The current program of research seeks to investigate new and emerging statistical models to develop accurate and efficient diagnostic instruments that measure the latent relationship between internalising (eg. depression, anxiety), externalising (eg. substance use, anti-social and conduct disorder) and thought disorders (eg. psychosis).
A growing body of empirical evidence has questioned the validity of categorical diagnostic instruments. Converging lines of evidence suggest that models of psychopathology that measure multiple disorders through the use of broad dimensional spectra offer a significant improvement to psychiatric research and clinical practice. This model is commonly referred to as a dimensional-spectrum model. In order to facilitate the use of dimensional models to measure the broad spectra of psychopathology there is a growing need for new assessment tools that measure the dimensionality of psychiatric disorders. Previously, dimensional instruments for individual disorders have been developed however no study has examined the possibility of constructing a tool that measures the complex latent relationship between putatively distinct disorders using a dimensional-spectrum model. Advances in measurement theory, particularly multidimensional Item Response Theory (IRT), offer innovative ways to measure broad dimensional constructs. These methods can be utilised for the development of efficient and accurate diagnostic tools through the use of computerised adaptive testing.
The current research program aims to develop and test an innovative and novel approach for diagnosing psychiatric disorders in community and clinical populations using a dimensional-spectrum model as the guiding theoretical framework.
This integrated research program will be divided into a series of studies that seek to determine the feasibility, to develop, and to test a novel instrument that assesses a dimensional-spectrum model of psychopathology. The research program will develop a large item pool of symptoms of psychiatric disorders informed by the previous literature, which include: internalising disorders (e.g. depression, generalised anxiety disorder, phobic disorders, PTSD), externalising disorders (e.g. substance use disorders, conduct/antisocial disorders), and thought control disorders (e.g. schizophrenia, psychosis, mania). The study will then test and calibrate the item pool in large-scale community and clinical samples utilising a comprehensive set of latent variable techniques, most notably Item Response Theory (IRT). The feasibility of various IRT models to develop the instrument will be examined. These estimated IRT parameters will then be validated in important subgroups of the population, including: gender, age, and ethnicity. The final aspect of the study will involve setting up a computerised adaptive test (CAT) to measure the underlying levels of psychopathology in a highly efficient and accurate manner. This will utilise data collected previously in a series of simulation runs that will aim to fine tune the CAT according to various selection and stopping rules.
Several analyses of existing national survey data from Australia and the United States have demonstrated the validity and utility of using dimensional approaches to assess comorbidity amongst substance use and mental disorders. Results of these studies have been published or are currently in submission for publication.
As part of a project grant with colleagues at ANU we have now finished collecting data on several large item pools that consist of diagnostic symptoms for eight mental and substance use disorders. These data will be analysed in order to form diagnostic screeners and adaptive tests including individual disorder adaptive tests as well as a higher order internalizing adaptive test. The results of the initial item selection procedure have been published. Additional manuscripts describing the item bank development and the construction of a short form distress scale have been accepted or in submission for publication. Data analyses to construct an adaptive version of a broad internalizing item bank and the thought disorder item bank are currently underway along with analyses that seek to develop disorder specific adaptive and static short forms (e.g. panic disorder and suicidality).
The results of the panic disorder and suicidality screener development studies have been presented at national and international conferences. A manuscript for the development and validation of the Internalising adaptive test are currently under consideration at Assessment. A manuscript reporting the development and validation of screening tools for panic disorder, obsessive compulsive disorder, and social anxiety disorder is currently under consideration at the International Journal of Methods in Psychiatric Research. The results of an Australian validation of the PROMIS depression and anxiety scales have been published in Assessment. A brief short form scale to measure general psychological distress has been developed and the results published in the Journal of Clinical Epidemiology. Finally, the results of a randomized controlled trial that investigated whether providing tailored feedback after assessment significantly improved mental health treatment seeking was conducted and the results are now in press at the British Journal of Psychiatry: Open.
A collaboration with colleagues at the University of Minnesota, Florida State University, and the University of Iowa has commenced in order to develop and examine the psychometric properties of an adaptive test to measure the latent constructs of externalizing, substance use, and callousness/aggression. The data analyses are complete and a copy of the manuscript is currently in press in Psychological Assessment.
Batterham., P. J., Calear, A. L., Sunderland, M., Carragher, N. Psychometric properties of 7- and 30-day versions of the PROMIS emotional distress item banks in an Australian adult sample. Assessment, in press.
Sunderland, M., Slade, T., Krueger, R. F., Markon, K. E., Patrick, C. J., Kramer, M. D. Efficiently measuring the higher-order dimensions of the Externalizing Spectrum model: development of the Externalizing Spectrum Inventory-Computerized Adaptive Test (ESI-CAT). Psychological Assessment, in press.
Batterham, P. J., Sunderland, M., Carragher, N., Calear, A. L., MacKinnon, A. J., Slade, T. (2016). The Distress Questionnaire-5: population screener for psychological distress was more accurate than the K6/K10. Journal of Clinical Epidemiology, 71, 35-42.
Carragher, N., Teesson, M., Sunderland, M., Newton, N. C., Krueger, R. F., Conrod, P. J., Barrett, E. L., Champion, K. E., Nair, N. K., Slade, T. (2016). The structure of adolescent self-report psychopathology: a symptom-level analysis. Psychological Medicine, 46(5), 981-994.
