Neurosis is a class of functional mental disorders involving distress but neither delusions nor hallucinations, whereby behavior is not outside socially acceptable norms.1 It is also known as psychoneurosis or neurotic disorder, and thus those suffering from it are said to be neurotic. The term essentially describes an "invisible injury" and the resulting condition.
The term neurosis was coined by the Scottish doctor William Cullen in 1769 to refer to "disorders of sense and motion" caused by a "general affection of the nervous system". For him, it described various nervous disorders and symptoms that could not be explained physiologically. It derives from the Greek word "νεῦρον" (neuron, "nerve") with the suffix -osis (diseased or abnormal condition). The term was however most influentially defined by Carl Jung and Sigmund Freud over a century later. It has continued to be used in contemporary theoretical writing in psychology and philosophy.2
The American Diagnostic and Statistical Manual of Mental Disorders (DSM) has eliminated the category of "neurosis", reflecting a decision by the editors to provide descriptions of behavior as opposed to hidden psychological mechanisms as diagnostic criteria,3 and, according to The American Heritage Medical Dictionary, it is "no longer used in psychiatric diagnosis".4 These changes to the DSM have been controversial.5
There are many forms of neurosis: obsessive–compulsive disorder, anxiety neurosis, hysteria (in which anxiety may be discharged through a physical symptom), and a nearly endless variety of phobias as well as obsessions such as pyromania. According to C. George Boeree, professor emeritus at Shippensburg University, effects of neurosis can involve:
...anxiety, sadness or depression, anger, irritability, mental confusion, low sense of self-worth, etc., behavioral symptoms such as phobic avoidance, vigilance, impulsive and compulsive acts, lethargy, etc., cognitive problems such as unpleasant or disturbing thoughts, repetition of thoughts and obsession, habitual fantasizing, negativity and cynicism, etc. Interpersonally, neurosis involves dependency, aggressiveness, perfectionism, schizoid isolation, socio-culturally inappropriate behaviors, etc.6
As an illness, neurosis represents a variety of mental disorders in which emotional distress or unconscious conflict is expressed through various physical, physiological, and mental disturbances, which may include physical symptoms (e.g., hysteria). The definitive symptom is anxieties. Neurotic tendencies are common and may manifest themselves as depression, acute or chronic anxiety, obsessive–compulsive tendencies, specific phobias, such as social phobia, arachnophobia or any number of other phobias, and some personality disorders: paranoid, schizotypal, borderline, histrionic, avoidant, dependent and obsessive–compulsive. It has perhaps been most simply defined as a "poor ability to adapt to one's environment, an inability to change one's life patterns, and the inability to develop a richer, more complex, more satisfying personality."6 Neurosis should not be mistaken for psychosis, which refers to loss of touch with reality, or neuroticism, a fundamental personality trait according to psychological theory.
According to psychoanalytic theory, neuroses may be rooted in ego defense mechanisms, but the two concepts are not synonymous. Defense mechanisms are a normal way of developing and maintaining a consistent sense of self (i.e., an ego), while only those thoughts and behavior patterns that produce difficulties in living should be termed "neuroses".
Carl Jung found his approach particularly fitting for people who are successfully adjusted by normal social standards, but who nevertheless have issues with the meaning of their life.
I have frequently seen people become neurotic when they content themselves with inadequate or wrong answers to the questions of life (Jung,  1989:140).
The majority of my patients consisted not of believers but of those who had lost their faith (Jung,  1989:140).
[Contemporary man] is blind to the fact that, with all his rationality and efficiency, he is possessed by "powers" that are beyond his control. His gods and demons have not disappeared at all; they have merely got new names. They keep him on the run with restlessness, vague apprehensions, psychological complications, an insatiable need for pills, alcohol, tobacco, food – and, above all, a large array of neuroses. (Jung, 1964:82).
Jung found that the unconscious finds expression primarily through an individual's inferior psychological function, whether it is thinking, feeling, sensing, or intuition. The characteristic effects of a neurosis on the dominant and inferior functions are discussed in Psychological Types.
Jung saw collective neuroses in politics: "Our world is, so to speak, dissociated like a neurotic" (Jung, 1964:85).
In essence, neurosis is a distorted way of looking at the world and at oneself, determined by compulsive needs rather than by a genuine interest in the world as it is.
