Research

The bibliography behind the scales

247 references support the manual’s practice model, drawn from studies of first episode psychosis and early intervention services worldwide.

Below are the entries where the scales’ principal developer, Dr Donald Addington, is a listed author or co-author.

• Sim, A., Ting, Q. M. J., Tay, Y. L., Ang, S., Addington, D., Tang, C., & Verma, S. (2026). Adapting the First Episode Psychosis Services Fidelity Scale in Asia: A Comprehensive Evaluation of Singapore's Early Psychosis Intervention Programme. Early Interv Psychiatry, 20(1), e70131. doi:10.1111/eip.70131

• Savill, M., Banks, L. M., Sepulveda, B. T., Ho, S., Tryon, V. L., Nye, K. E., . . . Addington, D. E. (2025). Development of the Clinical High Risk for Psychosis Services Fidelity Scale (CHRPS-FS) for Team-Based Care. Psychiatr Serv, 76(4), 373–380. doi:10.1176/appi.ps.20240107

• Tan, S. L., Kirkham, J., & Addington, D. (2025). The First Episode Psychosis Services Fidelity Scale as a Measure of Quality of Care. Schizophr Bull Open, 6(1), sgaf030. doi:10.1093/schizbullopen/sgaf030

• Addington, D., Marshall, T., Rosenblatt, A., Bond, G., & Goldman, H.H. (2024). Standardizing Fidelity to Evidence-Based Practice in the Early Psychosis Intervention Network. Psychiatric Services, 75(10), 1031–1034. doi:10.1176/appi.ps.20230556

• Tomaskova, H., Kondratova, L., Winkler, P., & Addington, D. (2023). Development and implementation of fidelity assessment in first episode psychosis services in Czechia: A pilot study. Early Interv Psychiatry, 17(6), 573–580. doi:10.1111/eip.13350

• Addington, D., French, P. , & Smith, J. (2022). A comparison of the National Clinical Audit of Psychosis 2019/2020 standards and First Episode Psychosis Services Fidelity Scale 1.0. Early Intervention in Psychiatry, 16(9), 1028–1035. doi:https://doi.org/10.1111/eip.13262

• Addington, D. (2021a). The First Episode Psychosis Services Fidelity Scale 1.0: A Review and update. Schizophrenia Bulletin Open, 2(1), 9.

• Addington, D. (2021b). First Episode Psychosis Services Fidelity Scale and Manual. Calgary, Alberta, Canada: University of Calgary Press.

• Addington, D., Cheng, C. C., French, P., Killackey, E., Melau, M., Meneghelli, A., . . . Smith, J. (2021). International application of standards for health care quality, access and evaluation of services for early intervention in psychotic disorders. Early Intervention in Psychiatry, 15(3), 723–730. doi:10.1111/eip.12990

• Addington, Donald E. (2021). First Episode Psychosis Services Fidelity Scale (FEPS-FS 1.0) and Manual.

• Selick, Avra, Langill, Gordon, Cheng, Chiachen, Addington, Donald, Archie, Suzanne, Butt, Shannel, & Durbin, Janet. (2021). Feasibility and acceptability of a volunteer peer fidelity assessment model in early psychosis intervention programmes in Ontario: Results from a pilot study. Early Intervention in Psychiatry, 15(3), 480–485. doi:https://doi.org/10.1111/eip.12961

• Addington, D., Noel, V., Landers, M., & Bond, G. R. (2020). Reliability and Feasibility of the First-Episode Psychosis Services Fidelity Scale-Revised for Remote Assessment. Psychiatr Serv, 71(12), 1245–1251. doi:10.1176/appi.ps.202000072

• Cadenhead, K. S., Minichino, A., Kelsven, S., Addington, J., Bearden, C., Cannon, T. D., . . . Yao, J. (2019). Metabolic abnormalities and low dietary Omega 3 are associated with symptom severity and worse functioning prior to the onset of psychosis: Findings from the North American Prodrome Longitudinal Studies Consortium. Schizophr Res, 204, 96–103. doi:10.1016/j.schres.2018.09.022

  Jean Addington is an author on this reference; Donald Addington is not.

• Durbin, J., Selick, A., Langill, G., Cheng, C., Archie, S., Butt, S., & Addington, D. E. (2019). Using Fidelity Measurement to Assess Quality of Early Psychosis Intervention Services in Ontario. Psychiatr Serv, 70(9), 840–844. doi:10.1176/appi.ps.201800581

• Addington, D., Birchwood, M., Jones, P., Killackey, E., McDaid, D., Melau, M., . . . Nordentoft, M. (2018). Fidelity scales and performance measures to support implementation and quality assurance for first episode psychosis services. Early Interv Psychiatry, 12(6), 1235–1242. doi:10.1111/eip.12684

• Pringsheim, T., Gardner, D., Addington, D., Martino, D., Morgante, F., Ricciardi, L., . . . Barnes, T. R. E. (2018). The Assessment and Treatment of Antipsychotic-Induced Akathisia. Can J Psychiatry, 706743718760288. doi:10.1177/0706743718760288

• Addington, D., Abidi, S., Garcia-Ortega, I., Honer, W. G., & Ismail, Z. (2017). Canadian Guidelines for the Assessment and Diagnosis of Patients with Schizophrenia Spectrum and Other Psychotic Disorders. Can J Psychiatry, 62(9), 594–603. doi:10.1177/0706743717719899

• Addington, D., Anderson, E., Kelly, M., Lesage, A., & Summerville, C. (2017). Canadian Practice Guidelines for Comprehensive Community Treatment for Schizophrenia and Schizophrenia Spectrum Disorders. Can J Psychiatry, 62(9), 662–672. doi:10.1177/0706743717719900

• Addington, J., Addington, D., Abidi, S., Raedler, T., & Remington, G. (2017). Canadian Treatment Guidelines for Individuals at Clinical High Risk of Psychosis. Can J Psychiatry, 62(9), 656–661. doi:10.1177/0706743717719895

  Both Donald Addington and Jean Addington are authors on this reference.

