# The Mentalisation Switch: Therapist Reflective Capacity and Alliance Dynamics in Digital MCT+ for Bipolar Disorder—A Longitudinal Quantitative Case Series

## TL;DR

This study shows that digital therapy for bipolar disorder can reduce anxiety and harmful thinking patterns, with therapist flexibility in mentalizing being key to building a strong patient relationship.

## Contribution

The study introduces the concept of a 'mentalisation switch'—therapists' ability to shift mentalizing modes—as a novel mechanism for alliance building in digital psychotherapy.

## Key findings

- Digital MCT+ significantly reduced anxiety and improved metacognitive beliefs in individuals with bipolar I disorder.
- Therapist flexibility in mentalising (switching between automatic and controlled modes) was linked to stronger therapeutic alliance.
- Overreliance on either intuitive or reflective mentalising simultaneously may hinder relational attunement in digital therapy.

## Abstract

This study conducted a preliminary naturalistic effectiveness evaluation of Individualised Metacognitive Therapy (MCT+) delivered via videoconferencing for individuals with bipolar I disorder (BD‐I) in a real‐world clinical setting in Chile. It also explored how therapist characteristics—specifically mentalisation capacity—influence the therapeutic alliance in digital psychotherapy.

A longitudinal quantitative case series design was implemented across 14 therapist–patient dyads. Patients received 12 weekly sessions of MCT+ online. Standardised measures assessed anxiety (GAD‐7), depression (PHQ‐9), metacognitive beliefs (MCQ‐30), psychological distress (CORE‐10) and quality of life (WHOQOL‐BREF). Therapeutic alliance was tracked session‐by‐session (WAI‐S). Therapist mentalisation and attachment were evaluated at baseline (MASC‐SP, RFQ‐8, ECR‐12). Changes in outcome measures were analysed using paired t‐tests, effect sizes (Cohen's d), correlations, reliable change indices (RCI) and hierarchical linear modelling (HLM).

Across the intervention, there were significant decreases in anxiety (d = 0.64) and improvements in metacognitive beliefs (d = 0.37). Depression showed a modest improvement (d = 0.34), while changes in quality of life were negligible (d = −0.21). Hierarchical modelling indicated a significant interaction between automatic and controlled mentalisation (b = −0.45, p = 0.008), suggesting that flexible adjustment supported therapeutic alliance development. Attachment style showed no significant associations with the alliance (largest unadjusted effect: ρ = −0.54, p = 0.073; all adjusted ps > 0.99).

Digital MCT+ showed preliminary effectiveness in reducing anxiety and maladaptive metacognitive beliefs among individuals with BD‐I, with more limited effects on depression and quality of life. Importantly, therapist mentalisation flexibility—the capacity to shift between automatic and controlled modes, or the mentalisation switch—emerged as a central mechanism for alliance building and engagement in digital contexts, highlighting a key target for clinical training and future research.

Digital MCT+ may be a useful adjunctive intervention for individuals with BD‐I, particularly for reducing anxiety and maladaptive metacognitive beliefs.Therapeutic alliance in videoconferencing psychotherapy appears to be shaped not only by technique, but by therapists' capacity to flexibly adjust their mentalising stance.Early alliance building may benefit from intuitive, affectively attuned therapist responses, whereas later phases may require more explicit, reflective mentalisation to support task and goal alignment.Overreliance on both intuitive and highly self‐reflective mentalising simultaneously may hinder relational attunement in digital therapy.Training and supervision in digital psychotherapy should attend not only to therapists' reflective capacity but also to the timing and flexibility with which different mentalising modes are deployed.

Digital MCT+ may be a useful adjunctive intervention for individuals with BD‐I, particularly for reducing anxiety and maladaptive metacognitive beliefs.

Therapeutic alliance in videoconferencing psychotherapy appears to be shaped not only by technique, but by therapists' capacity to flexibly adjust their mentalising stance.

Early alliance building may benefit from intuitive, affectively attuned therapist responses, whereas later phases may require more explicit, reflective mentalisation to support task and goal alignment.

Overreliance on both intuitive and highly self‐reflective mentalising simultaneously may hinder relational attunement in digital therapy.

Training and supervision in digital psychotherapy should attend not only to therapists' reflective capacity but also to the timing and flexibility with which different mentalising modes are deployed.