She proposes that it is transmitted to a child from his or her early environment, and that there are a large number of ways this can happen, but:
When summarized, they all boil down to the fact that the people in the environment are too wrapped up in their own neuroses to be able to love the child, or even to conceive of him as the particular individual he is; their attitudes toward him are determined by their own neurotic needs and responses.8
The child's initial reality is then distorted by his or her parents' needs and pretenses. Growing up with neurotic caretakers, the child quickly becomes insecure themselves, developing basic anxiety. To deal with this anxiety, the growing child's own imagination goes to work, creating an idealized self-image:
Each person builds up his personal idealized image from the materials of his own special experiences, his earlier fantasies, his particular needs, and also his given faculties. If it were not for the personal character of the image, he would not attain a feeling of identity and unity. He idealizes, to begin with, his particular "solution" of his basic conflict: compliance becomes goodness, love, saintliness; aggressiveness becomes strength, leadership, heroism, omnipotence; aloofness becomes wisdom, self-sufficiency, independence. What--according to his particular solution--appear as shortcomings or flaws are always dimmed out or retouched.9
Once one identifies with the idealized image, a number of effects follow. One will make claims on others and on life based on the prestige one feels entitled to because of the idealized image. One will impose a rigorous set of standards on oneself in order to attempt to actually measure up to what the idealized image is. One will cultivate pride, and with that will come the vulnerabilities associated with pride that lacks a foundation of real esteem. Finally, one will hate and despise oneself for all one's factual limitations, which keep getting in the way and threatening to pop the bubble. Vicious circles operate to strengthen all of these factors.
Eventually, as one grows to adulthood, one particular "solution" to all the inner conflicts and vulnerabilities will solidify. One will be expansive and will display symptoms of narcissism, perfectionism, or vindictiveness. Or one will be self-effacing, and be compulsively compliant and display symptoms of neediness or codependence. Or one will be resigned, and display schizoid tendencies.
In Horney's view, milder anxiety disorders and full-blown personality disorders all fall under her basic scheme of neurosis as variances in the degree of severity and in the individual dynamics.
The opposite of neurosis is a condition Horney calls self-realization, which is when an individual responds to the world with the full depth of his or her spontaneous feelings rather than just anxiety-driven compulsion, resulting in the person growing to actualize his or her inborn potentialities, in a process Horney compares with an acorn growing into a tree.
- "neurosis" at Dorland's Medical Dictionary
- Russon, John (2003). Human Experience: Philosophy, Neurosis, and the Elements of Everyday Life. State University of New York Press. ISBN 0-7914-5754-0. See also Kirsten Jacobson, (2006), "The Interpersonal Expression of Human Spatiality: A Phenomenological Interpretation of Anorexia Nervosa," Chiasmi International 8, pp. 157-74.
- Horwitz and Wakefield (2007). The Loss of Sadness. Oxford. ISBN 978-0-19-531304-8.
- The American Heritage Medical Dictionary. Houghton Mifflin. 2007. ISBN 978-0-618-82435-9.
- Wilson, Mitchell, (1993), "DSM-III and the Transformation of American Psychiatry: A History". The American Journal of Psychiatry, 150,3, pp. 399-410.
- Boeree, Dr. C. George (2002). "A Bio-Social Theory of Neurosis". Retrieved 2009-04-21.
- Horney, Karen (1950). Neurosis and Human Growth: The Struggle Toward Self-Realization. W. W. Norton & Company, Inc. ISBN 978-0-393-30775-7
- Horney p.18
- Horney p.22
- Angyal, Andras. (1965). Neurosis and treatment: a holistic theory. Edited by E. Hanfmann and R. M. Jones
- Fenichel, Otto. (1945) The Psychoanalytic Theory of Neurosis. New York: Norton Publishing Company.
- Freud, Sigmund. The Standard Edition of the Complete Psychological Works of Sigmund Freud. Trans. James Strachey. 24 vols. London: Hogarth, 1953-74.
- Horney, Karen. Neurosis and Human Growth." Norton, 1950.
- Horney, Karen. Our Inner Conflicts." Norton, 1945.
- Horney, Karen. The Collected Works. (2 Vols.) Norton, 1937.
- Horwitz, A. V. and J. C. Wakefield. The Loss of Sadness: How Psychiatry Transformed Normal Sorrow into Depressive Disorder. Oxford University Press, 2007. ISBN 978-0-19-531304-8.
- Jung, C.G., et al. (1964). Man and his Symbols, New York, N.Y.: Anchor Books, Doubleday. ISBN 0-385-05221-9.
- Jung, C.G. (1966). Two Essays on Analytical Psychology, Collected Works, Volume 7, Princeton, N.J.: Princeton University Press. ISBN 0-691-01782-4.
- Jung, C.G.  (1971). Psychological Types, Collected Works, Volume 6, Princeton, N.J.: Princeton University Press. ISBN 0-691-01813-8.
- Jung, C.G.  (1989). 'Memories, Dreams, Reflections, New York, N.Y.: Vantage Books. ISBN 0-679-72395-1
- Russon, John. (2003). Human Experience: Philosophy, Neurosis, and the Elements of Everyday Life. Albany: State University of New York Press. ISBN 0-7914-5754-0
- Nancy McWilliams (2011). Psychoanalytic Diagnosis, Second Edition: Understanding Personality Structure in the Clinical Process. Guilford Press. ISBN 978-1-60918-494-0.
- Winokur, Jon. Encyclopedia Neurotica. 2005. ISBN 0-312-32501-0.
- LADELL RM, HARGREAVES TH (October 1947). "The Extent of Neurosis". Br Med J 2 (4526): 548–549. doi:10.1136/bmj.2.4526.548. PMC 2055884. PMID 20267012.