Impostor syndrome (also spelled imposter syndrome, also known as impostor phenomenon or fraud syndrome) is a term coined in the 1970s by psychologists and researchers to informally describe people who are unable to internalize their accomplishments. Despite external evidence of their competence, those exhibiting the syndrome remain convinced that they are frauds and do not deserve the success they have achieved. Proof of success is dismissed as luck, timing, or as a result of deceiving others into thinking they are more intelligent and competent than they believe themselves to be. Notably, impostor syndrome is particularly common among high-achieving women, although some studies indicate that both genders may be affected in equal numbers.
The impostor syndrome tends to be studied as a reaction to certain stimuli and events. It is not perceived to be a mental disorder among people, but it has been the topic of research for many psychologists. Though traditionally perceived as an ingrained personality trait, impostor syndrome has more recently been studied as a reaction to certain situations. Under this interpretation, it is a response experienced by many different people to situations that prompt such feelings. Though certain people are more prone to impostor feelings, experience them more intensely than most, and can be identified through the use of personality scales, evidence does not support impostor syndrome to be a distinct personality trait.
The term "impostor syndrome" first appeared in an article written by Pauline R. Clance and Suzanne A. Imes who observed many high-achieving women tended to believe they were not intelligent, and that they were over-evaluated by others.
In high-achieving women
Imes and Clance found several behaviours of high-achieving women with imposter syndrome:
- Diligence: Gifted women often work hard in order to prevent people from discovering that she is an "impostor". This hard work often leads to more praise and success, which perpetuates the impostor feelings and fears of being "found out". The “impostor” women may feel they need to work two or three times as hard, so over-prepare, tinker and obsess over details, says Young. This can lead to burn-out and sleep deprivation.
- Feeling of being phony: A woman with impostor feelings often attempts to give supervisors and professors the answers that she believes they want, which often leads to an increase in feeling like she is "being a fake".
- Use of charm: Connected to this, gifted women often use their intuitive perceptiveness and charm to gain approval and praise from supervisors and seek out relationships with supervisors in order to help her increase her abilities intellectually and creatively. However, when the supervisor gives her praise or recognition, she feels that this praise is based on her charm and not on ability.
- Avoiding display of confidence: Another way that a woman can perpetuate her impostor feelings is to avoid showing any confidence in her abilities. A woman dealing with impostor feelings may believe that if she actually believes in her intelligence and abilities she may be rejected by others. Therefore, she may convince herself that she is not intelligent or does not deserve success to avoid this.
Psychological research done in the early 1980s estimated that two out of five successful people consider themselves frauds and other studies have found that 70 percent of all people feel like impostors at one time or another. It is not considered a psychological disorder, and is not among the conditions described in the Diagnostic and Statistical Manual of Mental Disorders. The term was coined by clinical psychologists Pauline Clance and Suzanne Imes in 1978.
People who have reportedly experienced the syndrome include screenwriter Chuck Lorre, best-selling writer Neil Gaiman, best-selling writer John Green, comedian Tommy Cooper, business leader Sheryl Sandberg, US Supreme Court justice Sonia Sotomayor, and actress Emma Watson.
Albert Einstein might have suffered from the syndrome near the end of his life: a month before his death, he reportedly confided in a friend, saying "the exaggerated esteem in which my lifework is held makes me very ill at ease. I feel compelled to think of myself as an involuntary swindler."
The impostor syndrome is particularly common among high-achievers. Another demographic group that often suffers from this phenomenon is African Americans. Being the beneficiary of affirmative action may cause a person who belongs to a visible minority to doubt their own abilities and suspect that their skills were not what allowed them to be hired. Impostor syndrome has been commonly reported by graduate students and scientists beginning tenure track positions.
Impostor syndrome is not a formal mental disorder and does not have a standard definition, therefore there has not been a clear consensus as to treatment options available.  The syndrome has affected approximately 70% of the population world wide,  however often goes unrecognized.  If it is not addressed, victims can develop anxiety, stress, low self-confidence, depression, shame and self-doubt.     People who suffer from impostor syndrome tend to reflect and dwell upon extreme failure, mistakes and negative feedback from others. If not addressed, impostor syndrome can limit exploration and the courage to delve into new experiences, in fear of exposing failure. 
A number of management options are available to ease impostor syndrome. The most prominent is to discuss the topic with other individuals early on in the career path.   Mentors can discuss experiences, where impostor syndrome was prevalent.  Most people who experience impostor syndrome are unaware that others feel inadequate as well. Once the situation is addressed, victims no longer feel alone in their negative experience. It is also noted, that reflecting upon impostor feelings is key to overcoming this burden.  Making a list of accomplishments, positive feedback and success stories will also aid to manage impostor syndrome.  Finally, developing a strong support system, who provides feedback on performance and has discussions about imposter syndrome on a regular basis is imperative for those experiencing impostorship.  
