Evolution of first episode psychosis diagnoses and health service use among young Maori and non-Maori-A New Zealand national cohort study

Aims The validity of diagnostic classification in early psychosis has important implications for early intervention; however, it is unknown if previously found disparities between Maori (Indigenous people of New Zealand) and non-Maori in first episode diagnoses persist over time, or how these differences impact service use. Methods We used anonymized routine mental health service data and a previously established cohort of over 2400 13-25-year-old youth diagnosed with FEP between 2009 and 2012, to explore differences in diagnostic stability of psychosis diagnoses, comorbid (non-psychosis) diagnoses, and mental health service contacts between Maori and non-Maori in the five-year period following diagnosis. Results Differences in schizophrenia and affective psychosis diagnoses between Maori and non-Maori were maintained in the five-year period, with Maori being more likely to be diagnosed with schizophrenia (51% vs. 35%), and non-Maori with bipolar disorder (28% vs. 18%). Stability of diagnosis was similar (schizophrenia 75% Maori vs. 67% non-Maori; bipolar disorder 55% Maori vs. 48% non-Maori) and those with no stable diagnosis at FEP were most likely to move towards a schizophrenia disorder diagnosis in both groups. Maori had a lower rate of diagnosed co-morbid affective and anxiety symptoms and higher rates of continued face to face contact and inpatient admission across all diagnoses. Conclusions Indigenous differences in schizophrenia and affective psychosis diagnoses could be related to differential exposure to socio-environmental risk or assessor bias. The lower rate of co-morbid affective and anxiety disorders indicates a potential under-appreciation of affective symptoms in Maori youth with first episode psychosis.

Automated summary

Differences in diagnoses between Maori and non-Maori in early psychosis persist over a five-year period. Maori are more likely to be diagnosed with schizophrenia, while non-Maori are more likely to be diagnosed with bipolar disorder. The stability of diagnoses is similar, and those with no stable diagnosis are more likely to move towards a schizophrenia diagnosis in both groups. Maori have a lower rate of diagnosed affective and anxiety disorders, but higher rates of face-to-face contact and inpatient admission.