Skip to content

Ganser Syndrome Case Study

Synonyms: prison psychosis, pseudodementia, hysterical pseudodementia

This is a rare condition of uncertain or variable aetiology. It was first described by the psychiatrist Sigbert Ganser in 1898. Ganser described the syndrome after studying the behaviour of three inmates of a prison and thus it has acquired the synonym 'prison psychosis'. He was of the opinion that the condition was hysterical or malingering in origin.

It is thought that people develop Ganser's syndrome, either consciously or unconsciously, to avoid an unpleasant situation. There has been much debate over the years as to whether it is psychotic, hysterical or factitious in origin. Association with serious illness may suggest an aetiology similar to delirium. It is fairly common to find it associated with head injury. There may be no one cause in all cases.

The International Classification of Diseases (ICD-10) classifies Ganser's syndrome as a dissociative disorder.[1]It is often classified as a factitious disorder.


Ganser's syndrome is said to be very rare with fewer than 100 cases in the literature.[2]The precise incidence is not known, as most of the recorded cases in the literature describe only individual patients and criteria are lax. Ganser's syndrome is more common in men, with a probable male-to-female ratio of 3 or 4:1. It is most frequently described in individuals between the ages of 15 and 40 but a wide range of ages has been reported. It has been described in children.[3]Ganser's syndrome is thought to be precipitated by episodes of severe stress but has also been described in association with head injury.


The condition tends to occur against a background of head injury or serious illness. Severe psychosocial stress can also be a cause; psychosocial stresses accompanying immigration may have a catalytic effect in triggering the condition.[4] The four principal features are:

  • Approximate answers.
  • Clouding of consciousness.
  • Somatic conversion symptoms such as hysterical paralysis.
  • Hallucinations, visual or auditory.

The term approximate answers needs explanation. It is the most characteristic feature of the condition and German terms such as vorbeireden meaning talking past and vorbeigehen meaning to pass by or danebenreden meaning talking next to are used in the literature. The essential feature of approximate answers is that whilst the patient gives an incorrect response, the nature of the response suggests that he/she understands the question. Thus the patient may say that grass is blue and that a dog has three legs. When asked the day of the week or month of the year, he/she will give a day of the week or month of the year but the wrong one. This is in direct contrast to answers that are simply nonsensical, perseverative or otherwise inappropriate.

Diagnostic criteria are not well established. Most authorities would want approximate answers and at least one other principal feature to make the diagnosis.

Other features include:

  • A dreamy or perplexed appearance.
  • Memory or personal identity loss.
  • No recollection of the condition upon recovery.
  • Perseveration.
  • Echolalia.
  • Echopraxia.
  • Confusion.
  • Precipitating stress.
  • Loss of personal identity.

There is no typical finding on examination. A full neurological examination should be performed and a mental state examination. There are now more sophisticated tests to assess exaggerated or fabricated cognitive dysfunction.[5] Look for signs of self-inflicted injury.

Differential diagnosis[2]

Associated diseases[2]

Ganser's syndrome has been reported in the following:

  • Neurosyphilis
  • Epilepsy
  • Post-stroke
  • Meningiomas
  • Post-anoxia
  • Postpartum psychosis
  • Traumatic brain injuries
  • Infections
  • Various dementias


No investigation is diagnostic but a number may be performed to exclude other pathology. It is important to exclude an underlying organic cause.

  • Mental state examination should be performed.
  • FBC.
  • U&Es.
  • LFTs.
  • Vitamin B12 levels.
  • TFTs.
  • Urine drug screen
  • CT scan or MRI scan to exclude structural pathology.
  • Lumbar puncture may be performed to exclude meningitis or encephalitis.
  • Electroencephalograph (EEG) does not usually show any specific disorder.[6]However, it should be performed to rule out underlying causes such as delirium or seizure disorder.

One study reported that a man pursuing an insurance claim presented with Ganser's syndrome-like symptoms. Simple memory tests and the existence of symptoms not typical of the syndrome were used to exclude the syndrome.[7]


Admission to a psychiatric unit in the acute phase is usually required for assessment and to prevent harm to self or to others. Simple psychotherapy is the mainstay of treatment. Drug therapy is of limited value and not usually required. Evidence of benefit from benzodiazepines, antipsychotic medication or other treatments, such as electroconvulsive therapy or hypnosis, is very limited.