Coherence therapy holds that unconscious emotional learning requires a person to act and respond with certain behaviors, moods, feelings, or beliefs. Unlike cognitive therapy, coherence therapy asserts that it can address our most fundamental learning stored in the sublimbic, right-hemispheric, and emotion-processing areas of the brain, which other talking psychotherapy and rational countermeasures cannot reach. Coherence therapists claim that effective treatment of imposter syndrome requires showing the person through experiential juxtapositions that the self-deprecation does not match the person's core emotional understanding.[page needed][need quotation to verify]
Writing therapy allows the person to organize their thoughts in writing. The written record of the person's objective accomplishments can enable the person to associate those accomplishments with reality, rather than simply dismissing the accomplishments internally. The written record can also remind the person of those accomplishments later. By these methods, writing therapy attempts to alleviate the person's sense of inadequacy.[page needed][need quotation to verify]
- Illusory superiority
- Jonah complex
- Dunning–Kruger effect
- Explanatory style
- Tall poppy syndrome
- Clance, Pauline Rose; Imes, Suzanne A. (1978). "The imposter phenomenon in high achieving women: Dynamics and therapeutic intervention." (PDF). Psychotherapy: Theory, Research & Practice 15 (3): 241–247. doi:10.1037/h0086006. Retrieved 19 February 2015.
- Laursen, Lucas. "No, You're Not an Impostor". Science Careers. Web. 23 Oct. 2013.
- McElwee, Rory O'Brien; Yurak, Tricia J. (2010). "The Phenomenology Of The Impostor Phenomenon". Individual Differences Research. Social Sciences Full Text (H.W. Wilson) 8 (3): 184–197.
- High achievers suffering from imposter syndrome News.com Dec 10 2013
- Neil Gaiman's commencement speech to the University of the arts graduating class of 2012 Philadelphia,
- Always leave them laughing (biography of Tommy Cooper) Fisher, John 2007
- Women who feel like frauds Forbes October 2011
- Emma Watson: I suffered from imposter syndrome after Harry Potter Now magazine 2011
- Time Bandits The New Yorker 2005
- Langford, P.; Clance, P. R. (1993). "Impostor Phenomenon: Recent Research Findings Regarding Dynamics, Personality and Family Patterns and their Implications for Treatment" (PDF). Pschotherapy 30 (3): 495–501. doi:10.1037/0033-318.104.22.1685.
- Vera, Elizabeth M.; Vasquez, Veronica; Corona, Rebecca (2006). "Women of Color". In Yo Jackson. Encyclopaedia of Multicultural Psychology. SAGE knowledge. Thousand Oaks, CA: SAGE Publications, Inc. pp. 475–80. Web. 1 October 2012.
- Craddock; Birnbaum; Rodriguez; Cobb; Zeeh (2011). "Doctoral students and the impostor phenomenon: Am I smart enough to be here?". Student Affairs Research and Practice.
- Clark, M., Vardeman, K., & Barba, S. (2014). Perceived inadequacy: A study of the impostor phenomenon among college and research librarians. College & Research Libraries, 75(3), 255–271
- Brookfield (1978). "Understanding and responding to the emotions of learning. In The skillful teacher: On trust, technique and responsiveness in the classroom".
- Dudău, D. P. (2014). The Relation between Perfectionism and Impostor Phenomenon. Procedia - Social and Behavioral Sciences, 127(0), 129–133.
- Faulkner (2015). "Reflections on the impostor phenomenon as a newly qualified academic librarian".
- Want, J., & Kleitman, S. (2006). Impostor phenomenon and self-handicapping: Links with parenting styles and self-confidence. Personality and Individual Differences, 40(5), 961–971.
- Vergauwe, J., Wille, B., Feys, M., De Fruyt, F., & Anseel, F. (2015). Fear of being exposed: The trait-relatedness of the impostor phenomenon and its relevance in the work context. Journal Of Business And Psychology, (3), 565.
- Kumar; Jagacinski (2006). "Imposters have goals too: The imposter phenomenon and its relationship to achievement goal theory". Personality and Individual Differences: 147–157.
- Queena (2013). "The impostor phenomenon: Overcoming internalized barriers and recognizing achievements". Vermont Connection: 3441–3452.
- Hutchins, H. M. (2015). Outing the imposter: A study exploring imposter phenomenon among higher education faculty. New Horizons In Adult Education & Human Resource Development, 27(2), 3-12.
- Ecker, Bruce (2013). Unlocking the Emotional Brain. New York: Routledge.
- Moore, Lynda L. (1986). Not as Far as You Think: The Realities of Working Women. Lexington, Mass.: Lexington Books.
- Clance, Pauline Rose. "Impostor Phenomenon"
- "Feeling like a fraud". YorkU (alumni magazine) (York University): 9. October 2006
- The Impostor Syndrome
- Impostor syndrome BBC Radio 4, Woman's Hour, 15 Feb 2006
- Pauline Clance's Impostor Phenomenon Reference List
- Overcoming my Biggest Roadblock, Myself, presented at the Women in Advanced Computing 2012 conference
- Caltech Counseling Center
- Julie Pagano, Pycon 2014 presentation It's Dangerous to Go Alone: Battling the Invisible Monsters in Tech