An investigation of treatment return after psychological therapy for depression and anxiety.

BACKGROUND: Some patients return for further psychological treatment in routine services, although it is unclear how common this is, as scarce research is available on this topic. AIMS: To estimate the treatment return rate and describe the clinical characteristics of patients who return for anxiety and depression treatment. METHOD: A large dataset (N=21,029) of routinely collected clinical data (2010-2015) from an English psychological therapy service was analysed using descriptive statistics. RESULTS: The return rate for at least one additional treatment episode within 1-5 years was 13.7%. Furthermore, 14.5% of the total sessions provided by the service were delivered to treatment-returning patients. Of those who returned, 58.0% continued to show clinically significant depression and/or anxiety symptoms at the end of their first treatment, while 32.0% had experienced a demonstrable relapse before their second treatment. CONCLUSIONS: This study estimates that approximately one in seven patients return to the same service for additional psychological treatment within 1-5 years. Multiple factors may influence the need for additional treatment, and this may have a major impact on service activity. Future research needs to further explore and better determine the characteristics of treatment returners, prioritise enhancement of first treatment recovery, and evaluate relapse prevention interventions.

Cognitive change before sudden gains in cognitive behavioural therapy for panic disorder.

BACKGROUND: Sudden gains occur in a range of disorders and treatments and are of clinical and theoretical significance if they can shed light on therapeutic change processes. This study investigated the relationship between sudden gains in panic symptoms and preceding cognitive change during cognitive behavioural therapy (CBT) for panic disorder. METHOD: Participants with panic disorder completed in session measures of panic symptoms and catastrophic cognitions. Independent samples t-tests were used to compare the post-treatment score of those who met criteria for one or more sudden gain during treatment with those who did not, and to compare within-session cognitive change between pre-sudden gain sessions and the previous (control) session. RESULTS: Twenty-two (42%) of 53 participants experienced a sudden gain during treatment. Participants demonstrating a sudden gain showed more improvement in panic symptoms from pre- to post-treatment than those without a sudden gain. The within-session cognitive change score in the pre-gain session was significantly greater than in the control session. CONCLUSIONS: Sudden gains occurred in individual CBT for panic disorder and within-session cognitive change was associated with sudden gains. This is consistent with the cognitive model of panic disorder and highlights how sudden gains can help to identify key change processes.

First impressions matter: The influence of initial assessments on psychological treatment initiation and subsequent dropout.

OBJECTIVE: This study investigated if patients' experience of an initial assessment may be associated with outcome expectations, and with subsequent treatment attendance. METHOD: The sample comprised n = 6051 patients with depression/anxiety disorders, nested within k = 148 assessing therapists. Multilevel modelling (MLM) was used to examine therapist effects on treatment initiation and subsequent dropout, adjusting for patient-level characteristics. We tested associations between early outcome expectancy measured at an initial assessment with attendance at a first therapy session, and with dropout after initiation. Variability in mean expectancy ratings in the caseloads of assessing therapists was examined using the intracluster correlation coefficient (ICC). RESULTS: Therapist effects partly explained the variance in treatment initiation and dropout. Pre-treatment outcome expectations significantly predicted treatment initiation but not dropout for the subgroup of patients who started treatment. Approximately 16% of variability in mean expectancy ratings was explained by therapist effects (ICC = 0.159) after controlling for patient-level covariates. CONCLUSIONS: Patients assessed by some therapists are more likely to have higher outcome expectations, which influences their decision to initiate treatment thereafter. Once patients start therapy, early expectancy measured at assessment no longer influences their attendance, but the "first impression" from an initial assessment does influence their subsequent likelihood of dropout.

