Schema Therapy for Cluster C Personality Disorders: What the QUEST Trial Changes for Clinicians

Elena, a teaching case I created for this article rather than a real client, eats lunch in her car. Six years now, level three of the hospital garage, engine off, a sleeve of crackers on the passenger seat. Two courses of therapy sit behind her, and she can explain her avoidance more precisely than some of the clinicians who treated her. She still eats in the car. Insight was never what she was missing. Clients like her are the reason the newest trial of schema therapy for cluster C personality disorders deserves a careful read.

In October 2026, the Dutch QUEST trial reported that 30 sessions of group schema therapy held level with 50 individual sessions. Both formats beat specialized usual care at one year. Then came the two-year follow-up, with a result that changes how I would describe what this treatment offers.

I’m Travis Atkinson, founder of the Schema Therapy Training Center of New York (STTC). Our ISST-approved certification programs in individual schema therapy (ST-I) and couples schema therapy (ST-C) run live online. This is a trainer’s reading of QUEST, told partly through Elena, a teaching case who stands in for a client you may already be seeing on Tuesday afternoons. It’s written for mental health clinicians who treat avoidance, perfectionism, or dependence. You’ll get the findings, the limits, and what the evidence means for training.

Short answer: Does schema therapy work for cluster C personality disorders? Yes. At one year it reduced disorder severity more than specialized usual care, in group and individual formats alike.

TL;DR: Avoidant, dependent, and obsessive-compulsive presentations fill outpatient caseloads, and skills work alone rarely shifts them. QUEST shows one bounded year of schema therapy bringing relief sooner than specialized usual care and keeping more patients in treatment. STTC teaches the mode work behind it.

Key takeaways

• The clinical problem: Cluster C patients often cycle through several treatments, gaining insight without lasting change.
• Why it is hard: Avoidance is self-protection. It soothes fear today and deepens it tomorrow.
• How schema therapy reframes it: Modes become the target, and new emotional experience in the room, through imagery rescripting, chairwork, and limited reparenting, does the changing.
• Where training fits: Practiced skill, not familiarity with the model, is what therapists most need to build.

What did the QUEST trial find about schema therapy for cluster C personality disorders?

QUEST found that schema therapy, in group or individual form, reduced cluster C personality disorder severity more than specialized usual care after one year. The effects were small to moderate: d = 0.41 for individual schema therapy and d = 0.33 for group. Raters were blind to treatment.

The trial randomized 369 psychiatric outpatients across 10 Dutch mental health centers. Researchers at the University of Amsterdam led it, with Arnoud Arntz and Nathan Bachrach as principal investigators, and the results appeared in BMJ Mental Health in October 2026. Recruitment ran from March 2021 to June 2023, and follow-up ended in April 2025.

Read the sample description and Elena could be sitting in it. Average age 37, about two-thirds women. Avoidant personality disorder was the main diagnosis for 77%, and most of the rest carried obsessive-compulsive personality disorder, with dependent presentations making up a smaller share. These were not exotic research cases. They were the people who skip the office party and apologize for taking up your time.

What did each arm of the trial receive, and how did it do?

The three arms differed sharply in dose, structure, and staying power:

	Individual schema therapy	Group schema therapy	Specialized usual care
Treatment sessions	50 sessions, twice weekly at first, then tapering	30 weekly 90-minute sessions, two therapists, five to nine patients, four monthly boosters	Personality disorder departments, no fixed end
Severity at one year vs. usual care	Greater reduction, d = 0.41	Greater reduction, d = 0.33	Improved, more slowly
Still in treatment at one year	92.7%	84.9%	78.2%
Two years	Difference no longer significant (d = 0.23)	Difference no longer significant (d = 0.12)	Large improvement

What this means for therapists: Both schema formats produced earlier improvement than specialized usual care. QUEST does not show long-term superiority, and it does not show individual schema therapy beating group on the primary outcome.

Did schema therapy change personality functioning or only symptoms?

