Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Ganser syndrome is a rare dissociative disorder previously classified as a factitious disorder. It is characterized by the individual mimicking behavior they think is typical of a psychosis; usually by providing nonsensical or wrong answers to questions, and doing things incorrectly. It is also sometimes called nonsense syndrome, balderdash syndrome, syndrome of approximate answers, pseudodementia or prison psychosis. This last name, prison psychosis, is sometimes used because the syndrome occurs most frequently in prison inmates, where it may represent an attempt to gain leniency from prison or court officials.
Ganser is an extremely rare variation of dissociative disorder. It is a reaction to extreme stress and the patient thereby suffers from approximation or giving absurd answers to simple questions. The syndrome can sometimes be diagnosed as merely malingering, however, it is more often defined as dissociative disorder.
Symptoms include a clouding of consciousness, somatic conversion symptoms, confusion, stress, loss of personal identity, echolalia, and echopraxia. The psychological symptoms generally resemble the patient's sense of mental illness rather than any recognized category. Individuals also give approximate answers to simple questions. For example, "How many legs are on a cat?", to which the subject may respond '3'.
The syndrome may occur in persons with other mental disorders such as schizophrenia, depressive disorders, toxic states, paresis, alcohol use disorders and factitious disorders. EEG data does not suggest any specific organic cause.
The original description by Sigbert Josef Maria Ganser in 1898 pointed out their hysterical twilight state. They may also describe hallucinations which are usually more florid than those in schizophrenia. They may also have disorders of sensation similar to those in conversion disorder. They may be inattentive or drowsy.
Some workers believe there is a genuine psychosis underlying this, others believe it is a dissociative disorder, while still others believe it is the result of malingering. Over the years, opinions have seemed to move from the first view more towards the last.
According to the DSM-IV-TR, which classifies Ganser syndrome as a dissociative disorder, it is the giving of approximate answers to questions (e.g. "2 plus 2 equals 5" when not associated with dissociative amnesia or dissociative fugue.
Diagnosing Ganser syndrome is very challenging, not only because some measure of dishonesty is involved but also because it is very rare.
Usually when giving wrong answers they are only slightly off showing that the individual understood the question. For instance, when asked how many legs a horse has they might say, "five." Also, although subjects appear confused in their answers, in other respects they appear to understand their surroundings.
Hospitalization may be necessary during the acute phase of symptoms, and psychiatric care if the patient is a danger to self or others. A neurological consult is advised to rule out any organic cause. 
The disorder is extraordinarily rare with less than 100 recorded cases. While individuals of all racial backgrounds have been reported with the disorder, there is a higher inclination towards males (75% or more). The average age of those with Ganser syndrome is 32 and it stretches from ages 15-62 years old. It has been reported in children.
The disorder is apparently most common in men and prisoners although prevalence data and familial patterns are not established.
It is named for Sigbert Ganser, who characterized it in 1898.
- ↑ Cocores JA, Schlesinger LB, Gold MS (1986). "A review of the EEG literature on Ganser's syndrome". International journal of psychiatry in medicine. 16 (1): 59–65. PMID 3522461.
- ↑ American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Text rev. Washington, DC American Psychiatric Association, 2000.
- ↑ Carney MW, Chary TK, Robotis P, Childs A (1987). "Ganser syndrome and its management". The British journal of psychiatry : the journal of mental science. 151: 697–700. PMID 3446318.
- ↑ Miller P, Bramble D, Buxton N (1997). "Case study: Ganser syndrome in children and adolescents". Journal of the American Academy of Child and Adolescent Psychiatry. 36 (1): 112–5. PMID 9000788.
- ↑ Brugha T, Singleton N, Meltzer H; et al. (2005). "Psychosis in the community and in prisons: a report from the British National Survey of psychiatric morbidity". The American journal of psychiatry. 162 (4): 774–80. doi:10.1176/appi.ajp.162.4.774. PMID 15800152.
- ↑ Template:WhoNamedIt
- ↑ S. J. M. Ganser. Über einen eigenartigen hysterischen Dämmerzustand. Archiv für Psychiatrie und Nervenkrankheiten, Berlin, 1898, 30: 633-640.
de:Ganser-Syndrom nl:Syndroom van Ganser fi:Ganserin oireyhtymä