Defense Mechanisms (also known as defences) are unconscious psychological mechanisms that reduces anxiety arising from unacceptable or potentially harmful stimuli. Defences can be adaptive or maladaptive. Learning to identify and understand defenses is important in psychodynamic psychotherapy.

Less Adaptive Defenses

Type Definition Example Potential diagnosis
Conversion An internal psychological conflict is expressed as a physical symptom (e.g. - blindness, deafness, paralysis, or numbness). This phenomenon is sometimes called hysteria. John's arm becomes suddenly paralyzed after he was threatening to hit someone. Conversion disorder

Less Adaptive Defenses

Type Definition Example Potential diagnoses
Splitting Seeing others as being either all bad or all good. The ego preserves good feelings and avoids bad feelings by separating them into different people. Jane says says that all the male nurses are cold and insensitive, but the female doctors are warm and friendly. Borderline personality disorder
Projection Attributing one's own feelings to others. The ego protects itself by perceiving unacceptable thoughts, feelings, and fantasies as originating outside of the self. John wants to cheat on his wife, yet accuses his wife of being unfaithful. -
Projective identification Projective identification occurs when one person (A) projects a thought or feeling into another person (B) and then interacts with B to make B experience that projected feeling. Person A maintains an identification with the projected feeling. John is passed over for a promotion by his boss. Although he says that this is fine with him, his unconscious anger is so overwhelming that he projects it onto his boss, and intentionally comes in late to work for a whole month, until his boss is so angry that he fires him. John is projecting the rage onto his boss, and his boss unconsciously identifies with it and then fires John. -
Pathological idealization and devaluation Idealization and devaluation are natural results of a splitting defense. Jane thought that her therapist completely understood her while her husband was an idiot; but the next week it was the reverse. In this defense, the person who is idealized today may easily be devalued tomorrow. Borderline personality disorder
Denial* Behaving as if an aspect of reality does not exist. The ego protects itself from unacceptable feelings by disavowing the existence of that painful reality. John presents to a dermatologist complaining of acne and was found to have an enormous malformed tumour protruding from his cheek. Despite being told he has a tumour, the patient was so unable to process this that he denied its existence, and calls it a “pimple” instead. -
Dissociation Disrupting one's memory, identity, motor behaviour, and/or consciousness to cope with an event or avoid emotional stress. Dissociation allows the ego to avoid unacceptable thoughts and affects by disconnecting the self from aspects of one’s current reality. The individual will have incomplete or no memory of the traumatic event A victim of physical abuse suddenly appears detached, numb, and non-responsive when she sees her abuser on the street. Posttraumatic stress disorder, borderline personality disorder
Acting out Easing unacceptable feelings by behaving badly. John skips his therapy appointment after his last session revealed deep discomforts from his past. Another example is if someone threw tantrums because of something they did not like. Oppositional defiant disorder, antisocial personality disorder
Regression Reverting back to an earlier developmental stage. Going back to an earlier way of functioning in order to avoid the anxiety-provoking feelings prompted by a later developmental period. Up against four medical school exams, Jane returned to her parents' home, where they made her meals and did her laundry. Note that this defense is commonly used during periods of stress (e.g. - sickness/injury) by people who generally function at a very high level. Borderline personality disorder
Passive-Aggressive Avoiding conflict by expressing hostility covertly John is a disgruntled employee, and repeatedly shows up late to work, but won’t admit he is trying to get back at his boss. -

The more adaptive defenses tend to be based on repression. In repression-based defenses, all or part of the unacceptable thought or feeling is made or kept unconscious. Note that well-functioning people use repression-based defense mechanisms every day, and, when under stress, they may regress and transiently use splitting-based defense mechanisms.

