What does SUDS stand for?

Subjective units of distress scale. It is a self-rating from 0 to 10, or sometimes 0 to 100, of how much distress you are experiencing at a given moment. It was introduced by the psychiatrist Joseph Wolpe in 1969.

What is a good SUDS level to start an exposure at?

Many therapists start clients on items rated around 3 to 4 out of 10. High enough that something real is happening, low enough that you can stay in it without performing the compulsion.

Should I wait for my SUDS to drop before ending an exposure?

Older habituation-based protocols often said yes, typically waiting for a drop of around half. Newer inhibitory learning approaches place less weight on the number coming down and more on whether the exposure violated what you expected to happen. Both are in use; your therapist will have a view.

The SUDS Scale: Rating Distress from 0 to 10 During Exposures

SUDS stands for the subjective units of distress scale: a 0 to 10 self-rating of how distressed you feel right now. It is used throughout [ERP](/blog/what-is-erp-exposure-response-prevention) to size up exposures, order a hierarchy, and see what actually happens to your anxiety when you do not perform the compulsion. The scale was introduced by the psychiatrist Joseph Wolpe in 1969 and has been a fixture of exposure therapy ever since.

The whole value of it is that it is subjective. There is no correct answer, no external calibration, and nothing to get right. It is your own instrument, anchored to your own experience.

The 0 to 10 anchors

Anchoring the ends and the middle to real memories, rather than to abstractions, makes the scale far more useful. A rough starting frame:

SUDS	What it tends to feel like
0	Completely calm. Asleep, or close to it.
1	Baseline. Aware of nothing in particular.
2	A background flicker. Noticeable if you look for it.
3	Uncomfortable but entirely functional. Could hold a conversation.
4	Distracting. The thought keeps pulling at your attention.
5	Clearly anxious. Body involved: chest, stomach, hands.
6	Hard to concentrate on anything else. The urge to ritualise is loud.
7	Very distressed. Focused almost entirely on making it stop.
8	Close to overwhelmed. Strong urge to leave or to perform the compulsion.
9	Overwhelmed. Feels unbearable rather than merely awful.
10	The worst distress you have ever experienced.

Then personalise it. Pick a specific memory for 3, one for 6, and one for 9, and use those as reference points. “About as bad as the week before my driving test” is a far more reliable anchor than “moderate.”

How SUDS is used in ERP

Building the hierarchy. Every item on an exposure hierarchy gets a SUDS rating, and the list is sorted by it. This is what makes the hierarchy climbable rather than an undifferentiated pile of frightening things.

Choosing where to start. Around 3 to 4 is a common starting band. Enough that the exposure is real, little enough that response prevention is achievable.

Tracking within an exposure. Rate at the start, then periodically, then at the end. The classic pattern - anxiety climbs, peaks, and comes down without you doing anything - is the single most convincing piece of evidence most people ever get. You cannot be argued into believing it. Watching your own numbers do it is different.

Tracking across repetitions. This is where the number earns its keep. Rung one on Monday might be a 7. On Friday it is a 4. Two weeks later it is a 2 and you have stopped noticing. Any single session is noise; the trend is the signal.

The number matters less than you think

Modern exposure therapy has moved away from treating a falling SUDS score as the goal. Under the inhibitory learning model developed by Craske and colleagues, exposure works by building a new association that competes with the old fear, and the thing that drives that learning is expectancy violation - the gap between what you predicted would happen and what did.

Practically, this means the more useful question at the end of an exposure is not “did my number come down?” but:

What did I expect to happen?
What actually happened?
What did I learn that I did not know before?

An exposure where your SUDS stayed at 7 the whole time, but you discovered you could tolerate a 7 for forty minutes without the ritual, is a successful exposure. That is new information and it is worth having.

Four ways SUDS goes wrong

Rating becomes a compulsion. If you are checking your number every ninety seconds, or re-rating to make sure you got it right, the tool has been captured. A few ratings per exposure is plenty.
Comparing across people. Your 6 and someone else’s 6 are unrelated quantities. The scale only means anything within one person over time.
Aspirational ratings. Recording a 4 because you feel you ought to be at a 4 by now makes the record useless, and the record is the only part that helps on a bad week.
Chasing zero. The goal of ERP is not to feel nothing near your triggers. It is to be able to live your life at whatever level of distress shows up.

A note on 0 to 100

Some clinicians use 0 to 100 rather than 0 to 10. There is no meaningful difference beyond resolution, and 0 to 10 is generally easier to use consistently in the moment. Pick one and stay with it, because switching mid-treatment destroys the comparability that makes the record valuable.

What this looks like from the inside

I resisted rating things for a long time, on the grounds that it seemed like homework invented to make therapy feel scientific. What changed my mind was going back through a month of entries on a day when I was certain I had made no progress at all.

I had rated the same exposure eleven times. The first was a 7. The last three were 2, 3, 2. I genuinely did not remember it getting easier - the improvement had been gradual enough to be invisible from the inside, and my OCD had quietly rewritten the past to match how I felt that morning.

That is the real argument for the scale. Not precision. Memory. On the days when it feels like nothing has moved, the record is the only thing in the room that is not being edited by your OCD.

Sources

Wolpe, J. (1969). The Practice of Behavior Therapy. Pergamon Press.
Craske, M. G., Treanor, M., Conway, C. C., Zbozinek, T., & Vervliet, B. (2014). Maximizing exposure therapy: An inhibitory learning approach. Behaviour Research and Therapy, 58, 10-23.
International OCD Foundation: Exposure and Response Prevention