Early-onset schizophrenia: studying the links between cognitive and clinical dimensions.

BACKGROUND: Early-onset schizophrenia (EOS), a rare and severe chronic psychiatric condition, is defined by an onset of schizophrenia symptoms before the age of 18. Core symptoms also include cognitive impairments. However, little is known about links between psychiatric symptoms of EOS and cognitive abilities. OBJECTIVE: To explore the clinical and neurocognitive profiles of EOS patients and their links. METHOD: EOS patients have been phenotyped using standardised psychiatric assessments for DSM-5 diagnoses (K-SADS-PL) and for symptoms (PANSS and SANS), together with neurocognitive evaluations. RESULTS: The EOS sample (n = 27, 12.4 +/-3.2 years) presented hallucinations (83%), negative symptoms (70%) and delusion (59%). 81% of patients presented comorbidities such as anxiety disorders (33%), autism spectrum disorder (26%) and attention-deficit hyperactivity disorder (26%). Patients presented borderline intellectual deficiency (total IQ = 72.5 +/-4.7), with low performances in working memory subtest. We highlight a positive correlation between the IQ and intensity of positive symptoms (PANSS) and between the IQ and a first treatment being administered at an older age. We also highlight a negative correlation between the IQ and attention items of SANS. CONCLUSION: Cognitive skills are correlated with symptom intensity in EOS patients. An older age of onset seems to be a protective factor for cognitive development.

Early-Onset Schizophrenia in a paediatric population of French psychiatric and medico-social care centres: A cross sectional study.

BACKGROUND: Early-Onset Schizophrenia (EOS) is rare but severe mental health disorder in children and adolescents. Diagnosis of schizophrenia before the age of 18 years remains complex and challenging, especially in young children. In France, there are no recent reliable epidemiological data about the prevalence of EOS. The present study evaluates the EOS rate in a target clinical population of children and adolescents in psychiatric and medico-social care centres in the South-East of France. METHODS: Psychiatric and medico-social centres for children and adolescent in the geographical area have been contacted, and after receiving their agreement to participate in the study, eligible patients corresponding to inclusion criteria were selected based on patients' medical records. Main inclusion criteria were age 7 to 17 years and intelligence quotient > 35. EOS categorical diagnosis was assessed by Kiddie-SADS Present and Lifetime psychosis section. RESULTS: 37 centres participated and 302 subjects have been included in the study. The main result was the categorical diagnosis of EOS in 27 subjects, corresponding to a rate of 8.9% in the study population. Half of the patients presented mild to moderate intellectual deficiency. Interestingly, only 2.3% had a diagnosis of schizophrenia spectrum disorder noted in their medical records before standardized assessment. CONCLUSIONS: The results of the study highlight the importance of using a standardized diagnostic tool for the diagnosis of schizophrenia in the paediatric population. In fact, EOS might be underdiagnosed in children and adolescents with neurodevelopmental disorders and subnormal cognitive functioning. TRIAL REGISTRATION: NCT01512641. Registered 19 January 2012; https://clinicaltrials.gov/ct2/show/NCT01512641.