More Adaptive Defenses

Type Definition Example Potential diagnoses
Isolation of affect Separating feelings from ideas and events. The ego represses the affect (emotion) but the thought remains conscious. The person seems devoid of feeling to others. Despite being devastated by his divorce, John said with a straight face that he had no feelings about having just been left by his wife. Depression, anxiety
Intellectualization Using facts and logic to avoid uncomfortable feelings. Similar to isolation of affect, this defense uses excessive thinking to replace painful or uncomfortable feelings. Unable to talk about feelings of anxiety about starting therapy, Jane read several books about psychotherapy and trauma, and began by the session by talking about the neuroanatomical underpinnings of trauma, rather than about her own emotions and feelings. Depression, anxiety
Rationalization Justifying behavior to avoid difficult truths. The ego addresses unacceptable feelings by coming up with reasons or justifications. John is fired from work, but tells his wife that it is for the best because he’d been unhappy at work for years. Depression, anxiety
Displacement Redirecting one's feelings or impulses to a neutral person or more acceptable object. After Jane is reprimanded by her boss, she returns home and criticizes her husband's cooking instead of confronting her boss directly. -
Somatization Transforming emotional conflicts into physical symptoms. Here a thought or affect is repressed and is experienced as a bodily sensation. John is extremely anxious about his upcoming date, and experiences stomach cramps the day before his date. Somatic disorders
Undoing The ego's chance at a “do-over.” The ego gets to reverse something it feels is unacceptable or uncomfortable. Jane stole merchandise at work and then gave a dollar to a homeless person on the street on her way home. -
Reaction formation Behaving in a manner opposite to one's actual feelings. The unacceptable emotion is reversed and experienced consciously as its opposite. This defense is different from undoing because the original emotion was never consciously experienced – it becomes the opposite before it becomes conscious, and thus doesn’t have to be “undone.” Jane the stepmother treats a stepchild with excessive nurturing and overprotection. However, she unconsciously resents the child. Histrionic personality disorder
Repression Involuntarily/unintentionally blocking upsetting feelings from entering the consciousness. Repression hides thoughts, feelings, and fantasies from consciousness, leading to forgetting and/or denial. Contrast this to suppression, which is the voluntary blocking of upsetting feelings (more adaptive). John does not remember going to family counselling during his parents' divorce 20 years ago. -
Turning against the self This defense substitutes the self for the object, particularly when it comes to negative affects. John was angry at his father for buying a new car rather than paying for his college education. Later in the school year, he is angry at himself for not doing as well as he could have during the semester. -
Identification The ‘“if you can’t beat them, join them” defense. Feelings such as jealousy and competitiveness are dealt with by internalizing aspects of the other person. Identification can be quite adaptive, for example when someone works in a productive way to emulate a mentor. Identification is a normal and important part of development during adolescence. A medical student struggling in medical school starts talking in mannerisms similar to another medical student who is more academically successful.
Excessive emotionality Thought content is repressed while affect remains present. This is a defense that is opposite of intellectualization and isolation of affect. Sometimes the high affect (emotion) substitutes for a repressed thought, while other times, it substitutes for another, even more anxiety-provoking emotion. Instead of telling her husband she was fired from her job, Jane cried for hours unconsolably. Histrionic personality disorder
Sexualization An individual take issues that are not sexual and makes them sexual to avoid deeper uncomfortable feelings. Adrift during her mother’s death, Jane began to flirt with her male trainer to avoid thinking about her mother. Histrionic personality disorder
Externalization People perceive internal conflicts as if they were external conflicts. Jane debates with her therapist about whether she should stay with her current boyfriend, after an ex-boyfriend texts her. Several months into therapy, she realizes she was ambivalent about getting married to her boyfriend in the first place (regardless of if the ex-boyfriend had texted or not). -

Most Adaptive (Mature) Defenses

Type Definition Example
Altruism Avoiding negative feelings by helping others. Dealing with the loss of a loved one by volunteering one time at a community centre
Humour Using humor to avoid uncomfortable feelings Making jokes to cope with a stressful event.
Sublimation Channeling impulses and emotions into more socially acceptable behaviors. This is the opposite of reaction formation. Instead of self-harming by cutting one's wrist, using an ice cube instead to feel pain.
Suppression Putting unwanted feelings aside to cope with reality. An Olympic athlete focuses on other training exercises to prevent anxiety about an upcoming match.


The mnemonic “Mature adults wear a SASH” can be used to remember the four mature defenses:
  • S - Suppression
  • A - Altruism
  • S - Sublimation
  • H - Humour

Projection typically involves three steps: 

  1. Person A experiences thoughts, feelings, or motivations (i.e., impulses) which he/she (unconsciously) finds “undesirable”
  2. Person A denies experiencing these undesirable impulses him/herself
  3. Person A imagines that Person B is experiencing these undesirable impulses


John becomes attracted to a coworker and begins having sexual dreams/fantasies about her. Because he believes that such fantasies are morally wrong, John cannot accept their existence. To protect himself, John projects these feelings onto his wife (unconsciously). He denies feeling any attraction towards his coworker and begins to believe that his wife is carrying on an affair.

Projective identification occurs when a person identifies with the impulses being projected onto them. It is similar to the idea of a self-fulfilling prophecy:

  1. Person A experiences impulses which he/she (unconsciously) finds “undesirable”
  2. Person A denies experiencing these undesirable impulses him/herself
  3. Person A imagines that Person B is experiencing these undesirable impulses
  4. Person B begins to experience the impulses that Person A imagines in them


Jane tells her therapist about how she was rejected from another job interview and begins feeling extreme disappointment and hopelessness. Because she believes that she must be upbeat and optimistic at all times, Jane cannot accept her own feelings. To protect herself, Jane unconsciously projects these feelings onto her therapist. She denies feeling any negativity and begins to believe that her therapist is disappointed in her and hopeless about her future. Although the therapist was initially moved to feel empathy for Jane's plight, he begins to feel increasingly frustrated and pessimistic about the situation. (The therapist's feelings and beliefs are likely being influenced by Jane's behavior, but the whole process occurs largely outside of the conscious awareness of either party.)