The gains reached beyond symptom counts. Both schema formats produced earlier improvement in self-esteem, quality of life, happiness, and sleep, the parts of a life that symptom checklists tend to miss. For Elena, that list comes down to plain things: a full night’s sleep, a Saturday not spent recovering from the week. Individual therapy outperformed the group format on only one measure, general quality of life at one year, and its patients reported the highest satisfaction with care.

Retention tells its own story. At one year, only the individual therapy difference reached statistical significance. By two years, usual care retention had fallen to 72%, and both schema formats kept more patients. Cluster C patients rarely storm out of treatment. They cancel politely, stop rescheduling, and disappear from the caseload without anyone noticing the exact week it happened.

Why does it matter that 30 group sessions held level with 50 individual sessions?

It matters because group schema therapy delivered comparable outcomes for a fraction of the therapist time. Do the arithmetic. Two therapists running 30 sessions of 90 minutes spend about 90 therapist-hours per group, or roughly 10 to 18 hours per patient before boosters.

The trial’s protocol authors projected more than a 50% cut in therapist time compared with individual schema therapy. A clinic director with a waitlist that runs into next year will stop reading there. Clinicians choosing where to invest training hours should keep going, because the more useful point for them sits in what the two formats share.

A careful reading still matters. Group and individual differed by d = 0.08 (p = .57), and “no significant difference” is not the same claim as demonstrated equivalence. Individual therapy also kept a small edge on retention, satisfaction, and one quality-of-life measure. Still, two formats landing this close is a meaningful signal. Same active ingredients, different route.

What happened to schema therapy for cluster C personality disorders at two years?

By two years, the between-treatment differences were no longer statistically significant. All three arms showed large improvements. Usual care, the slow starter, had caught up.

Nobody knows exactly why. Specialized usual care often ran longer, and its patients received more sessions in year two, yet controlling for those extra sessions did not change the findings. QUEST’s authors also raise the possibility that contemporary specialized treatment has improved since earlier trials. The study cannot settle it.

What, then, did schema therapy offer during that first year? Earlier improvement on severity, self-esteem, quality of life, happiness, and sleep. A treatment with an end date, and retention too, with 92.7% of individual patients still engaged at twelve months.

The authors flag further limits. When they reran the primary analysis without outliers and influential cases, the group effect fell to d = 0.27 and lost significance (p = .06), while the individual result held. Part of the trial ran during COVID-19, repeated assessments led some participants to leave the study, and every site was a Dutch specialist service. Generalize with care.

What are cluster C personality disorders, and why have they been understudied?

Cluster C personality disorders form the anxious-fearful group in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders: avoidant, dependent, and obsessive-compulsive personality disorder. Three diagnoses, one engine. Chronic fear drives each of them, and coping organizes itself around avoidance or control.

The DSM sorts personality disorders into three clusters: odd-eccentric (A), dramatic-erratic (B), and anxious-fearful (C). Research attention has flowed toward cluster B, especially borderline personality disorder, where self-harm and crisis make the stakes visible to everyone in the building. The patient in crisis gets the case conference, and the one who cancels politely gets a discharge letter. Cluster C patients often come in for depression or social anxiety. They leave as quietly as they arrived.

The numbers argue for more attention. Cluster C presentations account for up to 30% of patients in mental health services. In clinical samples, prevalence estimates range from about 10.5% for obsessive-compulsive personality disorder to 24.6% for avoidant personality disorder. Most have been in therapy before. In one study of individual schema therapy, patients had already averaged 2.33 previous treatments spanning 2.67 years. Elena, with two earlier rounds of therapy, sits right at the norm.

How do the three cluster C personality disorders differ?

Each presentation organizes fear differently, and each has a recognizable face in the waiting room:

• Avoidant personality disorder: pervasive fear of rejection and hypersensitivity to criticism. The DSM diagnostic criteria include viewing oneself as socially inept, personally unappealing, or inferior. Commonly cited population estimates sit around 1.5% to 2.5%, and comorbid social anxiety disorder is frequent. Elena lives here.
• Dependent personality disorder: a pervasive need to be cared for, with submissive behavior and intense fear of separation. Everyday decisions get handed to others, down to texting a sister before choosing a paint color.
• Obsessive-compulsive personality disorder: perfectionism, rigidity, and preoccupation with order at the expense of flexibility and closeness. Think of the manager who rewrites the team’s report at 1 a.m. because it still isn’t right. It is a separate diagnosis from OCD.

