I am a Consultant Clinical Psychologist in the NHS (RDASH NHS Foundation Trust) working in an in-patient setting and I am also an Honorary Senior Lecturer at the University of Sheffield. I have worked in the NHS for many years in therapy services, training, supervision and senior management.
After completing my core CAT training in Manchester I have since qualified as a CAT psychotherapist. I am a trainer for the Catalyse/CAT North CAT Practitioner Training course and teach on CAT training courses around the country.
I strive to increase the evidence base for CAT. Current research includes conducting:
- a large patient preference randomised controlled trial of psychoeducational CAT for anxiety in Pennine Care NHS Foundation Trust
- a pilot and feasibility study of integrating repertory grids into the reformulation and ending process in the Manchester Specialist Psychotherapy Service.
- a meta analysis of idiographic change during CAT
Clinically, my real interest centres on helping people with long-standing interpersonal problems with the CAT model and approach and helping systems to work better around the service user using a CAT consultancy approach.
Gaskell, C., Kellett, S., Simmonds-Buckley, M., Curran, J., Hetherington, J., & Delgadillo, J. (2023). Long-term psychotherapy in tertiary care: A practice-based benchmarking study. British Journal of Clinical Psychology, 00, 1– 18. https://doi.org/10.1111/bjc.12424
Power, N., Kellett, S., & Gaskell, C. (2023). Effectiveness of cognitive analytic therapy for mixed anxiety and depression in the context of borderline traits: A quasi-experimental single case design evaluation. Journal of Psychotherapy Integration, 33(1), 34–46. https://doi.org/10.1037/int0000281
Easton K , Kellett S , Cooper M , Millings A , Varela J , Parry G (2021),
Blending Cognitive Analytic Therapy With a Digital Support Tool: Mixed Methods Study Involving a User-Centered Design of a Prototype App. JMIR Ment Health 2021;8(2): e20213 doi: 10.2196/20213
Stephen Kellett & Daniel Stockton (2021) Treatment of obsessive morbid jealousy with cognitive analytic therapy: a mixed-methods quasi-experimental case study, British Journal of Guidance & Counselling, DOI: 10.1080/03069885.2021.1929834
Merzhvynska, M. Simmonds-Buckley, M., Delgadillo, J., & Kellett, S. (2021). Trajectories of change in the therapeutic alliance during Cognitive Analytic Therapy for depression. Psychology and Psychotherapy Theory Research and Practice.
Wakefield, S., Delgadillo, J., Kellett, S., White, S. & Hepple, J. (2021) The effectiveness of brief cognitive analytic therapy for anxiety and depression: A quasi‐experimental case-control study. British Journal of Clinical Psychology. Early View (Open Access)
Kellett, S., Gausden, J. and Gaskell, C. (2020), The effectiveness of cognitive analytic therapy for borderline personality disorder: Utilizing a withdrawal experimental design to improve sensitivity to abandonment. Psychol Psychother Theory Res Pract. https://doi.org/10.1111/papt.12278
Hallam, Craig & Simmonds-Buckley, Mel & Kellett, Stephen & Greenhill, Beth & Jones, Andrew. (2020). The acceptability, effectiveness, and durability of cognitive analytic therapy: Systematic review and meta‐analysis. Psychology and Psychotherapy: Theory, Research and Practice. 10.1111/papt.12286.
Kellett, S., Bee, C., Aadahl, V., Headley, E., & Delgadillo, J. (2020). A pragmatic patient preference trial of cognitive behavioural versus cognitive analytic guided self-help for anxiety disorders. Behavioural and Cognitive Psychotherapy, 1-8. doi:10.1017/S1352465820000442
Kellett S, Easton K, Cooper M, Millings A, Simmonds-Buckley M, Parry G (2020) Evaluation of a Mobile App to Enhance Relational Awareness and Change During Cognitive Analytic Therapy: Mixed Methods CaseSeries. JMIR Ment Health 2020;7(12): e19888 URL: http://mental.jmir.org/2020/12/e19888/ doi: 10.2196/19888
S Kellett, J Ghag, K Ackroyd, K Freshwater, J Finch, A Freear, J Hartley & M Simmonds‐Buckley (2019) . Delivering cognitive analytic consultancy to community mental health teams: Initial practice‐based evidence from a multi‐site evaluation. Psychology and Psychotherapy: Theory Research and Practice. Early View 28 March 2019 (Open Access)
Kellett, S., & Lees, S. (2019). Quasi-experimental N = 1 evaluation of the effectiveness of cognitive analytic therapy for dependent personality disorder. Journal of Psychotherapy Integration. Advance online publication.
