

Defence mechanism
In psychoanalytic theory, defense mechanisms are unconscious psychological processes that protect the self from anxiety-producing thoughts and feelings related to internal conflicts and external stressors. Defences are automatically used to protect ourselves from threats and affects to maintain psychological balance and homeostasis. Defenses are automatic responses to external stressors or internal conflicts.
Healthy people have a fully developed sense of "object constancy", knowing that bad and good can exist at the same time in the same person. A defense mechanism can become pathological when its persistent use leads to maladaptive behaviour such that the physical or mental health of the individual is adversely affected. Among the purposes of defense mechanisms is to protect the mind/self/ego from anxiety or to provide a refuge from a situation with which one cannot cope at that moment.
Definition from Wikipedia – Defence mechanism
Sigmund Freud
Sigmund Freud (born Sigismund Schlomo Freud; 6 May 1856 – 23 September 1939) was an Austrian neurologist and the founder of psychoanalysis, a clinical method for evaluating and treating pathologies arising from conflicts in the psyche through dialogue between patient and psychoanalyst, and the distinctive theory of mind and human agency derived from it.
In creating psychoanalysis Freud introduced therapeutic methods such as free association, the interpretation of dreams, and the analysis of transference phenomena that arise in the clinical setting. Freud's redefinition of sexuality to include infantile stages led him to formulate the Oedipus complex as the central tenet of psychoanalytical theory. His analysis of dreams as wish fulfillments provided him with models for the clinical analysis of symptom formation and the underlying mechanisms of repression. Accordingly, on this basis, Freud elaborated his theory of the unconscious and went on to develop a model of psychic structure comprising id, ego, and superego (a tripartite model of the mind). Freud postulated the existence of libido (sexualised psychic energy), with which mental processes and structures are invested and that generates...
Definition from Wikipedia – Sigmund Freud
Anna Freud
Anna Freud ( FROYD; Austrian German: [ˈana ˈfrɔʏd]; 3 December 1895 – 9 October 1982) was a British psychoanalyst of Austrian Jewish descent. She was born in Vienna, the sixth and youngest child of Sigmund Freud and Martha Bernays. She followed the path of her father and contributed to the field of psychoanalysis. Alongside Hermine Hug-Hellmuth and Melanie Klein, she may be considered the founder of psychoanalytic child psychology.
Compared to her father, her work emphasized the importance of the ego and its normal "developmental lines" as well as incorporating a distinctive emphasis on collaborative work across a range of analytical and observational contexts.
After the Freud family were forced to leave Vienna in 1938 with the advent of the Nazi regime in Austria, she resumed her psychoanalytic practice and her pioneering work in child psychoanalysis in London, establishing the Hampstead Child Therapy Course and Clinic in 1952 (later renamed the Anna Freud National Centre for Children and Families) as a centre for therapy, training and research work.
Definition from Wikipedia – Anna Freud