• Addington, D.E., Norman, R., Bond, G.R., Sale, T., Melton, R., Mckenzie, E., & Wang, J. (2016). Development and Testing of the First-Episode Psychosis Services Fidelity Scale. Psychiatr. Serv, 67(9), 1023–1025.

• Buchy, L., Cadenhead, K. S., Cannon, T. D., Cornblatt, B. A., McGlashan, T. H., Perkins, D. O., . . . Addington, J. (2015). Substance use in individuals at clinical high risk of psychosis. Psychological Medicine, 45(11), 2275–2284. doi:10.1017/S0033291715000227

  Jean Addington is an author on this reference; Donald Addington is not.

• Mueser, K.T., Penn, D.L., Addington, J., Brunette, M.F., Gingerich, S., Glynn, S.M., . . . Kane, J.M. (2015). The NAVIGATE Program for First-Episode Psychosis: Rationale, Overview, and Description of Psychosocial Components. Psychiatr. Serv, appips201400413. doi:10.1176/appi.ps.201400413 [doi]

  Jean Addington is an author on this reference; Donald Addington is not.

• Addington, Jean, Case, Nevicia, Saleem, Majid M., Auther, Andrea M., Cornblatt, Barbara A., & Cadenhead, Kristin S. (2014). Substance use in clinical high risk for psychosis: a review of the literature. Early Intervention in Psychiatry, 8(2), 104–112. doi:https://doi.org/10.1111/eip.12100

  Jean Addington is an author on this reference; Donald Addington is not.

• Miklowitz, David, O’Brien, Mary, Schlosser, Danielle, Addington, Jean, Candan, Kristin, Marshall, Catherine, . . . Cannon, Tyrone. (2014). Family-Focused Treatment for Adolescents and Young Adults at High Risk for Psychosis: Results of a Randomized Trial. Journal of the American Academy of Child & Adolescent Psychiatry, 53(8), 10. doi:10.1016/j.jaac.2014.04.020

  Jean Addington is an author on this reference; Donald Addington is not.

• Addington, D.E., Mckenzie, E., Norman, R., Wang, J., & Bond, G.R. (2013). Essential Evidence-Based Components of First-Episode Psychosis Services. Psychiatr. Serv, 64(5), 452–457.

• Fusar-Poli, P., Borgwardt, S., Bechdolf, A., Addington, J., Riecher-Rossler, A., Schultze-Lutter, F., . . . Yung, A. (2013). The psychosis high-risk state: a comprehensive state-of-the-art review. JAMA Psychiatry, 70(1), 107–120. doi:10.1001/jamapsychiatry.2013.269

  Jean Addington is an author on this reference; Donald Addington is not.

• Addington, D. E., Beck, C., Wang, J., Adams, B., Pryce, C., Zhu, H., . . . McKenzie, E. (2010). Predictors of admission in first-episode psychosis: developing a risk adjustment model for service comparisons. Psychiatr Serv, 61(5), 483–488. doi:10.1176/ps.2010.61.5.483

• Addington, D., Kyle, T., Desai, S., & Wang, J. (2010). Facilitators and barriers to implementing quality measurement in primary mental health care: Systematic review. Can Fam Physician, 56(12), 1322–1331.

• Addington, D., Norman, R., Adair, C., Manchanda, R., Mckenzie, E., Mitchell, B., & Pryce, C. (2009). A comparison of early psychosis treatment services using consensus and evidenced-based performance measures; moving towards setting standards. Early Intervention in Psychiatry, 3(4), 274–281.

• Addington, D., Addington, M. D., & Patten, S. (2007). Relapse rates in an early psychosis treatment service. Acta Psychiatr Scand, 115(2), 126–131. doi:10.1111/j.1600-0447.2006.00879.x

• Addington, D., McKenzie, E., Addington, J., Patten, S., Smith, H., & Adair, C. (2007a). Performance measures for evaluating services for people with a first episode of psychosis. Early Intervention in Psychiatry, 1(2), 157–167. doi:10.1111/j.1751-7893.2007.00020.x

  Both Donald Addington and Jean Addington are authors on this reference.

• Addington, D., Mckenzie, E., Addington, J., Patten, S., Smith, H., & Adair, C. (2007b). Performance measures for evaluating services for people with a first episode psychosis. Early Intervention in Psychiatry, 1, 157–167. doi:doi:10.1111/j.1751-7893.2007.00020.x

  Both Donald Addington and Jean Addington are authors on this reference.

• McGlashan, T.H., Zipursky, R.B., Perkins, D., Addington, J., Miller, T., Woods, S.W., . . . Breier, A. (2006). Randomized, double-blind trial of olanzapine versus placebo in patients prodromally symptomatic for psychosis. Am. J. Psychiatry, 163(5), 790–799.

  Jean Addington is an author on this reference; Donald Addington is not.

• Addington, D., Mckenzie, E., Addington, J., Patten, S., Smith, H., & Adair, C. (2005). Performance measures for early psychosis treatment services. Psychiatric Services, 56(12), 1570–1582.

  Both Donald Addington and Jean Addington are authors on this reference.

• Addington, J., Young, J., & Addington, D. (2003). Social outcome in early psychosis. Psychol. Med, 33(6), 1119–1124.

  Both Donald Addington and Jean Addington are authors on this reference.