Personality traits like these usually take shape in childhood and adolescence, though a diagnosis generally waits until after age 18. Several factors feed them, from temperament to childhood experiences of criticism or rejection. Untreated, the patterns tend to last.

How does avoidant personality disorder differ from social anxiety disorder?

The two overlap heavily, and many patients meet diagnostic criteria for both. Social anxiety disorder, once called social phobia, centers on fear of particular social situations: speaking in meetings, eating in public, being watched. Avoidant personality disorder runs wider. The fear attaches to the self rather than the situation, so low self-esteem and the expectation of rejection follow the patient into relationships, work, and eventually the therapy room.

A socially anxious client dreads giving the toast at a wedding. The client with avoidant personality disorder dreads being found out as uninteresting, whether she is giving the toast or refilling water glasses in the kitchen.

That distinction shapes treatment. Exposure work can shrink social anxiety without touching the belief underneath it. In avoidant personality disorder, the Defectiveness/Shame and Social Isolation/Alienation schemas tend to outlast skills gains, which is where schema work earns its place.

How does schema therapy conceptualize avoidant personality disorder?

Schema therapy treats avoidant personality disorder as a mode problem rather than a skills deficit. Elena talks easily with pharmacy customers all day, so she isn’t unskilled. She is stuck. A self-protective state switches on the moment she feels exposed, and the coping pattern that follows keeps the underlying schemas intact.

Dr. Jeffrey Young developed schema therapy as an integrative model, drawing on cognitive-behavioral, psychodynamic, gestalt, and object relations principles. Its core unit is the early maladaptive schema, an enduring pattern of memories, emotions, and beliefs grown from unmet childhood needs. Those needs include secure attachment, autonomy, and the freedom to express emotions. In avoidant presentations, three schemas tend to sit near the center: Defectiveness/Shame, Social Isolation/Alienation, and Emotional Deprivation. Coping runs in three broad directions: surrender, avoidance, overcompensation.

Avoidance is the trap. It lowers anxiety in the moment and strengthens the fear over time, a negative reinforcement loop that Young and colleagues describe in the original model. Every skipped party brings a small relief and a small confirmation. What never gets touched is the longing underneath, to be wanted at the table.

That avoidance reaches inward too. Many patients with avoidant PD show impaired emotional awareness, so distress surfaces as numbness rather than a feeling they can name.

How avoidance keeps a schema alive

Where schema therapy breaks in

At the schema

Imagery rescripting reaches the memory underneath

At the mode

Chairwork and limited reparenting

At the response

Behavioral pattern breaking

Which schema modes matter most in schema therapy for cluster C personality disorders?

Research using an expanded version of the Schema Mode Inventory mapped distinct mode profiles for specific disorders within cluster C (Bamelis and colleagues, 2011). I co-authored the Schema Mode Inventory, so I come to these profiles with some bias in how useful I find them. They hand a therapist a working map before the first imagery session.

• Avoidant personality disorder: Lonely Child, Abandoned Child, Compliant Surrenderer, Detached Protector, and Avoidant Protector.
• Dependent personality disorder: Abandoned Child, Dependent Child, Compliant Surrenderer, Punitive Critic, and a weak Healthy Adult.
• Obsessive-compulsive personality disorder: Perfectionistic Over-Controller and Demanding Critic.

A missing mode matters as much as the present ones. In cluster C, it’s usually anger. The Cambridge Guide to Schema Therapy treats the Angry Child mode as a natural source of strength for these clients. Shutting anger down entirely also shuts down assertiveness, so therapists place anger on the mode map even when the client insists they never feel it.

What does schema therapy for cluster C personality disorders look like in a session?