The efficacy of individual humanistic-experiential therapies for the treatment of depression: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: Conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the efficacy of individual humanistic-experiential therapies (HEPs) for depression. METHOD: Database searches (Scopus, Medline, and PsycINFO) identified RCTs comparing any HEP intervention with a treatment-as-usual (TAU) control or active alternative intervention for the treatment of depression. Included studies were assessed using the Risk of Bias 2 tool and narratively synthesized. Post-treatment and follow-up effect sizes were aggregated using random-effects meta-analysis and moderators of treatment effect were explored (PROSPERO: CRD42021240485). RESULTS: Seventeen RCTs, synthesized across four meta-analyzes, indicated HEP depression outcomes were significantly better than TAU controls at post-treatment (g = 0.41, 95% CI [0.18, 0.65], n = 735), but not significantly different at follow-up (g = 0.14, 95% CI [-0.30, 0.58], n = 631). HEP depression outcomes were comparable to active treatments at post-treatment (g = -0.09, 95% CI [-0.26, 0.08], n = 2131), but significantly favored non-HEP alternative interventions at follow-up (g = -0.21, 95% CI [-0.35, -0.07], n = 1196). CONCLUSION: Relative to usual care, HEPs are effective in the short-term and comparable to non-HEP alternative interventions at post-treatment, but not at follow-up. However, imprecision, inconsistency, and risk of bias concerns were identified as limitations of the evidence included. Future large-scale trials of HEPs with equipoise between comparator conditions are required.

An examination of therapists' professional characteristics as moderators of the effect of feedback on psychological treatment outcomes.

Feedback-informed treatment (FIT) has been shown to reduce the gap between more and less effective therapists. This study aimed to examine therapists' professional characteristics as potential moderators of the effect of feedback on treatment outcomes.The IAPT-FIT Trial was a clinical trial where therapists were randomly assigned to a FIT group or a usual care control group. Treatment response was monitored using measures of depression (PHQ-9), anxiety (GAD-7) and functional impairment (WSAS). In a secondary analysis of this trial (n = 1,835 patients; t = 67 therapists), we used multilevel modelling to examine interactions between therapists' professional characteristics (e.g., attitude towards and self-efficacy regarding feedback utilization, decision-making style, job satisfaction, burnout, difficulties in practice, coping styles, caseload size) with random allocation (FIT vs. controls) to identify moderators of the effects of feedback.Between 9.6% and 10.8% of variability in treatment outcomes was attributable to therapist effects. Therapist-level caseload sizes and external feedback propensity (EFP) moderated the effect of feedback on depression outcomes. No statistically significant main effects were found for any of the included therapist characteristics.FIT reduced variability in outcomes between therapists and was particularly effective for therapists with high EFP and larger caseloads.

Individual treatment selection for patients with post-traumatic stress disorder: External validation of a personalised advantage index.

OBJECTIVE: To test the predictive accuracy and generalisability of a personalised advantage index (PAI) model designed to support treatment selection for Post-Traumatic Stress Disorder (PTSD). METHOD: A PAI model developed by Deisenhofer et al. (2018) was used to predict treatment outcomes in a statistically independent dataset including archival records for N = 152 patients with PSTD who accessed either trauma-focussed cognitive behavioural therapy or eye movement desensitisation and reprocessing in routine care. Outcomes were compared between patients who received their PAI-indicated optimal treatment versus those who received their suboptimal treatment. RESULTS: The model did not yield treatment specific predictions and patients who had received their PAI-indicated optimal treatment did not have better treatment outcomes in this external validation sample. CONCLUSION: This PAI model did not generalise to an external validation sample.

The Importance of Conducting Practice-oriented Research with Underserved Populations.

There has been a growing emphasis on dissemination of empirically supported treatments. Dissemination, however, should not be restricted to treatment. It can and, in the spirit of the scientific-practitioner model, should also involve research. Because it focuses on the investigation of clinical routine as it takes place in local settings and because it can involve the collaboration of several stakeholders, practice-oriented research (POR) can be viewed as an optimal research method to be disseminated. POR has the potential of addressing particularly relevant gaps of knowledge and action when implemented in regions of the world that have limited resources for or experiences with empirical research, and/or in clinical settings that are serving clinical populations who are not typically receiving optimal mental care services - specifically, individuals in rural and inner cities that have limited economic and social resources. The establishment and maintenance of POR in such regions and/or settings, however, come with specific obstacles and challenges. Integrating the experiences acquired from research conducted in various continents (Africa, Europe, Latin America, and North America), the goal of this paper is to describe some of these challenges, strategies that have been implemented to address them, as well as new possible directions to facilitate the creation and growth of POR. It also describes how these challenges and ways to deal with them can provide helpful lessons for already existing POR infrastructures.

Using Progress Feedback to Enhance Treatment Outcomes: A Narrative Review.

