= 10.1177/000306516701500309|s2cid=32199139 }}</ref>

[[Robert Plutchik]]'s (1979) theory views defences as derivatives of basic [[emotions]], which in turn relate to particular diagnostic structures.  According to his theory, reaction formation relates to joy (and manic features), denial relates to acceptance (and histrionic features), repression to fear (and passivity), regression to surprise (and borderline traits), compensation to sadness (and depression), projection to disgust (and paranoia), displacement to anger (and hostility) and intellectualization to anticipation (and obsessionality).<ref>Plutchik, R., Kellerman, H., & Conte, H. R. (1979). A structural theory of ego defences and emotions. In C. E. Izard (Ed.), Emotions in personality and psychopathology (pp. 229–-257). New
York: Plenum Press.</ref>

The ''Diagnostic and Statistical Manual of Mental Disorders'' (''[[DSM-IV]]'') published by the [[American Psychiatric Association]] (1994) includes a tentative diagnostic axis for defence mechanisms.<ref>American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author.</ref> This classification is largely based on Vaillant's hierarchical view of defences, but has some modifications. Examples include: denial, fantasy, rationalization, regression, isolation, projection, and displacement. However, additional defense mechanisms are still proposed and investigated by different authors. For instance, in 2023, time distortion was proposed in a publication as a newly identified ego defense.<ref>{{Cite journal |last=Fowler |first=Alexander |date=2023 |title=On the Distortion of Time: An Unexplored Ego Defense Mechanism |url=https://www.researchgate.net/publication/377399205 |journal=International Research Journal of Modernization in Engineering, Technology, and Science |issn=2582-5208}}</ref>

Different theorists have different categorizations and conceptualizations of defence mechanisms. Large reviews of theories of defence mechanisms are available from Paulhus, Fridhandler and Hayes (1997)<ref>Paulhus, D.L., Fridhandler B., and Hayes S. (1997). Psychological defense: Contemporary theory and research. In {{cite book |author1=Briggs, Stephen |author2=Hogan, Robert Goode |author3=Johnson, John W. |title=Handbook of personality psychology |publisher=Academic Press |location=Boston |year=1997 |pages=543–579 |isbn=978-0-12-134646-1 }}</ref> and Cramer (1991).<ref>Cramer, P. (1991). The Development of Defense Mechanisms: Theory, Research, and Assessment. New York, Springer-Verlag.</ref> The ''Journal of Personality'' published a special issue on defence mechanisms (1998).<ref>[http://onlinelibrary.wiley.com/doi/10.1111/jopy.1998.66.issue-6/issuetoc Special issue] [on defense mechanisms], ''Journal of Personality'' (1998), '''66''' (6): 879–1157</ref>