Spence C, Kellett S, Totterdell P, Parry G. (2019) Can cognitive analytic therapy treat hoarding disorder? An adjudicated hermeneutic single‐case efficacy design evaluation. Clin Psychol Psychother. 2019; 1–11.
Kellett, S. Stockton, C., Marshall, H., Hall, J. Jennings, C., & Degadillo, J. (2018). Efficacy of narrative reformulation during cognitive analytic therapy for depression: randomized dismantling trial. Journal of Affective Disorders, 239, 37-47.
Curling L. , Kellett, S., Totterdell, P., Parry, G., Hardy, G., & Berry, K. (2018). Treatment of obsessive morbid jealousy with cognitive analytic therapy: An adjudicated hermeneutic single-case efficacy design evaluation. Psychology and Psychotherapy; Theory, Research and Practice, 91, 95-116.
Kellett, S., Hall, J., & Compton-Dickinson, S. (2018). Group cognitive analytic music therapy: a quasi-experimental feasibility study conducted in a high secure hospital. Nordic Journal of Music Therapy, doi: 10.1080/08098131.2018.1529697
Evans, M., Kellett, S., Heywood, S., Hall, J., & Majid, S. (2017). Cognitive analytic therapy for bipolar disorder: A pilot randomized controlled trial. Clinical Psychology and Psychotherapy, 24, 22-35.
Sandhu SK, Kellett S & Hardy G (2017) The development of a change model of “exits” during cognitive analytic therapy for the treatment of depression. Clinical Psychology and Psychotherapy 0, pp 1 – 11
Berrios, R., Kellett, S., Fiorani, C., & Poggioli, M. (2016). Assessment of identity disturbance: Factor Structure and validation of the Personality Structure Questionnaire (PSQ) in an Italian sample. Psychological Assessment, 28, 27-35
Kellett, S. & Bennett, D. (2016) Integration of competency assessment into CAT supervision: A practical guide. Chapter 11, pp 149 – 162 in D Pickvance (ed) (2016) Cognitive Analytic Supervision: A relational approach. Routledge
Kellett S, Simmonds-Buckley M & Totterdell P (2016) Testing the Effectiveness of Cognitive Analytic Therapy for Hypersexuality Disorder: An Intensive Time-Series Evaluation. Journal of Sex & Marital Therapy pp 501 – 516
Kellett, S. Wilbram, M., Davis, C. & Hardy, G. (2014). Team consultancy using cognitive analytic therapy: a controlled study in assertive outreach. Journal of Psychiatric and Mental Health Nursing, 21, 687-97
Kellett, S. & Totterdell, P. (2013). Taming the green-eyed monster: temporal responsivity to cognitive behavioural and cognitive analytic therapy for morbid jealousy. Psychology and Psychotherapy; Theory, Research and Practice, 39, 52-69
Kellett, S. Bennett, D. Ryle, A. & Thake, A. (2013). Cognitive Analytic Therapy for Borderline Personality Disorder: Therapist competence and therapeutic effectiveness in routine practice. Clinical Psychology and Psychotherapy, 20, 216-225
Kellett, S. (2012). In Feltham, C. & Horton, I. The SAGE Handbook of Counselling and Psychotherapy (third edition). Cognitive Analytic Therapy (pp 343-350). Sage
Marriott, M. & Kellett, S. (2009). Evaluating a cognitive analytic therapy service; practice-based outcomes and comparisons with person-centred and cognitive-behavioural therapies. Psychology and Psychotherapy; Theory, Research and Practice, 82, 57-82
Kellett, S. (2007). The treatment of Histrionic Personality Disorder with Cognitive Analytic Therapy; a time series evaluation. Psychology and Psychotherapy; Theory, Research and Practice, 80, 389-405