Reliability, validity, and clinical utility of a culturally modified Kessler scale (MK-K5) in the Aboriginal and Torres Strait Islander population

Background: Aboriginal and Torres Strait Islander peoples are the first people of Australia. Consequences of historic and contemporary settler-colonialism including racism, trauma, grief and loss (of land, culture, spirituality, and freedoms) have led to substantial negative health and wellbeing impacts. The Kessler Psychological Distress Scales are population and individual-level tools designed to measure general psychological health status. There has been limited assessment of the psychometric properties and validity of the Kessler Psychological Distress Scale for use with the Aboriginal and Torres Strait Islander population in Australia, despite its widespread use. Methods: A national sample of Aboriginal and Torres Strait Islander adults (n = 6988 ≥ 16 years) was used in the psychometric assessment of the MK-K5, which involved face validity, acceptability, internal consistency/reliability, construct validity, and convergent and divergent validity testing. Receiver Operator Characteristics (ROC) curves were produced to assess clinical utility for depression and anxiety screening. Results: The MK-K5 demonstrated face validity for psychological distress in two focus groups, and had good acceptability, good internal consistency/reliability (α = 0.89), good construct validity (uni-dimensional; one underlying component explaining 70.1% of variance), and demonstrated convergent and divergent validity in the sample. The MK-K5 had good clinical utility at a cut-off score of 11 for detecting ever being diagnosed with depression or anxiety. Conclusions: The MK-K5 is a valid measure of psychological distress and has clinical utility in the Aboriginal and Torres Strait Islander population.