Kurt Schneider

Schneider coined the terms endogenous depression, derived from Emil Kraepelin's use of the adjective to mean biological in origin, and reactive depression, more usually seen in outpatients, in 1920.[10]

Like Karl Jaspers, Schneider particularly championed diagnoses based on the form, rather than the content of a sign or symptom. For example, he argued that a delusion should not be diagnosed by the content of the belief, but by the way in which a belief is held.

He was also concerned with differentiating schizophrenia from other forms of psychosis, by listing the psychotic symptoms that are particularly characteristic of schizophrenia. These have become known as Schneiderian First-Rank Symptoms or simply, first-rank symptoms.[11]

• Auditory hallucinations.
  • Auditory hallucinations taking the form of a voice or voices repeating the subject's thoughts out loud.
  • Auditory hallucinations discussing the subject or arguing about them and referring to them in the third person.
  • Auditory hallucinations discussing the patient's thoughts as or before they occur.
  • Auditory hallucinations taking the form of a commentary on the subject's thoughts or behavior.
• The experience of intrusion of unusual ideas or thoughts into the subject's mind as a result of the action of some external agency (Thought insertion).
• The experience that the subject's thinking is no longer confined within their own mind but is shared by or is accessible to other people (Thought broadcasting).
• The experience of being deprived of thought as a result of the removal of the subject's thoughts from the mind by some person or influence (Thought withdrawal).
• The experience that actions, sensations, bodily movements, emotions or thought processes are generated by an outside agency that takes over the will of the subject (Passivity experiences).
• Primary delusions: beliefs arising suddenly ‘out of a clear blue sky’ from a normal perception which would seem commonplace and unrelated to others but which nevertheless generates an unshakable delusional conviction.[12]
• Delusional perception - the belief that a normal perception has special significance or meaning.[13]

The reliability of using first-rank symptoms for the diagnosis of schizophrenia has since been questioned,[14] although the terms might still be used descriptively by mental health professionals who do not use them as diagnostic aids.

Individuals with dissociative identity disorder may experience first-rank symptoms more commonly than even patients with schizophrenia[15] though patients with DID lack the negative symptoms of schizophrenia and normally do not mistake hallucinations for reality.[16] Differentiating between dissociative identity disorder and psychotic disorders is not done by listing first-rank symptoms as these conditions have a considerable overlap yet a different overall clinical picture and treatment approach.[17]

Schneider also played a key role in developing concepts of psychopathy, used in a broad sense to mean personality disorder or particularly the connotation of Gemütlose psychopathy with antisocial personality disorder. He published the influential 'The Psychopathic Personalities' in 1923. This was based in part on his earlier 1921 work 'The Personality and Fate of Registered Prostitutes' where he outlined 12 character types.

Schneider sought to put psychopathy diagnoses on a morally neutral and scientific footing. He defined abnormal personality as a statistical deviation from the norm, vaguely conceptualised. He thought very creative or intelligent people had abnormal personalities by definition, but defined the psychopathic personality as those who suffered from their abnormal personality or caused suffering to society because of it. He did not see these as mental illnesses as such - thus adding to a divide, contrary to Eugen Bleuler for example, between those considered psychotic and those considered psychopathic.

Schneider's unsystematic typology was based on his clinical views. He proposed 10 psychopathic personalities: those showing abnormal mood/activity; the insecure sensitive and insecure anankastic (drifting, feckless); fanatics; self-assertive; emotionally unstable; explosive; Gemütlose; Haltlose and asthenic.

Schneider's work in this respect is said to have influenced all future descriptive typologies, including the current classifications of personality disorders in the DSM-V and ICD-10. Nevertheless, Schneider is considered to not exactly have succeeded in his attempted and claimed production of a value-free non-judgmental diagnostic system.[18] In fact, Schneider's mixing of the medical and the moral has been described as the most noteworthy aspect of this work, which has been linked back to German reception of Cesare Lombroso's theory of the 'born criminal', redefined by Emil Kraepelin and others (see also Koch) in to psychiatric terms as a 'moral defect'. After World War I it lived on in Schneider's 'gemütlos' (compassionless) psychopaths, or what Karl Birnbaum called 'amoral' psychopaths. It has been described as remarkable that Schneider criticized Kraepelin and others for basing their personality diagnoses on moral judgments, yet appeared to do so himself. For example, Schneider admitted that the 'suffering of society' was a 'totally subjective' and 'teleological’ criterion for defining psychopathic personalities, but said that in 'scientific studies' this could be avoided by operating by the broader statistical category of abnormal personalities, which he believed were always congenital and therefore largely hereditary. The attempt to finesse the problem of value judgments has been described as 'clearly unsatisfactory'.[19]