Elena is 38, a hospital pharmacist, and the garage is her secret. Colleagues still invite her out. She has errands. Like many cluster C clients, she describes emotional disconnection more than open distress, a kind of numbness where feelings should be. In the assessment she calls herself “the boring one people put up with.” Asked what she wants from therapy, she pauses, then hands the question back: “Whatever you think is best” (Compliant Surrenderer).

Four weeks in, the therapist asks her to bring up an image of the staff lunchroom. Elena goes flat, her voice drops, and she reports feeling nothing about it (Detached Protector). Her therapist doesn’t push past the numbness. The therapist slows down, softens her voice, and stays with it: “Something goes quiet in you when we go there. Can we stay with that quiet for a moment?”

Staying with it, slowly, is what opens the door. Imagery rescripting later reaches the softer hurt underneath: a twelve-year-old at a family dinner, laughed at for asking a question and told she was too sensitive. Her brother’s laugh is the detail she remembers most. The therapist steps into the image and speaks to the family at that table: “That was a good question. She’s not too sensitive, and nobody gets to laugh at her for asking.” Elena cries, for the first time in session. The feeling she has protected herself from for decades finally has somewhere safe to land.

In a group, the turning point might arrive differently. A fellow member criticizes one of the therapists, and Elena’s jaw tightens. Asked what she noticed, she says quietly, “I think that was unfair.” For a woman who has never disagreed out loud, that sentence is a new step in an old dance. The Healthy Adult is speaking, with the Angry Child’s energy behind it, and nobody leaves.

What happens inside group schema therapy for cluster C personality disorders?

Group schema therapy for cluster C personality disorders uses the group itself as an intervention, which suits avoidant PD in particular. Patients whose core fear is being seen and judged sit with four to eight other people who share that fear. The exposure is built in.

QUEST’s group protocol ran weekly 90-minute sessions with two therapists. According to the trial registry, groups were semi-closed, with composition changing every 10 sessions. Newcomers kept arriving. That rolling structure lets a newer member like Elena watch someone ten sessions ahead of her say no to the group and survive it, something an individual room can’t offer.

Two therapists also change the mechanics of mode work. One can stay with a patient in chairwork, giving voice to the Punitive Critic and then confronting it, while the other tracks the room. Group imagery rescripting lets several members work on a shared theme at once. Limited reparenting extends outward too, as peers begin offering each other the warmth, validation, and responsiveness the therapists model.

Avoidance shows up in the group, which is the point. Take the patient who never speaks first. She is in the same Avoidant Protector state she lives in outside the group, only now it is visible and workable. Bachrach and Arntz’s published case study on avoidant personality disorder illustrates how the cluster C group protocol breaks through persistent avoidance and control.

How does QUEST fit into the wider research on schema therapy for cluster C personality disorders?

QUEST adds the first large randomized test of group schema therapy to an evidence base already established for individual schema therapy in cluster C. These treatment studies point one way. Schema therapy is an effective treatment option for these presentations, and group work now stands on firmer ground.

• Bamelis and colleagues (2014): This multicenter RCT randomized 323 patients with cluster C, paranoid, histrionic, or narcissistic personality disorder, and 90% had cluster C diagnoses. Fifty sessions of individual schema therapy outperformed treatment as usual on recovery, meaning patients no longer met diagnostic criteria. Dropout was also lower (25.8% versus 37.8%).
• Wibbelink and colleagues (2023): An open multicenter pilot of group schema therapy treated 137 cluster C patients. It reported medium to large effect sizes after two years and a treatment dropout rate of 11.7% (Clin Psychol Psychother).
• Tracy, Penney, and Norton (2024): This systematic review of 14 studies found strong support for group schema therapy reducing cluster B and C symptoms, particularly in borderline and avoidant personality disorder. Many studies had no control condition, and risk of bias was moderate. The authors see group schema therapy as a potential answer to the long waits and high costs of individual treatment.
• Trials underway: The I-FORCE protocol compares individual schema therapy with short-term psychodynamic supportive psychotherapy and affect phobia therapy in 264 cluster C patients. The G-FORCE protocol compares two schema group formats with psychodynamic group therapy in 290 patients.

