Schizophrenia Spectrum Disorders: A Review

Schizophrenia spectrum disorders are schizophrenia-like disorders which are not fulfilling the diagnostic criteria for schizophrenia but which are sharing symptoms, causes and risk factors with schizophrenia. The concept emerges from the recognition that the clinical syndrome of schizophrenia is too restrictive to tap the whole variation of symptoms and features induced by causes underlying schizophrenia. The specific criterion for schizophrenia spectrum disorders is that they are aetiologically related to schizophrenia; and particularly that they are driven by the same familial–genetic factors. Along this line, two types of syndromes were proposed as components of the schizophrenic spectrum: (a) personality features and disorders – sometimes the spectrum concept is restricted to personality traits, and (b) psychotic symptoms and disorders, often with an episodic course, which are sharing clinical features with chronic schizophrenia without meeting the full diagnosis.