We face increasing demand for greater access to effective routine mental health services, including telehealth. However, treatment outcomes in routine clinical practice are only about half the size of those reported in controlled trials. Progress feedback, defined as the ongoing monitoring of patients' treatment response with standardized measures, is an evidence-based practice that continues to be under-utilized in routine care. The aim of the current review is to provide a summary of the current evidence base for the use of progress feedback, its mechanisms of action and considerations for successful implementation. We reviewed ten available meta-analyses, which report small to medium overall effect sizes. The results suggest that adding feedback to a wide range of psychological and psychiatric interventions (ranging from primary care to hospitalization and crisis care) tends to enhance the effectiveness of these interventions. The strongest evidence is for patients with common mental health problems compared to those with very severe disorders. Effect sizes for not-on-track cases, a subgroup of cases that are not progressing well, are found to be somewhat stronger, especially when clinical support tools are added to the feedback. Systematic reviews and recent studies suggest potential mechanisms of action for progress feedback include focusing the clinician's attention, altering clinician expectations, providing new information, and enhancing patient-centered communication. Promising approaches to strengthen progress feedback interventions include advanced systems with signaling technology, clinical problem-solving tools, and a broader spectrum of outcome and progress measures. An overview of methodological and implementation challenges is provided, as well as suggestions for addressing these issues in future studies. We conclude that while feedback has modest effects, it is a small and affordable intervention that can potentially improve outcomes in psychological interventions. Further research into mechanisms of action and effective implementation strategies is needed.

Cognitive-behavioural versus cognitive-analytic guided self-help for mild-to-moderate anxiety: a pragmatic, randomised patient preference trial.

BACKGROUND: Guided self-help (GSH) for anxiety is widely implemented in primary care services because of service efficiency gains, but there is also evidence of poor acceptability, low effectiveness and relapse. AIMS: The aim was to compare preferences for, acceptability and efficacy of cognitive-behavioural guided self-help (CBT-GSH) versus cognitive-analytic guided self-help (CAT-GSH). METHOD: This was a pragmatic, randomised, patient preference trial (Clinical trials identifier: NCT03730532). The Beck Anxiety Inventory (BAI) was the primary outcome at 8- and 24-week follow-up. Interventions were delivered competently on the telephone via structured workbooks over 6-8 (30-35 min) sessions by trained practitioners. RESULTS: A total of 271 eligible participants were included, of whom 19 (7%) accepted being randomised and 252 (93%) chose their treatment. In the preference cohort, 181 (72%) chose CAT-GSH and 71 (28%) preferred CBT-GSH. BAI outcomes in the preference and randomised cohorts did not differ at 8 weeks (-0.80, 95% confidence interval (CI) -4.52 to 2.92) or 24 weeks (0.85, 95% CI -2.87 to 4.57). After controlling for allocation method and baseline covariates, there were no differences between CAT-GSH and CBT-GSH at 8 weeks (F(1, 263) = 0.22, P = 0.639) or at 24 weeks (F(1, 263) = 0.22, P = 0.639). Mean BAI change from baseline was a reduction of 9.28 for CAT-GSH and 9.78 for CBT-GSH at 8 weeks and 12.90 for CAT-GSH and 12.43 for CBT-GSH at 24 weeks. CONCLUSIONS: Patients accessing routine primary care talking treatments prefer to choose the intervention they receive. CAT-GSH expands the treatment offer in primary care for patients with anxiety seeking a brief but analytically informed GSH solution.

Long-term psychotherapy in tertiary care: A practice-based benchmarking study.

OBJECTIVES: The literature regarding the effectiveness of long-term psychological interventions delivered in tertiary care is scarce. This study sought to quantify and evaluate outcomes delivered in a UK tertiary care psychotherapy service against equivalent service benchmarks. DESIGN: A retrospective analysis of outcomes on the Outcome Questionnaire-45 (OQ-45) over a 10-year period in a tertiary care psychotherapy service. The modalities evaluated were cognitive-behavioural, cognitive-analytic, and psychoanalytic psychotherapies. METHODS: Effectiveness was calculated at the service level and for each modality using pre-post-effect sizes and recovery rates. Benchmarking included a random-effects meta-analysis. Trajectories of change for each modality were examined using growth curve models. RESULTS: Baseline distress on the OQ-45 was higher than comparative norms (M = 102.57, SD = 22.79, N = 364). The average number of sessions was 48.68 (SD = 42.14, range = 5-335). There was a moderate pre-post-treatment effect (d = .46, 95% CI = .37-.55) which was lower than available benchmarks. The modalities differed in duration but were largely equivalent in terms of outcome. The reliable improvement rate was 29.95%, and the recovery rate was 10.16%, and change over time was best explained using a nonlinear (cubic) time trend. CONCLUSIONS: The elevated distress at baseline appears to create the conditions for relatively lengthy interventions and attenuated clinical outcomes. Suggestions are made regarding the clinical role, function, and evaluation of tertiary care psychotherapy services.

