Purdue University Graduate School
Bucher PhD 2022 (1).pdf (1.06 MB)

The longitudinal trajectory and client-therapist agreement of personality traits over the course of therapy

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posted on 2021-07-28, 02:42 authored by Meredith A BucherMeredith A Bucher

Personality traits are important factors of psychotherapy for many reasons, as they relate to a variety of clinical outcomes, can complicate treatment, and can also be targets of treatment interventions. Because of its clinical prevalence and impact, it is imperative that therapists are able to effectively assess and treat personality pathology. Previous research has indicated that both client and therapist ratings of personality can provide meaningful information, and this varies across different sessions, but no study to date has examined both client and therapist ratings across the entire therapeutic intervention. There is also limited information on the agreement of client and therapist ratings of personality, as the majority of studies only examine the outset, the end, or a random time point of treatment. Examining only one point in time – or just the beginning and end – misses valuable information regarding possible changes in personality occurring throughout treatment. Using a naturalistic dataset of 128 client-therapist dyads (3,440 observations), the present study examined the longitudinal trajectory of client and therapist ratings of personality change throughout intervention while also accounting for state-level distress. Additionally, the agreement between clients and therapists were examined throughout treatment for any potential patterns of change using rank-order, mean-level, and absolute agreement. Significant patterns of trait change and change in absolute agreement across treatment were assessed using multilevel modeling. Last but not least, the agreement among clients and therapists were examined as potential predictors of therapeutic outcomes, such as engagement and improvement. The results provided evidence for significant decreases in neuroticism that were reported by the client but not therapist that suggest clients might be report decreases in state-level distress rather than true trait change. There were meaningful fluctuations in agreement across treatment, particularly for openness to experience and neuroticism, but the overall agreement – or lack thereof – did not significantly predict client engagement or improvement. Results highlight several clinical implications that are discussed.


Degree Type

  • Doctor of Philosophy


  • Psychological Sciences

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Douglas Samuel

Additional Committee Member 2

Donald Lynam

Additional Committee Member 3

Brent Roberts

Additional Committee Member 4

Susan South