Five-year stability of ICD-10 diagnoses among Chinese patients presented with first-episode psychosis in Hong Kong.
BACKGROUND
Diagnostic stability is one measure of predictive validity for psychiatric syndromes. It is an under-studied area in functional psychosis despite its clinical and research implications. We aimed at evaluating the stability of ICD-10 diagnoses in a sample of young people with first-episode psychosis.


METHODS
One hundred and sixty-six Hong Kong Chinese enrolled in a regional first-episode psychosis treatment program were studied. Subjects' baseline and final 5-year consensus diagnoses were established via systematic medical records' review to determine diagnostic stability and to identify predictors of diagnostic shift towards schizophrenia spectrum.


RESULTS
The overall diagnostic consistency was 80.7%. Bipolar affective disorder and schizophrenia were the most stable diagnostic categories over 5 years with prospective consistency of 100% and 95.8% respectively. The least stable baseline diagnoses were unspecified non-organic psychosis, acute and transient psychotic disorders and delusional disorder. Around one-fifth (19.3%) of subjects had diagnostic revision in 5 years. The predominant pattern of diagnostic shift was towards schizophrenia spectrum disorder. Family history of psychosis and longer duration of untreated psychosis were associated with diagnostic transition towards schizophrenia spectrum.


CONCLUSIONS
Schizophrenia and bipolar affective disorder were diagnostically stable and could be reliably classified at intake in a Chinese first-episode psychosis sample using the ICD-10 criteria. Diagnostic instability in the least prevalent categories of functional psychosis highlights the limitations of current taxonomies and calls for ongoing revision of diagnostic criteria. In the absence of biological marker, longitudinal validation across consecutive episodes is necessary for accurate diagnostic ascertainment.
Chang
Wing Chung
WC
Dept of Psychiatry, Tai Po Hospital, Tai Po, New Territories, Hong Kong SAR, China. littlestone_113@yahoo.com
Pang
Shirley Lai Kwan
SL
Chung
Dicky Wai Sau
DW
Chan
Sandra Sau Man
SS
D000293:Adolescent; D044466:Asian People / Q000235:genetics; D001714:Bipolar Disorder / Q000175:diagnosis; D003937:Diagnosis, Differential; D005260:Female; D006723:Hong Kong; D006801:Humans; D038801:International Classification of Diseases; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000145:classification* / Q000175:diagnosis*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012559:Schizophrenia / Q000175:diagnosis; D055815:Young Adult