Simple-type schizophrenia is a sub-type of schizophrenia included in the International Classification of Diseases (ICD-10),[1] in which it is classified as a mental and behaviour disorder.[2] It is not included in the current Diagnostic and Statistical Manual of Mental Disorders (DSM-5) or the ICD-11.[3][4] Simple-type schizophrenia is characterized by negative ("deficit") symptoms, such as avolition, apathy, anhedonia, reduced affect display, lack of initiative, lack of motivation, low activity; with absence of hallucinations or delusions of any kind.

Simple schizophrenia was included as a proposed diagnosis for further study in the appendix of the former DSM-IV.[5]

Signs and symptoms

It has possibly the earliest onset compared to all other schizophrenias, considered to begin in some within childhood. Symptoms of schizophrenia simplex include an absence of will, impoverished thinking and flattening of affect. There is a gradual deterioration of functioning with increased amotivation and reduced socialization.[6][7] It is considered to be rarely diagnosed and is a schizophrenia without psychotic symptoms.[8]

In a study of patients in a Massachusetts hospital, persons with simple schizophrenia were found to make attempts at reality fulfillment with respect to the more primitive needs; tending toward the achievement of fulfillment of these needs rather than engaging in fantasy as is typically found as a reaction to environmental stimuli by the psychotic person.[9]

Causes

A progressive state of simple schizophrenia results often in cases of adolescent onset juvenile general paresis. Paresis is caused by placental-foetal transfer of infection and results in intellectual (mental) subnormality. Occurrence of this type of paresis is altogether uncommon (Lishman 1998).[10]

Diagnosis

Classification

ICD

The WHO first listed the condition in the 6th revision of the International Classification of Diseases ICD-6 (1949) and it stayed in the manual until ICD-10.[11]

ICD-9

The ICD-9 simple-type schizophrenia description: