11 - Earlier diagnostic criteria

Earlier diagnostic criteria

© SPMM Course 4. Classification of psychosis Schizophrenia Schizophrenia usually manifests as a severe psychotic illness with onset in early childhood, characterised by bizarre (i.e. Schneiderian) delusions, auditory hallucinations, thought disorder, strange behaviour and progressive deterioration in personal, domestic, social and occupational functioning, all occurring in clear consciousness. Common symptoms: The International Pilot Study of Schizophrenia survey determined the commonest symptoms exhibited by 306 acute schizophrenia patients in 9 countries as follows: Lack of insight – 97% Auditory hallucinations - 74% Ideas of reference – 70% Suspiciousness – 66% Flatness of affect – 66% Second person hallucinations – 65% Delusional mood – 64% Delusions of persecution – 64% Thought alienation – 52% Echo De Pensee, Gedankenlautwerden- 50% Earlier diagnostic criteria Before DSM-IV and ICD-10, various criteria were put forward to diagnose schizophrenia. Some of these are MRCPsych favourites: St Louis or Feighner criteria (Feighner et al. 1972) or Washington University Criteria National Institute of Mental Health (NIMH) Research Diagnostic Criteria (RDC) predating DSM-III For a diagnosis of schizophrenia, A through C are required: A. Both of the following are necessary: o A chronic illness with at least six months of symptoms prior to the index evaluation without a return to the premorbid level of psychosocial adjustment. o The absence of a period of depressive or manic symptoms sufficient to qualify for affective disorder or probable affective disorder. B. The patient must have at least one of the following: o Delusions or hallucinations without significant perplexity or disorientation associated with them. o Verbal production that makes communication difficult because of a lack of logical or understandable organization. (In the presence of muteness the diagnostic decision must be deferred.) C. At least three of the following manifestations must be present for a diagnosis of "definite" schizophrenia, and two for a diagnosis of "probable" schizophrenia. o Single o Poor premorbid social adjustment or work history o Family history of schizophrenia o Absence of alcoholism or drug abuse within one year Includes a polythetic symptom criterion, a duration criterion and an exclusion criterion.

The symptom criterion lists eight symptoms or groups of symptoms. The first seven symptom groups are Schneiderian first-rank symptoms and other delusions or hallucinations, the last one gives diagnostic value to formal thought disorder if accompanied by either blunted or inappropriate affect, delusions or hallucinations of any type or grossly disorganized behaviour.

The duration criterion requires that signs of the illness have lasted at least 2 weeks from the onset of a noticeable change in the  subject’s  usual  condition.

The exclusion criterion describes the differential diagnosis with affective disorders: at no time during the active period of illness being considered did the subject meet the full criteria for either probable or definite manic or depressive syndrome to such a degree that it was a prominent part of the illness.