SCHIZOPHRENIA SPECTRUM DISORDERS IN CHILDREN AND ADOLESCENTS: PREVALENCE AND DIAGNOSTICS

The significance of studying the prevalence, age- and sex-related differences and diagnostic aspects of schizophrenia spectrum disorders (F2 Schizophrenia, schizotypal and delusional disorders) in pediatric and adolescent patients of mental health facilities is linked to the upcoming release of the International Classification of Diseases, Revision 11 (ICD-11). Its whole chapters have been updated, including disorders in the schizophrenia group. Diagnostic challenges posed by this debilitating group of mental disorders are associated with the diversity of clinical presentations, the incompleteness of psychopathological phenomena syndromes, and vague atypical symptoms. Changes in the prevalence of these disorders identified by the analysis of medical records at a mental health facility for children (a decline in the number of patients with F20, schizophrenia, and a surge in the number of patients with F21, schizotypal disorder) and significant disagreement about and disagreement about the diagnostic criteria for schizophrenia spectrum disorders in children and adolescents, evaluation of their dynamics, outcomes, and the social functioning of the patient necessitate further prospective follow-up studies aimed at overcoming the identified difficulties in the diagnosis, treatment and rehabilitation of such patients.

ВЕСТНИК РГМУ 3, 2021 VESTNIKRGMU.RU | |  Other schizophrenia spectrum disorders (n = 32) Other schizophrenia spectrum disorders (n = 2) Other schizophrenia spectrum disorders (n = 2) the dimensional principle [6,7]. Timely diagnosis is no less important than an accurate definition. Multiple foreign and some Russian publications provide evidence that early treatment at the prodromal stage can significantly reduce the risk of the first psychotic episode, improve the long-term outcome, maintain social drive and the high level of the patient's functioning [8][9][10]. These data underscore the importance of further research into the prevalence, diagnostic challenges and treatment of schizophrenia spectrum disorders. Recent epidemiological data on schizophrenia spectrum disorders among children and adolescents are very scarce.
There are a few publications on the prevalence of the major mental disorders, including schizophrenia spectrum disorders, among children and adolescents in the past 15 years [11,12].
The analysis of medical records of patients undergoing medical examination and treatment at G. E. Sukhareva Research and Practical Center for Mental Health of Children and Adolescents in 1999-2019 allowed us to identify the main diagnostic challenges and problems of studying the prevalence of schizophrenia and schizophrenia spectrum disorders (F2) in children and adolescents since the adoption of ICD-10 in Russia. Throughout the specified period, the prevalence of F2 disorders remained stable (± standard deviation, SD) at 10.12 ± 1.61. There was an insignificant increase in prevalence (both in relative and absolute values) during the past two years included in the analysis, which coincided with a rise in hospitalizations and probably reflected a growing trend in the prevalence of mental illness in children and adolescents. Fig. 1 shows cumulative data for the entire analyzed period and data for the first and last years of our study. The following schizophrenia spectrum disorders prevailed among children and adolescents: schizophrenia (F20), schizotypal disorder (F21), acute and transient psychotic disorders (F23), and schizoaffective disorder (F25). Together, these conditions accounted for 99.6% of all mental illnesses in the studied cohort and formed the core of the spectrum.

Prevalence of schizophrenia spectrum disorders
Of all the patients with F2, 48.8% had schizophrenia, about one-third (32.3%) had schizotypal disorder, 11.7% had schizoaffective disorder, and 6.8% had transient psychotic disorder. Importantly, when ICD-10 was first introduced in 1999, schizophrenic patients made up 75.3% of all F2 patients. By 2019, the proportion of schizophrenic patients had decreased 3-fold, accounting for 25.8% of patients in the F2 group. By contrast, the number of patients diagnosed with schizotypal disorder had increased dramatically (6-fold percentagewise and 19-fold in absolute values). The number of patients with schizoaffective disorder had increased almost 2.5-fold percentagewise and 7.8-fold in absolute values. The prevalence of transient psychotic disorders was the most stable.
The majority of the patients were 11-14 years old, except for the patients with schizoaffective disorder, who were 15-17 years old. Male patients dominated the group of patients with schizophrenia, schizotypal and schizoaffective disorders. Sex differences were minimal in the group of patients with transient psychosis: 53.1% were males and 46.9% were females.
Prevalence dynamics of schizophrenia and schizophrenia spectrum disorders over analyzed period

Trends in prevalence and diagnostic problems associated with schizophrenia spectrum disorders in children and adolescents
The analysis revealed a few trends in the prevalence of schizophrenia spectrum disorders (F2 according to ICD-10) and some problems associated with their diagnosis in children and adolescents. The most salient problem persisting over the last 3 years covered by the analysis was a diagnostic imbalance: a decline in the number of patients with schizophrenia (F20) and a surge in the number of patients with schizotypal disorder (F21). Of all the young inpatients of the Center, 32.2% had F21. In this subgroup, 71.2% were diagnosed with F21.8 schizotypal personality disorder, 6.3% were diagnosed with F21.3 pseudoneurotic schizophrenia, and 15.2% were diagnosed with F21.4 pseudopsychopathic schizophrenia.
In our opinion, the term "schizotypal personality disorder" (F21.8) is incorrect because personality disorder cannot be diagnosed in children and adolescents; but it is legitimate to say that their schizoid traits are progressing. The criteria for BULLETIN OF RSMU 3, 2021 VESTNIKRGMU.RU | | Fig. 2. Prevalence dynamics of schizophrenia and major schizophrenia spectrum disorders relative to the total number of hospitalized patients the diagnosis of schizotypal personality disorder in children and adolescents do not include character traits; instead, they are based on the symptoms specified in the preamble of the Russian Thesaurus of Psychiatry, which is used to classify mental disorders. The preliminary analysis of medical records revealed that the reported clinical presentations did not meet the criteria for schizotypal disorder in many cases; however, in all age groups the number of patients diagnosed with schizotypal personality disorder (F21.8) increased at discharge. In our opinion, this diagnostic transformation can be explained by social factors and stigma, which significantly affect clinical decision-making and force the clinician to come up with a diagnosis that would allow the patient to integrate into society. The stigma of schizophrenia has been widely discussed in Russian and foreign publications [14,15]. Patients and their parents fear being stigmatized. This fear is not irrational because a grave psychiatric diagnosis can reduce career opportunities and chances to marry. Due to fear, patients delay a visit to public or private psychiatrists, psychologists, neurologists, etc. This prevents them from receiving timely health care, which, among other things, includes social and pedagogical interventions, psychotherapy and other types of rehabilitation.

Conclusion
The main candidate explanations of the identified diagnostics problems are a) changes in the clinical presentation of the disease, such as the growing prevalence of non-psychotic forms of schizophrenia spectrum disorders, including attenuated and quasi-psychosis (this is partly supported by the relatively stable number of patients with transient psychosis (F23) and schizoaffective disorder (F25)); b) vague yet diverse symptoms at the prodromal stage before the onset of psychotic symptoms in children and teenagers, a dissociation between the severity of the condition and social functioning, insufficient clarity of diagnostic criteria; c) the stigma of schizophrenia and the tendency to mitigate it be establishing a more socially acceptable diagnosis. The identified difficulties and disagreement about the diagnostic criteria for schizophrenia spectrum disorders in children and adolescents, evaluation of their dynamics, outcomes, and the social functioning of the patient necessitate further prospective follow-up studies.