The ICD-10 and DSM-IV do not specify any diagnostic criteria—apart from approximate answers—as a requirement for a Ganser syndrome diagnosis. Most case studies of the syndrome also depend on the presence of approximate answers and at least one of the other symptoms described by Ganser in his original paper. Usually when giving wrong answers, individuals 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. Amnesia, loss of personal identity, and clouding of consciousness were among the most common symptoms apart from approximate answers.Although there is currently no uniform way to diagnose the syndrome, a full neurological and mental state examination is recommended to determine its presence as well as tests that assess malingering. In addition to mental examination, other investigations should be done to exclude other underlying causes. These include computer tomography scans (CT) or magnetic resonance imaging (MRI) scans to exclude structural pathology, lumbar puncture to exclude meningitis or encephalitis, and electroencephalography (EEG), to exclude delirium or seizure disorder.Diagnosing Ganser syndrome is challenging because of its rarity and symptom variability. The manifested symptoms may be dependent on the individuals conception of what mental illness entails, creating the possibility of a wide range of combinations of symptoms present in an individual with Ganser syndrome.
Ganser syndrome is a rare dissociative disorder characterized by nonsensical or wrong answers to questions and other dissociative symptoms such as fugue, amnesia or conversion disorder, often with visual pseudohallucinations and a decreased state of consciousness. The syndrome has also been called nonsense syndrome, balderdash syndrome, syndrome of approximate answers, hysterical pseudodementia or prison psychosis. The term 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. Psychological symptoms generally resemble the patients sense of mental illness rather than any recognized category. The syndrome may occur in persons with other mental disorders such as schizophrenia, depressive disorders, toxic states, paresis, alcohol use disorders and factitious disorders. Ganser syndrome can sometimes be diagnosed as merely malingering, but it is more often defined as dissociative disorder.The identification of Ganser syndrome is attributed to German psychiatrist Sigbert Ganser (1853–1931). In 1898, he described the disorder in prisoners awaiting trial in a penal institution in Halle, Germany. He named impaired consciousness and distorted communication, namely in the form of approximate answers (also referred to as Vorbeireden in the literature), as the defining symptoms of the syndrome. Vorbeireden involves the inability to answer questions precisely, although the content of the questions is understood.Ganser syndrome is described as a dissociative disorder not otherwise specified (NOS) in the DSM-IV, and is not currently listed in the DSM-5. It is a rare and an often overlooked clinical phenomenon.