Is clinical decision making in stepped-care psychological services influenced by heuristics and biases?

BACKGROUND: The manner in which heuristics and biases influence clinical decision-making has not been fully investigated and the methods previously used have been rudimentary. AIMS: Two studies were conducted to design and test a trial-based methodology to assess the influence of heuristics and biases; specifically, with a focus on how practitioners make decisions about suitability for therapy, treatment fidelity and treatment continuation in psychological services. METHOD: Study 1 (N=12) used a qualitative design to develop two clinical vignette-based tasks that had the aim of triggering heuristics and biases during clinical decision making. Study 2 (N=133) then used a randomized crossover experimental design and involved psychological wellbeing practitioners (PWPs) working in the Improving Access to Psychological Therapies (IAPT) programme in England. Vignettes evoked heuristics (anchoring and halo effects) and biased responses away from normative decisions. Participants completed validated measures of decision-making style. The two decision-making tasks from the vignettes yielded a clinical decision score (CDS; higher scores being more consistent with normative/unbiased decisions). RESULTS: Experimental manipulations used to evoke heuristics did not significantly bias CDS. Decision-making style was not consistently associated with CDS. Clinical decisions were generally normative, although with some variability. CONCLUSIONS: Clinical decision-making can be 'noisy' (i.e. variable across practitioners and occasions), but there was little evidence that this variability was systematically influenced by anchoring and halo effects in a stepped-care context.

Risk factors for initial appointment non-attendance at Improving Access to Psychological Therapy (IAPT) services: A retrospective analysis.

BACKGROUND: Approximately 1.5 million referrals are made to Improving Access to Psychological Therapy (IAPT) services annually. However, treatment is received in less than half of cases due to ineligibility or non-attendance. The aim was to explore risk factors for non-attendance at the initial two IAPT appointments following referral. METHODS: An exploratory, retrospective analysis of referral and attendance data from five IAPT services in the North of England. Participants were 97,020 referrals received 2010-2014. Main outcome was attendance at the first two offered appointments (assessment and initial treatment). RESULTS: Based on data from two services, 66% of referrals resulted in assessment attendance. Across all five services 57% of patients who attended for assessment subsequently attended the first treatment appointment. The odds of attending an assessment appointment were more than 3 times higher for self-referrals than for GP referrals (OR 3.46, 95% CI 3.27-3.66, p < 0.001). Factors important to treatment appointment attendance following assessment were the service, referral source, presenting problem, and anxiety severity. CONCLUSION: Initial appointment non-attendance is a consistent problem for IAPT services. Specific factors that may support IAPT services to improve non-attendance rates are identified. IAPT indicators of success should take account of non-attendance at initial appointments.

Routine Outcome Monitoring (ROM) and Feedback: Research Review and Recommendations.

OBJECTIVE: To provide a research review of the components and outcomes of routine outcome monitoring (ROM) and recommendations for research and therapeutic practice. METHOD: A narrative review of the three phases of ROM - data collection, feeding back data, and adapting therapy - and an overview of patient outcomes from 11 meta-analytic studies. RESULTS: Patients support ROM when its purpose is clear and integrated within therapy. Greater frequency of data collection is more important for shorter-term therapies, and use of graphs, greater specificity of feedback, and alerts are helpful. Overall effects on patient outcomes are statistically significant (g ≈ 0.15) and increase when clinical support tools (CSTs) are used for not-on-track cases (g ≈ 0.36-0.53). Effects are additive to standard effects of psychological therapies. Organizational, personnel, and resource issues remain the greatest obstacles to the successful adoption of ROM. CONCLUSION: ROM offers a low-cost method for enhancing patient outcomes, on average resulting in an ≈ 8% advantage (success rate difference; SRD) over standard care. CSTs are particularly effective for not-on-track patients (SRD between ≈ 20% and 29%), but ROM does not work for all patients and successful implementation is a major challenge, along with securing appropriate cultural adaptations.

Predicting dropout from psychological treatment using different machine learning algorithms, resampling methods, and sample sizes.

