Abstract Body

Several changes to the classification of schizophrenia and other psychotic disorders have been made to increase the reliability, clinical use and validity of the diagnostic classification which are considered here.

A diagnosis of schizoaffective disorder would only be made in ICD-11 when the definitional requirement of schizophrenia is met concurrently with mood symptoms that meet the definitional requirements of a moderate or severe depressive episode, a manic episode, or a mixed episode. This requirement is more restrictive compared to ICD-10, which just required the presence of symptoms of schizophrenia and mood disorder. The total duration requirement would be 4 weeks.

A cross-sectional approach was maintained in the ICD-11 for schizoaffective disorders as there is no evidence on how a longitudinal “lifetime” criterion impacts cross-sectional inter-rater reliability, and the reliability of lifetime symptoms' report by patients and retrospective assessment by clinicians remains unknown.

Abstract Body

There is a considerable overlap of psychotic and mood symptoms in patients with severe mental disorders, and a large proportion of patients meeting diagnostic criteria experience significant mood symptoms. The diagnosis of schizophrenia – schizoaffective type /schizoaffective disorder has been a part of the Diagnostic and statistical manual since the DSM-I. Even if the need for a diagnosis capturing this particular clinical picture obviously is needed, the agreement about when to use the diagnosis of schizoaffective disorder as well as the diagnostic reliability is low. There is an agreement that the diagnosis covers episodes with an overlap between a psychotic episode meeting the A criteria for schizophrenia and a major mood episode where the psychotic symptoms continue after the end of the mood symptoms. Given the prevalence of depression in schizophrenia, some episodes, however, meet the criteria for schizoaffective disorders while others do not. The DSM-5 thus argues that the pattern of overlapping symptoms should be present in the majority of episodes. Keeping the cross-sectional approach favoured by previous versions of the DSM and the ICD will here continue to spread diagnostic confusion.