SUDS stands for the Subjective Units of Distress Scale, a simple self-rating tool used in therapy to measure how much emotional distress you’re feeling at any given moment. You rate yourself on a scale from 0 (completely calm) to 100 (the worst distress you’ve ever felt). Therapists use it most often during anxiety treatment, trauma therapy, and other approaches where tracking your distress level in real time helps guide the session.
How the SUDS Scale Works
The scale was introduced by psychologist Joseph Wolpe in 1966. The original instructions he gave patients were straightforward: think of the worst anxiety you’ve ever experienced and call that 100, think of being absolutely calm and call that 0, then rate where you are right now. That’s essentially the entire tool. It’s a single question, answered with a number.
What makes SUDS useful is its simplicity. Unlike longer questionnaires that take minutes to fill out and measure general personality traits, SUDS captures how you feel right now, in this moment. That real-time quality is why therapists rely on it during active treatment sessions. You can give a number quickly without breaking the flow of what you’re doing in therapy.
Although it was originally designed for anxiety, SUDS is now used to measure a range of internal experiences, including anger, agitation, stress, and other forms of emotional pain.
Setting Your Personal Anchors
Before using the scale in treatment, your therapist will help you “anchor” it to your own experiences. You’ll identify specific memories that represent a 0, a 50, and a 100 for you personally. These anchors should be events you actually lived through, not hypothetical scenarios, and they shouldn’t be related to whatever you’re in treatment for. The point is to give you reliable reference points so your ratings stay consistent from session to session.
This is entirely subjective by design. There’s no “correct” rating for any situation. A crowded elevator might be a 70 for one person and a 20 for another. The scale measures your distress, calibrated to your own experience.
Where SUDS Is Used in Therapy
SUDS shows up most frequently in exposure-based therapies, where you gradually face situations or memories that cause distress. It plays a central role in several well-established treatments.
In prolonged exposure therapy for PTSD, therapists ask for your SUDS rating before you begin recounting a traumatic memory and then every five minutes during the retelling. You say a number and keep going without stopping. This gives the therapist a map of your distress throughout the session. Early assignments typically target situations in the 40 to 50 range (moderate distress) before working up to harder ones.
In exposure and response prevention for OCD, therapists use SUDS to pace your exposures and decide when you’re ready to move to the next level. In EMDR (eye movement desensitization and reprocessing), SUDS ratings track how much a traumatic memory still disturbs you before, during, and after processing.
Across all these approaches, therapists record three numbers for each exercise: your distress before you started, the peak distress during the exercise, and your distress when you finished.
What Your Scores Should Do Over Time
The pattern therapists look for unfolds on two levels. Within a single session, your distress typically rises when you confront something difficult, then gradually comes back down as you stay with it. If you start an exposure at 100 and end at 85, that’s already the beginning of your nervous system learning that the situation is survivable.
The more important pattern happens between sessions. Over the course of treatment, the same situation that triggered a peak of 90 in your first session might only reach 60 a few weeks later. This reduction from one session to the next is the stronger predictor of overall improvement. Research on PTSD treatment has consistently found that this between-session drop in distress ratings predicts how much symptoms improve overall, while the amount distress drops within any single session is less reliably linked to outcomes.
In practical terms, this means a tough session where your distress stays high the whole time isn’t a failure. What matters more is whether the same material feels less intense the next time you face it.
How Reliable Is a Single Number?
A reasonable question about SUDS is whether a quick self-reported number actually means anything clinically. Research suggests it does, though with some limits. SUDS ratings correlate meaningfully with established measures of distress. In one study of EMDR patients at a trauma clinic, baseline SUDS scores correlated with both depression and state anxiety measures. SUDS also showed concurrent validity with standardized symptom questionnaires, with correlation values around 0.46 to 0.50.
For tracking progress, SUDS ratings at the end of therapy sessions predicted clinician-rated improvement, and that predictive relationship grew stronger as treatment progressed, rising from a correlation of 0.32 after the first session to 0.61 by the third. Importantly, SUDS scores weren’t influenced by age, education, or income, which supports the idea that the scale measures distress itself rather than something else about the person.
The scale isn’t a diagnostic tool or a replacement for comprehensive assessment. It’s a quick, in-the-moment check-in that gives both you and your therapist a shared language for something that’s otherwise hard to communicate: exactly how bad something feels right now, expressed as a number you can track over time.
What a Typical SUDS Check-In Looks Like
If your therapist uses SUDS, the experience is simple. They’ll ask something like “What’s your number right now?” or “Give me your SUDS.” You respond with a number between 0 and 100. There’s no lengthy questionnaire, no right or wrong answer. During an exposure exercise, you might be asked every few minutes. During a regular therapy conversation, your therapist might check in once or twice.
You’ll also use the scale on your own between sessions. Homework assignments for exposure therapy typically involve facing a feared situation in real life, then recording your SUDS before, during, and after. These logs help your therapist adjust the pace of treatment. If your between-session ratings are dropping steadily, you may be ready for more challenging exposures. If they’re stuck, your therapist can troubleshoot what’s getting in the way.