The Kessler Psychological Distress Scale in Australian adolescents: Analysis of the second Australian Child and Adolescent Survey of Mental Health and Wellbeing.

Introduction: The 10-item Kessler Psychological Distress Scale (K10) is used to screen adolescents for mental disorders in Australian clinical practice; however, there are no Australian adolescent normative data.

Methods: Data were drawn from a nationally representative sample (N = 2964) of Australian adolescents (11-17 years). This study had three aims: (1) to examine concurrent validity between the K10 and Strengths and Difficulties Questionnaire (SDQ) emotional symptoms subscale, (2) to establish normative Australian adolescent K10 data and (3) to determine optimal K10 cut-off scores for screening for major depressive disorder (MDD) via receiver operator characteristic curve analysis and stratum-specific likelihood ratios.

Results: The K10 and SDQ emotional symptoms scales were moderately correlated (r_s = 0.63, p < 0.001). Older female adolescents reported higher total K10 scores compared with younger female adolescents (15-17 years: M = 20.2, standard error [SE] = 0.3; 11-14 years: M = 16.8, SE = 0.3) and male adolescents (11-14 years: M = 16.6, SE = 0.2; 15-17 years: M = 16.0, SE=0.2). K10 scores to optimally discriminate those with and without MDD varied by age and sex and had low specificities. Stratum-specific likelihood ratios indicated adolescents with a K10 score of ≥30 will have a 12.9 (95% confidence interval = [10.2, 16.2]) increased likelihood of MDD.

Conclusion: The K10 has utility for assessing psychological distress in health care and epidemiological research in Australian adolescents. Adolescents with K10 scores in the 'very high' range are at increased risk of MDD. Further assessment of these young people is indicated to identify those with or at risk of developing MDD.