Objective: The occurrence of dropout from psychological interventions is associated with poor treatment outcome and high health, societal and economic costs. Recently, machine learning (ML) algorithms have been tested in psychotherapy outcome research. Dropout predictions are usually limited by imbalanced datasets and the size of the sample. This paper aims to improve dropout prediction by comparing ML algorithms, sample sizes and resampling methods. Method: Twenty ML algorithms were examined in twelve subsamples (drawn from a sample of N = 49,602) using four resampling methods in comparison to the absence of resampling and to each other. Prediction accuracy was evaluated in an independent holdout dataset using the F1-Measure. Results: Resampling methods improved the performance of ML algorithms and down-sampling can be recommended, as it was the fastest method and as accurate as the other methods. For the highest mean F1-Score of .51 a minimum sample size of N = 300 was necessary. No specific algorithm or algorithm group can be recommended. Conclusion: Resampling methods could improve the accuracy of predicting dropout in psychological interventions. Down-sampling is recommended as it is the least computationally taxing method. The training sample should contain at least 300 cases.

Pragmatic randomized controlled trial of the Mind Management Skills for Life Programme as an intervention for occupational burnout in mental healthcare professionals.

BACKGROUND: Occupational burnout is highly prevalent in the mental healthcare workforce and associated with poorer job satisfaction, performance and outcomes. AIMS: To evaluate the effects of the Mind Management Skills for Life Programme on burnout and wellbeing. METHODS: N = 173 mental health nurses were recruited from the English National Health Service during the acute phase of the COVID-19 crisis. Participants were allocated to an immediate intervention or a delayed intervention control group, using a stepped wedge randomized controlled trial design. Measures of burnout (OLBI) and wellbeing (WEMWBS) were completed at four time-points: [1] baseline; [2] after the first group finished the intervention; [3] after the second group finished the intervention; and [4] six-months follow-up. RESULTS: Between-group differences were compared at each time-point using ANCOVA adjusting for baseline severity. Statistically significant effects on burnout (d = 0.60) and wellbeing (d = -0.62) were found at time-point 2, favouring the intervention relative to waitlist control. No significant differences were found at subsequent time-points, indicating that both groups improved and maintained their gains after the intervention. CONCLUSIONS: This intervention led to moderate improvements in burnout and wellbeing, despite the adverse circumstances of the COVID-19 pandemic at the time of the study.

The Effectiveness of Psychological Interventions Delivered in Routine Practice: Systematic Review and Meta-analysis.

This review presents a comprehensive evaluation of the effectiveness of routinely delivered psychological therapies across inpatient, outpatient and University-based clinics. This was a pre-registered systematic-review of studies meeting pre-specified inclusion criteria (CRD42020175235). Eligible studies were searched in three databases: MEDLINE, CINAHL and PsycInfo. Pre-post treatment (uncontrolled) effect sizes were calculated and pooled using random effects meta-analysis to generate effectiveness benchmarks. Moderator analyses were used to examine sources of heterogeneity in effect sizes. Overall, 252 studies (k = 298 samples) were identified, of which 223 (k = 263 samples) provided sufficient data for inclusion in meta-analysis. Results showed large pre-post treatment effects for depression [d = 0.96, (CI 0.88-1.04), p ≤ 0.001, k = 122], anxiety [d = 0.8 (CI 0.71-0.9), p ≤ 0.001, k = 69], and other outcomes [d = 1.01 (CI 0.93-1.09), p ≤ 0.001, k = 158]. This review provides support for the effectiveness of routinely delivered psychological therapy. Effectiveness benchmarks are supplied to support service evaluations across multiple settings.

Measurement-Based and Data-Informed Psychological Therapy.

Outcome measurement in the field of psychotherapy has developed considerably in the last decade. This review discusses key issues related to outcome measurement, modeling, and implementation of data-informed and measurement-based psychological therapy. First, an overview is provided, covering the rationale of outcome measurement by acknowledging some of the limitations of clinical judgment. Second, different models of outcome measurement are discussed, including pre-post, session-by-session, and higher-resolution intensive outcome assessments. Third, important concepts related to modeling patterns of change are addressed, including early response, dose-response, and nonlinear change. Furthermore, rational and empirical decision tools are discussed as the foundation for measurement-based therapy. Fourth, examples of clinical applications are presented, which show great promise to support the personalization of therapy and to prevent treatment failure. Finally, we build on continuous outcome measurement as the basis for a broader understanding of clinical concepts and data-driven clinical practice in the future.