Schema therapy research in borderline personality disorder remains larger, a story told in our BPD research overview. Cluster C fills the private practice week. The I-FORCE authors also note schema therapy’s clinical effectiveness for anxiety and depression, which often bring cluster C patients through the door in the first place.

One caution belongs here. QUEST’s own economic evaluation is still under way, so firm cost-effectiveness claims for the group format should wait for that paper.

What does QUEST mean for schema therapy training?

QUEST points toward one need above the rest: more clinicians who can do schema mode work well, whatever format they practice. Services want group schema therapy because it treats more people with fewer therapists. It only works with skilled ones.

A schema group is only as strong as its two therapists’ individual mode work. Running chairwork while five people watch, reading a Detached Protector across a video grid, repairing a rupture between two members: all of it draws on skills built one to one. I ran therapy groups for more than 25 years as a certified group psychotherapist. My strong impression is that clinicians who start with groups before they can map modes individually end up running psychoeducation classes. Good ones, sometimes.

Formal group schema therapy has its own protocols and its own training. STTC doesn’t teach it. We teach the individual and couples applications, which is where most clinicians start and where QUEST’s strongest result sits.

How therapists learn matters too. Change in this work happens when a feeling is slowed down, deepened, and met in the room, and that takes practice to do well. The Bamelis trial holds a quiet lesson about it. Its first cohort of schema therapists trained mainly through lectures. The second trained mainly through exercises, and their patients did better, which led the authors to conclude that exercise-based training was superior. That finding is consistent with how STTC teaches, with imagery rescripting and chairwork practiced live in small breakout groups. It doesn’t establish anything about our program in particular.

What does QUEST change for clinicians in private practice?

QUEST supports schema therapy as a bounded treatment for presentations most private practice clinicians already see. A beginning, a middle, an end. You don’t need a personality disorder caseload for any of this to apply.

Many skilled clinicians bring a reasonable belief into cases like Elena’s: a clearer explanation, or a better skill, will eventually move her. She has heard the explanations. Every one of them makes sense to her, and then she drives back to the garage. Insight rarely shifts a pattern held in place by emotion. A new emotional experience, felt in the room with someone who stays, usually does. The table shows where a schema formulation changes the work.

A therapist encounters…	A schema formulation asks…	Schema therapy adds…
Chronic avoidance despite insight	What is the person protecting themselves from feeling?	Coping modes, vulnerable child states, experiential work
Perfectionism and rigidity	What happens emotionally when a standard is missed?	Demanding/Punitive modes, overcontrol, unmet needs
Reassurance seeking or constant accommodation	What feels dangerous about disagreeing or acting alone?	Surrender patterns, attachment fears, autonomy needs
“I know why I do it, but I still do it.”	Which part understands the pattern, and which mode takes over when it’s triggered?	Mode work, imagery rescripting, chairwork, behavioral pattern breaking

Framing matters too. Cluster C patients often expect therapy to drift, because earlier treatment did. I find that naming a time frame up front, with room for booster sessions later, gives the Compliant Surrenderer less space to hand the work back to the therapist.

Which patients do better in group or individual schema therapy?

Nobody can say yet. The QUEST protocol planned analyses of which patient characteristics predict a better response to each format, including childhood trauma, autistic features, and introversion. Its research team also plans a tool to help patients and clinicians match treatment to the person. Until that evidence appears, format choice remains a clinical judgment.

What does cluster C research mean for couples therapists?

QUEST did not study couples, and nothing here should be read as couples outcome data. Even so, cluster C patterns turn up constantly in intimate relationships, and couples schema therapists meet these modes daily.

Owen and Marisol (a couple I created for this article as a teaching case, not real clients) have the same fight every few weeks, and it usually starts at the dishwasher. Marisol reloads it after Owen has finished, because the glasses belong on the top rack and the bowls face inward (Perfectionistic Over-Controller). Owen says nothing. He goes numb inside, gone from the conversation while still standing in the kitchen (Detached Protector). Marisol feels the silence as rejection, and her criticism sharpens. Underneath it is a protest, something close to “Do I matter to you?” Owen’s withdrawal is self-protection from the sense that he is failing her again.