If the precipitating stress has been withdrawn, symptoms usually resolve spontaneously within days but there is usually no recollection of the illness. Sometimes severe depression follows.

Mortality and morbidity are related to the underlying cause, especially if organic.

  1. 2015/16 ICD-10 diagnostic code F44.89 - other dissociative and conversion disorders; ICD10

  2. Dwyer J, Reid S; Ganser's syndrome. Lancet. 2004 Jul 31-Aug 6364(9432):471-3.

  3. Spodenkiewicz M, Taieb O, Speranza M, et al; Case report of Ganser syndrome in a 14-year-old girl: another face of depressive disorder? Child Adolesc Psychiatry Ment Health. 2012 Feb 16(1):6. doi: 10.1186/1753-2000-6-6.

  4. Staniloiu A, Bender A, Smolewska K, et al; Ganser syndrome with work-related onset in a patient with a background of Cogn Neuropsychiatry. 2009 May14(3):180-98.

  5. Wisdom NM, Callahan JL, Shaw TG; Diagnostic utility of the structured inventory of malingered symptomatology to detect malingering in a forensic sample. Arch Clin Neuropsychol. 2010 Mar25(2):118-25. Epub 2010 Jan 28.

  6. Boutros NN, Struve F; Electrophysiological assessment of neuropsychiatric disorders. Semin Clin Neuropsychiatry. 2002 Jan7(1):30-41.

  7. Merckelbach H, Peters M, Jelicic M, et al; Detecting malingering of Ganser-like symptoms with tests: a case study. Psychiatry Clin Neurosci. 2006 Oct60(5):636-8.

Ganser syndrome is a rare dissociative disorder previously classified as a factitious disorder. It is characterized by nonsensical or wrong answers to questions or doing things incorrectly, other dissociative symptoms such as fugue, amnesia or conversion disorder, often with visual pseudohallucinations and a decreased state of consciousness. It is also sometimes called nonsense syndrome, balderdash syndrome, syndrome of approximate answers, hysterical pseudodementia or prison psychosis. This last name, prison psychosis, is sometimes used because the syndrome occurs most frequently in prison inmates, where it may be seen as 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, but 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 'Three'.

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.[1]


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.[2]

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 last view more towards the first.[citation needed]

Ganser syndrome is currently classified under dissociative disorders, to which it moved in the DSM IV from the factitious disorders.


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)."[3]

Diagnosing Ganser syndrome is very challenging, because some measure of dishonesty is involved and 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." 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.[4]


The disorder is extraordinarily rare. While individuals of all 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 to 62 years old. It has been reported in children.[5]

The disorder is apparently most common in men and prisoners, although prevalence data and familial patterns are not established.[6]


It is named for Sigbert Ganser, who characterized it in 1898.[7][8]

See also[edit]


  1. ^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. doi:10.2190/NAQ6-T7PJ-KA0W-JLFG. PMID 3522461. 
  2. ^AJ Giannini, HR Black. Psychiatric, Psychogenic and Somatopsychic Disorders Handbook. Garden City, NY. Medical Examination Puclishing Co. Pg. 136. ISBN 0-87488-596-5.
  3. ^American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Text rev. Washington, DC. American Psychiatric Association, 2000.
  4. ^Carney MW, Chary TK, Robotis P, Childs A (1987). "Ganser syndrome and its management". The British Journal of Psychiatry. 151 (5): 697–700. doi:10.1192/bjp.151.6.597. PMID 3446318. 
  5. ^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. doi:10.1097/00004583-199701000-00024. PMID 9000788. 
  6. ^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. 
  7. ^synd/1351 at Who Named It?
  8. ^S. J. M. Ganser. Über einen eigenartigen hysterischen Dämmerzustand. Archiv für Psychiatrie und Nervenkrankheiten, Berlin, 1898, 30: 633-640.

Further reading[edit]