Is alcohol use associated with psychological treatment attendance and clinical outcomes?

OBJECTIVES: To investigate associations between alcohol use, psychological treatment attendance, and clinical outcomes. METHODS: We analysed electronic health records for N = 7,986 patients accessing psychological treatment for common mental disorders. Data were collected for pre-treatment alcohol use (average units per week) and severity of dependence (SDS), number of therapy contacts attended, pre- and post-treatment anxiety (GAD-7), and depression (PHQ-9) symptom severity. Hierarchical regression was used to examine associations between alcohol use/dependence and post-treatment symptom severity controlling for intake severity and relevant confounders. RESULTS: After controlling for confounders, alcohol use had significant nonlinear associations with pre-treatment depression severity (R2 = .54, p < .01, cubic trend), and post-treatment anxiety (R2 = .23, p < .01, quadratic trend). Alcohol use was not significantly associated with intake anxiety, post-treatment depression or treatment duration. SDS was not significantly associated with depression severity, alcohol severity, or total contacts after controlling for confounders. CONCLUSION: Alcohol users are just as likely to engage in and benefit from evidence-based psychological treatments for depression in primary care. A nonlinear association between alcohol use and anxiety treatment outcomes indicates that light-to-moderate drinkers have some shared characteristic that favours treatment response. PRACTITIONER POINTS: Depression and anxiety problems often co-occur with alcohol use and dependence. Conventional wisdom in the field suggests that heavy alcohol users may not engage well or benefit from psychological therapies for depression and anxiety. We found no empirical support for the above assumptions in a large clinical sample. Alcohol consumption was not significantly associated with treatment attendance or depression treatment outcomes. A nonlinear association between alcohol use and anxiety outcomes suggests that moderate drinkers may have some shared characteristic that favours treatment response.

Early response as a prognostic indicator in person-centered experiential therapy for depression.

Currently, no reports exist on the phenomenon of early response in humanistic-experiential therapies. This study investigated the prognostic value of early response on posttreatment outcomes in person-centered experiential therapy (PCET) for depression within the English Improving Access to Psychological Therapies program. The design of the study was a retrospective observational cohort study. Routine clinical data were drawn from N = 3,321 patients with depression symptoms. The primary outcome was reliable and clinically significant improvement (RCSI) on the Patient Health Questionnaire-9 (PHQ-9) self-report depression measure at the end of treatment. Early response was operationalized as reliable improvement, defined as a PHQ-9 change score ≥ 6 from baseline to Session 4. Early response was examined as a predictor of RCSI using logistic regression controlling for baseline depression severity. In sensitivity analyses, therapist effects were controlled using multilevel modeling. A total of 38.7% of patients met the criterion for early response. Patients who experienced an early response to treatment were six times more likely to recover at the end of treatment compared to patients who did not have an early response. The early response effect was still evident after accounting for individual variability between therapists. However, a quarter of patients displayed a pattern of eventual response, reaching recovery at end of treatment despite not experiencing an initial improvement early in therapy. Early response to PCET is a reliable predictor of treatment outcome. Different response patterns evidenced in this study indicate that identifying subgroups of patients associated with early and eventual response could support clinical decision-making. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Psychotherapists' personality traits and their influence on treatment processes and outcomes: A scoping review.

BACKGROUND: Prior research indicates that patients' personality traits are associated with psychotherapy processes and outcomes. However, the potential relevance of therapists' personality traits is less understood. METHODS: This is a scoping review of studies investigating associations between therapists' personality traits with treatment processes and outcomes. Three databases (Scopus, PsycINFO, and Web of Science) were searched, identifying 27 eligible studies synthesized using a narrative review of key findings. RESULTS: The influence of therapists' personality traits was studied in relation to therapeutic orientation, interpersonal skills, therapist competence and skill, model fidelity, treatment outcomes, therapeutic alliance, and therapist well-being. Findings indicate that therapists' personality traits are associated with the choice of therapeutic orientation and with interpersonal skills, but there is mixed evidence about associations with clinical outcomes. CONCLUSION: Therapists' personality traits are associated with therapeutic orientation and interpersonal skills. However, it remains unclear whether therapists' personality traits influence other aspects of therapeutic processes or outcomes.