Sunderland, M., Carragher, N., Chapman, C., Mills, K., Teesson, M., Lockwood, E., Forbes, D., Slade, T. (2016). The shared and specific relationships between exposure to potentially traumatic events and transdiagnostic dimensions of psychopathology. Journal of Anxiety Disorders, 38, 102-109.
Sunderland, M., Slade, T. (2015). The relationship between internalizing psychopathology and suicidality, treatment seeking, and disability in the Australian population. Journal of Affective Disorders, 171, 6-12.
Sunderland, M., Slade, T., Krueger, R. F.(2015). Examining the shared and unique relationships among substance use and mental disorders. Psychological Medicine,45(05), 1103-1113.
Sunderland, M., Slade, T., Carragher, N., Batterham, P., Buchan, H. (2013). Age-related differences in internalizing psychopathology amongst the Australian general population. Journal of Abnormal Psychology, 122(4), 1010-1020.
Mewton, L., Hobbs, M. J., Sunderland, M., Newby, J., Andrews, G. (2014) Reduction in the internalizing trait following internet-delivered treatment for anxiety and depression in primary care. Behavior Research and Therapy, 63, 132-138.
Batterham, P. J., Brewer, J., Tjhin, A., Sunderland, M.,Carragher, N., Calear, A. L. (2015). Systematic item selection process applied to developing item pools for assessing multiple mental health problems. Journal of Clinical Epidemiology, 68(8), 913-919.
Carragher, N., Sunderland, M., Batterham, P J., Calear, A. L., Elhai, J., Chapman, C., Mills, K. (2016). Factor structure and gender differences in DSM-5 posttraumatic stress disorder symptoms: results from a nationally representative sample. Journal of Affective Disorders, 190, 56-67.
Batterham, P. J., Sunderland, M., Carragher, N., Calear, A. L., MacKinnon, A. J., Slade, T. The Distress Questionnaire-5: population screener for psychological distress was more accurate than the K6/K10. Journal of Clinical Epidemiology, in press.
Batterham, P. J., Calear, A., Sunderland, M., Carragher, N., Brewer, J. L. Online screening and feedback to increase help seeking for mental health problems: population-based randomized controlled trial. BJP Open, in press.
Conference presentations and Posters:
Sunderland, M. (2016). Adaptive tests for internalising and externalising: efficiency measuring broad levels of psychopathology. Accepted from abstract: Australasian Professional Society on Alcohol and other drugs annual conference, Sydney, Australia.
Sunderland, M., Slade, T., Krueger, R. F., Markon, K., Patrick, C., Kramer, M. (2016). Efficiently measuring liability to externalizing behaviours: development of the Externalizing Spectrum Inventory-Computerised Adaptive Test (ESI-CAT). Accepted from abstract: UNSW Brain Sciences Symposium, Sydney, Australia.
Sunderland, M., Batterham, P., Carragher, N., Calear, A. (2015). More efficient assessment of Panic Disorder in the community: Development and validation of the Rapid Measurement Toolkit for Panic Disorder (RMT-PD). Accepted from abstract: Social for Mental Health Research, Brisbane, Australia.
Sunderland, M., Batterham, P., Carragher, N., Calear, A. (2015). The Rapid Measurement Toolkit for Panic Disorder: development, validation, and normative data. Accepted from abstract: The 15th International congress of the IFPE, Bergen, Norway.
Sunderland, M., Slade, T. (2015). Efficiently measuring liability to externalizing behaviours: development of the Externalizing Spectrum Inventory-Computerized Adaptive Test (ESI-CAT). Accepted from abstract: NDARC Annual Symposium, Sydney, Australia.
Sunderland, M. (2015). Thinking outside the box: transdiagnostic conceptualisations of internalising disorders and treatment. Invited presentation: the annual Centre for Research Excellence in Mental Health and Substance Use colloquium, Canberra, Australia.
Sunderland, M., Slade, T. (2014). The centrality of latent variables when examining the correlates of mental and substance use disorders. Accepted from abstract: Society for Mental Health Research, Adelaide, December.
Brewer, J. L., Batterham, P. J., Sunderland, M., Carragher, N., Calear (2014) A. New item banks to assess mental health: item selection process. Accepted from abstract: Society for Mental Health Research, Adelaide, December.
Batterham, P. J., Sunderland, M., Carragher, N., Calear, A., Brewer, J. (2014) New item banks to assess mental health. Accepted from abstract: Society for Mental Health Research, Adelaide, December.
Sunderland, M., Slade, T., Krueger, R. F. (2013). Examining the shared and unique relationships among DSM-IV substance use and mental health conditions. Accepted from abstract: Australasian Society for Psychiatric Research conference, Melbourne, December.
Sunderland, M., Slade, T., Krueger, R. F. (2013). Examining the unique contribution of specific DSM-IV substance use disorders, over and above general externalizing psychopathology, when predicting anxiety disorders, affective disorders, suicidality, and psychosis. Accepted from Abstract: NDARC Annual Symposium, Sydney, September.
Considering some of the clinical applications, this research will provide a useful diagnostic tool that will assist in facilitating a dimensional approach to the assessment of psychiatric disorders in everyday clinical research. A dimensional approach offers the advantage of obtaining a greater amount of patient information, including the ability to measure the latent interaction between putatively distinct disorders as well as the ability to better distinguish between disorder severity levels. A dimensional approach will also provide clinicians and researchers with the ability to identify highly disordered cases that are in immediate need for treatment. Likewise, the choice of treatment will be influenced by the various severity levels and interaction between multiple disorders observed in each case, which will enable tailored treatment programs to be based on efficient and informative diagnoses.