A partner with a dependent profile adds a different strand, keeping the peace for years (Compliant Surrenderer) until resentment leaks out sideways. Each partner’s mode activates the other’s schemas. The cycle locks, and neither partner is the villain. That cycle is the common enemy.

As a co-developer of Schema Therapy for Couples, I find these loops loosen when both partners can name the mode in real time. Then they can reach for each other from underneath it. Every couple is asking, in one form or another, whether the other will be accessible and responsive when it counts. My goal is not to make the Vulnerable Child disappear. Quite the opposite. A healthy relationship gives that mode more room, alongside the Healthy Adult and the Happy Child, which together form what I call the healthy mode triad.

Once a clinician can see schemas and modes in one person, couples work raises the next question: what happens when two people’s modes activate each other? Our couples schema therapy certification training works in that territory. Clinicians trained in Emotionally Focused Therapy for Couples or the Gottman Method will recognize these dynamics. Mode work and attachment-focused work integrate rather than compete, and they do so from the first session, with nothing to unlearn.

How does STTC training prepare clinicians for schema therapy for cluster C personality disorders?

ST-I, our individual schema therapy certification training, teaches the model QUEST’s individual arm tested: mode mapping, imagery rescripting, chairwork, limited reparenting, and empathic confrontation. It runs 14 live online sessions totaling 42 coursework hours, above the 40 that ISST requires. ST-C runs 11 sessions totaling 33 hours. ISST requires 30.

Every session blends focused teaching, demonstration, and experiential practice. Live sessions are recorded, except the experiential exercises. Cohorts are capped at 20 and draw clinicians from many countries, which keeps the room from turning into an echo of one training culture. Eligibility: a master’s degree or higher and current licensure to practice psychotherapy.

Certification decisions belong to the International Society of Schema Therapy, not to STTC. Our coursework fulfills the coursework component of ISST certification. ISST certification also requires educational consultations, also known as supervision, which are offered separately from coursework and at additional cost.

My own lineage runs back to 1994, when I began training directly with Dr. Jeffrey Young. I was one of the original founders of the International Society of Schema Therapy, and I hold its Honorary Lifetime Membership. That history shapes the teaching. Close to the original schema model, open to where the field has gone.

Tuition is set regionally using World Bank country tiers, with installment plans available. Review the tuition and payment options.

Back to the garage. Elena’s story, as I wrote it, doesn’t end with a cure. It ends on an ordinary Tuesday, with a tray in her hands and an empty chair at the end of a table she has walked past for six years. She sits down. Someone asks about her weekend, and she answers with more than one word. She reached, and someone responded. QUEST suggests change like that can arrive within a year. Whether it arrives for your clients depends partly on what you can do when the Detached Protector walks into your office.

Frequently asked questions about schema therapy for cluster C personality disorders

Is schema therapy for cluster C personality disorders effective?

Yes. Two large Dutch randomized trials now support it. Bamelis and colleagues (2014) found individual schema therapy outperformed treatment as usual on recovery. QUEST (2026) found individual (d = 0.41) and group (d = 0.33) formats both reduced disorder severity more than specialized usual care at one year.

Does QUEST show schema therapy is better than other treatments for cluster C?

Not over the long term. By two years, the between-treatment differences were no longer statistically significant. What QUEST does support is earlier improvement on severity, self-esteem, and sleep inside a bounded year, along with better retention than specialized usual care.

Is individual or group schema therapy more effective?

In QUEST, the two did not differ significantly on disorder severity (d = 0.08). Individual therapy kept an edge on retention and satisfaction, and its effect held up better when outliers were removed. A null difference is still not demonstrated equivalence.

What does QUEST mean for therapists treating avoidant personality disorder or OCPD?

It strengthens the case for schema work with presentations most clinicians already carry: chronic avoidance, shame, perfectionism, dependence. Avoidant personality disorder was the main diagnosis for 77% of the sample, and most of the rest had OCPD. No personality disorder specialty required.

