Authors’ reply

Abstract

Edited by Kiriakos Xenitidis and Colin Campbell Contents ▪ Prevalence: are two-fifths of young people really 'abnormal'? ▪ Authors' reply Prevalence: are two-fifths of young people really 'abnormal'? We read with interest Deighton and colleagues' paper about mental health problems among 11-to 14-year-olds. 1 They stress the importance of understanding prevalence and report 'findings that indicate the scale of mental health problems in England is much higher than previous estimates'. The previous estimates referred to are from England's Mental Health of Children and Young People (MHCYP) survey, which recently identified 13.6% of 11to 15-year-olds as meeting the diagnostic criteria for a mental disorder. 2 They do not explain why their estimate of 42.5% is more reliable. Their survey was conducted in six of the most deprived local authorities in the country: Blackpool, Cornwall, Hull, Kent, Newham and Wolverhampton. The MHCYP survey was nationally representative. As expected, given the deprived areas sampled, children eligible for free school meals were overrepresented, as well as White pupils. These characteristics are associated with higher rates of disorder, 3 but are not addressed with the use of survey weights. The MHCYP survey used a complex weighting strategy to correct for selection and non-response biases to ensure that the sample was representative. Only the child self-report Strengths and Difficulties Questionnaire (SDQ) was used. The single-informant SDQ is a less reliable predictor of child mental disorder than the multi-informant SDQ, and the child self-report measure is less reliable than the parent or teacher measures. 4 In contrast, the MHCYP used a multi-informant standardised diagnostic assessment; the Development and Wellbeing Assessment. This combines highly structured and semi-structured questions, as well as clinical rating to triangulate child, parent and teacher reports and assign ICD-10 diagnoses. 5 Prevalence estimates rely on the thresholds applied. To identify pupils with problems in each of the four domains examined the authors have used a no longer recommended 'three band' approach and, 6 crucially, do not appear to have taken account of impact. Similarly, the overall threshold was derived by a score above the subscale cut-point on four of six possible subscales. This unusual approach was not explained, although we are sympathetic to the challenges of describing complex methodology within a short report. The standard approach would be to apply a threshold to the SDQ total difficulties score. 4 We disagree, therefore that the authors' findings indicate that the MHCYP's rates are underestimates. Poor mental health can be conceptualised in a number of ways, and clarity about definitions, especially when making comparisons, is essential.

Age Appropriateness of the Self-Report Strengths and Difficulties Questionnaire

“…Though the self-report SDQ is widely used, including to study age differences (Deighton et al, 2019;Hafekost et al, 2016;Johnston & Gowers, 2005), evidence of its age SDQ AGE APPROPRIATENESS 18 appropriateness has been limited. Building on existing evidence (He et al, 2013;Patalay et al, 2018) we addressed this gap by considering the measure's item-level readability, item quality, factor structure, and age measurement invariance.…”

“…Where measures lack proposed dimensionality, as is the case with the self-report SDQ (Goodman et al, 2010;Goodman, 2001;Percy et al, 2008), and invariance testing is warranted, given recent claims about age (Deighton et al, 2019;Dray et al, 2016;NHS Digital, 2018), exploratory structural equation modelling (ESEM) techniques can be used (Marsh, Nagengast, & Morin, 2013a). As others have pointed out, though ESEM structures should not be used to conceal problems with a measure, they can provide a more realistic framework for measurement invariance analysis where CFA models do not fit sufficiently well (Tóth-Király, Bõthe, Rigó, & Orosz, 2017).…”

“…This lack of clear support for the self-report SDQ's factor structure suggests a need for more detailed examination of its psychometric qualities, as has been explicitly called for in a SDQ AGE APPROPRIATENESS 6 recent systematic review (Bentley, Hartley, & Bucci, 2019). This is particularly necessary given the centrality of the measure in adolescent mental health research (e.g., Deighton et al, 2019;Dray et al, 2016;Hafekost et al, 2016;NHS Digital, 2018;Polanczyk et al, 2015;Wigelsworth, Humphrey, & Lendrum, 2012). Although evidence based on the SDQ suggests an increase in mental health difficulties in mid adolescence, around ages 14-15 (Deighton et al, 2019;Dray et al, 2016), it is not clear whether differences between early adolescents, around ages 11-12, and the 14-15 age group are due to differences in measurement properties, or the SDQ's high reading age (Patalay et al, 2018).…”

“…This is particularly necessary given the centrality of the measure in adolescent mental health research (e.g., Deighton et al, 2019;Dray et al, 2016;Hafekost et al, 2016;NHS Digital, 2018;Polanczyk et al, 2015;Wigelsworth, Humphrey, & Lendrum, 2012). Although evidence based on the SDQ suggests an increase in mental health difficulties in mid adolescence, around ages 14-15 (Deighton et al, 2019;Dray et al, 2016), it is not clear whether differences between early adolescents, around ages 11-12, and the 14-15 age group are due to differences in measurement properties, or the SDQ's high reading age (Patalay et al, 2018). Indeed, measurement invariance between different age groups is yet to be examined, which we therefore sought to address in the current study.…”

Young People’s Coping Strategies When Dealing With Their Own and a Friend’s Symptoms of Poor Mental Health: A Qualitative Study

“…One in five adolescents experience symptoms of poor mental health, such as depression or anxiety (Deighton et al, 2018). A recent meta-analysis, showed that 41.5% of individuals experience their first symptoms by the age of 14 years old, irrespective of the mental illness diagnosis (Solmi et al, 2021).…”