However, if properly assessed, secondary negative symptoms are amenable to treatment.Scales for specifically assessing the presence of negative symptoms, and for measuring their severity, and their changes have been introduced since the earlier scales such as the PANNS that deals with all types of symptoms. These scales are the Clinical Assessment Interview for Negative Symptoms (CAINS), and the Brief Negative Symptom Scale (BNSS) also known as second-generation scales. In 2020, ten years after its introduction, a cross-cultural study of the use of BNSS found valid and reliable psychometric evidence for the five-domain structure cross-culturally. The BNSS is designed to assess both the presence and severity and change of negative symptoms of the five recognized domains, and the additional item of reduced normal distress. BNSS can register changes in negative symptoms concerning psychosocial and pharmacological intervention trials. BNSS has also been used to study a proposed non-D2 treatment called SEP-363856. Findings supported the favouring of five domains over the two-dimensional proposition. Cognitive symptoms
An estimated 70% of those with schizophrenia have cognitive deficits, and these are most pronounced in early onset and late-onset illness. These are often evident long before the onset of illness in the prodromal stage, and may be present in early adolescence, or childhood. They are a core feature but not considered to be core symptoms, as are positive and negative symptoms. However, their presence and degree of dysfunction is taken as a better indicator of functionality than the presentation of core symptoms.
Schizophrenia was diagnosed far more in the US than in Europe which used the ICD-9 criteria. The US model was criticised for failing to demarcate clearly those people with a mental illness. In 1980 DSM III was published and showed a shift in focus from the clinically based biopsychosocial model to a reason-based medical model. DSM IV brought an increased focus on an evidence-based medical model. Historical treatment
In the 1930s a number of shock procedures which induced seizures (convulsions) or comas were used to treat schizophrenia. Insulin shock involved injecting large doses of insulin to induce comas, which in turn produced hypoglycemia and convulsions. The use of electricity to induce seizures was in use as electroconvulsive therapy (ECT) by 1938.Psychosurgery, including the lobotomy and frontal lobotomy – carried out from the 1930s until the 1970s in the United States, and until the 1980s in France – are recognized as a human rights abuse. In the mid-1950s the first typical antipsychotic, chlorpromazine, was introduced, followed in the 1970s by the first atypical antipsychotic, clozapine. Political abuse
From the 1960s until 1989, psychiatrists in the USSR and Eastern Bloc diagnosed thousands of people with sluggish schizophrenia, without signs of psychosis, based on "the assumption that symptoms would later appear". Now discredited, the diagnosis provided a convenient way to confine political dissidents. Society and culture
In 2002, the term for schizophrenia in Japan was changed from seishin-bunretsu-byō (精神分裂病, lit. mind-split disease) to tōgō-shitchō-shō (統合失調症, lit. integration–dysregulation syndrome) to reduce stigma.