What is the best treatment for avoidant personality disorder?

No treatment has a strong evidence base for avoidant personality disorder yet. A 2023 review counted only four small randomized trials focused on it. The largest schema therapy trials studied cluster C more broadly, yet avoidant PD was the main diagnosis for about half of Bamelis and colleagues’ sample (2014) and 77% of QUEST’s (2026).

How is schema therapy treatment different from CBT for cluster C PD?

CBT targets the thoughts and behaviors that keep avoidance going. Schema therapy treatment works a level deeper, with the modes and unmet childhood needs underneath. Imagery rescripting and chairwork carry much of the change. In my experience, CBT-trained clinicians find the two fit well together.

Which schema therapy skills matter most with avoidance, perfectionism, or overcontrol?

Mode mapping comes first, so you know which state is in the room. Imagery rescripting reaches the memories underneath the shame. Chairwork gives the Demanding and Punitive Critic modes a chair of their own, where they can be confronted.

How much training does a therapist need to use schema therapy competently?

ISST certification sets the standard. ST-I provides 42 coursework hours toward the 40-hour individual requirement, and ST-C provides 33 toward the 30-hour couples requirement. Educational consultations, also known as supervision, are offered separately from coursework and at additional cost, and ISST makes the final certification decision.

Does STTC training prepare me to run group schema therapy?

No. STTC teaches individual and couples schema therapy. Formal group schema therapy, like the protocol QUEST tested, has its own training.

Are STTC training sessions recorded?

Yes. Live sessions are recorded, except the experiential exercises. Recordings help with review, but watching them in place of attending live does not count toward ISST certification.

Can international clinicians join an STTC cohort?

Yes. Cohorts meet live online and bring together clinicians from many countries. Tuition follows regional tiers, with installment plans available.

What is the refund policy?

STTC does not offer full refunds under any circumstances. A one-year deferral is available.

Is STTC’s individual schema therapy training the right next step?

If QUEST matched what you already see with avoidant, dependent, or perfectionistic clients, the next step is learning to work at the level of modes. Chances are an Elena is already on your caseload. ST-I is where that work starts.

References

• Bachrach, N., & Arntz, A. (2021). Group schema therapy for patients with cluster-C personality disorders: A case study on avoidant personality disorder. Journal of Clinical Psychology, 77(5), 1233–1248.
• Bamelis, L. L. M., Renner, F., Heidkamp, D., & Arntz, A. (2011). Extended schema mode conceptualizations for specific personality disorders: An empirical study. Journal of Personality Disorders, 25(1), 41–58.
• Bamelis, L. L. M., Evers, S. M. A. A., Spinhoven, P., & Arntz, A. (2014). Results of a multicenter randomized controlled trial of the clinical effectiveness of schema therapy for personality disorders. American Journal of Psychiatry, 171(3), 305–322.
• Groot, I. Z., Venhuizen, A.-S. S. M., Bachrach, N., et al. (2022). Design of an RCT on cost-effectiveness of group schema therapy versus individual schema therapy for patients with cluster-C personality disorder: The QUEST-CLC study protocol. BMC Psychiatry, 22, 637.
• Psychreg News Team. (2026, October 30). Schema therapy eases anxious personality disorders faster than specialised usual care, Dutch trial finds. Psychreg.
• QUEST trial results. (2026). BMJ Mental Health, 29(1), e302929.
• Tracy, M., Penney, E., & Norton, A. R. (2024). Group schema therapy for personality disorders: Systematic review, research agenda and treatment implications. Psychotherapy Research.
• Wilberg, T., Pedersen, G., Bremer, K., Johansen, M. S., & Kvarstein, E. H. (2023). Combined group and individual therapy for patients with avoidant personality disorder: A pilot study. Frontiers in Psychiatry, 14, 1181686.
• Wibbelink, C. J. M., Venhuizen, A.-S. S. M., Grasman, R. P. P. P., et al. (2023). Group schema therapy for cluster-C personality disorders: A multicentre open pilot study. Clinical Psychology & Psychotherapy, 30(6), 1279–1302.