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Reflecting on DBT Assumptions about Patients and Therapy (Part 1)

“The most important thing to remember about assumptions is that they are just that—assumptions, not facts.”


Cognitive Behavioral Therapy for Borderline Personality Disorder; Marsha M. Linehan, Ph.D

This feature by Vibh Forsythe Cox, PhD is Part 1 in a series about assumptions about borderline patients and therapy. In DBT, we adhere to several assumptions that help us organize our behavior towards our clients.


I frequently field questions from people who are just learning about DBT and are working to hold the tensions that the DBT assumptions can sometimes create.  It can be helpful to remember that by definition an assumption is something that is accepted as true without proof. This hopefully ends the struggle to “prove” that there can be exceptions. There is a reason that we might want to treat our clients as though certain things are true, even without proof. In essence, these assumptions help us organize our behaviors toward our clients.

It could be said that the assumptions focus on questions where it is impossible to truly achieve certainty. By agreeing to behave according to these assumptions, we are reducing the distraction invoked by the struggle to get to certainty. By adopting these assumptions, we are not saying that we believe without doubt that these statements are true; we are agreeing that we are going to behave as though these things are true.

We can use the first assumption “Patients are doing the best they can” as an example. How you behave toward someone, and even more importantly how you assess and target their behavior, will be different when you believe that they are doing the best they can, versus if you believe they could do better and are choosing not to do their best. By referring to the first assumption, we can agree that we will approach our clients behaving as though they are doing the best that they can. 

Patients Are Doing the Best They Can

“The first philosophical position in DBT is that all people are, at any given point in time, doing the best they can. In my experience, borderline patients are usually working desperately hard at changing themselves. Often, however, there is little visible success, nor are the patients’ efforts at behavioral control particularly obvious much of the time. Because their behavior is frequently exasperating, inexplicable, and unmanageable, it is tempting to decide that the patients are not trying. At times, when asked about problematic behavior, the patients themselves will respond that they just weren’t trying. Such patients have learned the social explanation for their behavioral failures. The tendency of many therapists to tell these patients to try harder, or imply that they indeed are not trying hard enough, can be one of the patient’s most invalidating experiences in psychotherapy. This is not to say that in a well thought-out strategic approach, a therapist might not use a phrase such as this to influence a patient.”


Cognitive Behavioral Therapy for Borderline Personality Disorder; Marsha M. Linehan, Ph.D

I think one important point about this assumption is that it saves the therapist from the incredible temptation to decide that a lack of change is because of something in our client’s conscious control. I think this interpretation is tempting because it provides an escape from the responsibility of doing more careful assessment of what might be the reinforcers and punishers in the environment. It can take additional mental and emotional effort, not to mention time, to figure out what is blocking our clients from getting to their goals.  It is much easier to decide that they are not trying and hold out hope that if they just decided to do better everything would “work”.

This assumption helps us resist that temptation and keeps us doing the work to figure out what needs to change to help our clients get closer to their goals.

Through Behavioral Tech I provide training and consultation to many therapists. Sometimes, therapists will say that this assumption cannot be true because they have heard clients say “I am not really trying.” As I mentioned, there are some reasons for not getting tied up in “truth” when it comes to these assumptions. I usually respond by trying to hold up the other side of the dialectic. A client’s report isn’t actually proof. Often, our clients are people who have been told frequently throughout their lives that they are “lazy” or “not trying” or that they are “self-sabotaging”. Because of this, when we ask them about the reasons for why they did or did not do something, they may just answer with the explanations of their behavior they have received from loved ones or from former therapists.

Sometimes they have received this same messaging for decades. They may never have worked with someone who has given them an explanation based on an understanding of the transaction of biology and learning history (the bio-social model). By agreeing not to accept the “I’m not really trying” rationale, we can hold ourselves accountable for bringing a new perspective which holds more promise for identifying actionable steps toward change. With that accountability, we are more likely to do a clear behavioral assessment and we might find out, for example, that they have not been adequately reinforced for the desired behavior. Then, from a behavioral perspective, it becomes unsurprising that this behavior has not changed.

Finally, these clients have often suffered a long history of invalidation. For many this therapy is their last hope. Imagine how it would feel to describe to someone the depths of your suffering, your history of failed attempts to make life feel worth living, and to make yourself vulnerable by trying some of the new behaviors they recommend–only to hear them say that change isn’t happening because you are not really doing your best? This could be the total opposite of the client’s experience and thus would result in significant invalidation.  This experience has the potential to damage a client’s confidence that this therapist or this treatment can help them, and for some of the clients who come to this treatment, the hope that this treatment can work is the only thing standing between them and another suicide attempt.


As we learn more about the assumptions about borderline patients and therapy, we see how these assumptions give us a framework to organize our behavior toward our clients. Check back soon for part 2 from Vibh!

Vibh Forsythe Cox, PhD, serves as the Training and Development specialist for Behavioral Tech, LLC (BTECH), the training organization founded by treatment developer, Dr. Marsha Linehan. She serves on the team that creates content for BTECH’s training offerings, including the newly released Online Comprehensive Training in DBT. She provides consultation to newly forming DBT teams within the online learning platform. She works as a therapist at Cadence Child and Adolescent therapy, a DBT-Linehan Board certified DBT program in Kirkland, Washington. There, she provides DBT and other evidence-based treatments for teens and adults with emotion regulation difficulties. Dr. Forsythe Cox earned her PhD in Clinical Psychology at The Ohio State University, where her research focused on characteristics of Borderline Personality Disorder and interpersonal emotion regulation. During her time at The Ohio State University, Dr. Forsythe Cox participated in specialized training in DBT, and assisted the Director of the DBT program by providing supervision and consultation to new trainees. She was also the 2012 recipient of the Psychology Department’s Meritorious Teaching Award. Dr. Forsythe Cox has experience providing DBT in a variety of settings, including university-based research, inpatient and outpatient hospitals, forensics, and private practice facilities. She is a Clinical Instructor in the Department of Psychology at the University of Washington, where she provides individual and group supervision to doctoral psychology students in the Behavioral Research and Therapy Clinics (BRTC). Dr. Forsythe Cox has also been an invited speaker at high schools, community colleges, and the University of Washington. Dr. Forsythe Cox is licensed as a Psychologist in the state of Washington.