SUDS scale in EMDR: how to rate distress 0 to 10

The SUD scale (Subjective Units of Disturbance, sometimes called SUDS) rates how distressing something feels right now, from 0 (completely calm) to 10 (the worst distress you can imagine). EMDR therapists use it to set a baseline before reprocessing and recheck it after each round of bilateral stimulation, watching for it to drop toward 0 or 1.

You’re about to start a round of bilateral stimulation, or you’re partway through an EMDR session, and someone, a therapist, an app, or just you, asks how distressed you feel right now, zero to ten. It’s a strange question to answer cold. Do you round up, compare it to yesterday, or measure it against the worst day of your life? The SUD scale only works once you know how to actually use it, not just what the numbers mean.

What do “SUD” and “SUDS” actually mean?

SUD stands for Subjective Unit of Disturbance, sometimes written Subjective Unit of Distress. Psychiatrist Joseph Wolpe coined the term in his 1969 book The Practice of Behavior Therapy, and used “sud” as the actual unit, the way “degree” is a unit on a thermometer. SUDS is the plural: the name for the scale itself.

Most people, including EMDR therapists, use “SUD scale” and “SUDS scale” interchangeably, and so does this guide. For the short definition, see our glossary entry on the SUDS scale.

Where did the 0-to-10 scale come from?

Wolpe’s original scale ran 0 to 100. His method: picture the worst anxiety you’ve ever felt, or can imagine feeling, and call it 100. Picture total calm and call it 0. Then rate where you actually are right now, based on those two markers.

A 2008 study in the Journal of EMDR Practice and Research notes that Wolpe later described a shorter version running 0 to 10, the same range EMDR therapists use today. EMDR’s own standard protocol, built by Francine Shapiro, adopted that compact scale, and it’s stayed the field’s default ever since.

Why rate a number instead of just saying “stressed” or “awful”?

Words like “stressed,” “awful,” or “fine” don’t compare well across time. What felt “awful” on a good week might be what you’d call a 4 on a genuinely hard one. A number gives you, and in therapy your therapist, a shared, comparable unit: an 8 today means roughly the same thing as an 8 last month, as long as you’re using the same personal anchors.

That comparability, not precision for its own sake, is the whole point of the scale. It’s the same reason a nurse asks for pain on a 0-to-10 scale instead of asking whether it “hurts a lot.” A number can be tracked. A mood word mostly can’t.

How do you actually come up with a number?

Most people freeze the first time they’re asked, because they’re trying to rate distress in the abstract. Wolpe’s original instructions work better: set your two anchors first. Think of an actual moment you’d call a 0, fully calm, and an actual moment you’d call a 10, the worst you’ve ever felt or can imagine feeling. Once both are real memories instead of vague ideas, everything else you rate has somewhere to sit between them.

A few habits make the number more honest:

• Rate right now, not back then. If you’re thinking about something that happened years ago, rate how it feels to bring it to mind today, not how intense it was at the time. Those are often different numbers.
• Don’t chase precision. A whole number is enough; you’re not measuring anything to a decimal point. If you’re stuck between two, either one is fine.
• Go with the first number, not the tidy one. Your instinctive answer is usually more accurate than the one you talk yourself into after a few seconds of “should I be more upset than this?”
• Check your body, not just your thoughts. A tight chest, a clenched jaw, or a knot in your stomach is often more honest than what you’re telling yourself the number should be. If your body says 7 and your head says “I’m fine, it’s a 3,” the body is usually closer to true.

What do the different numbers roughly mean?

There’s no official chart, and that’s on purpose. A 2025 methods review in Clinics and Practice found that SUDS is defined and used inconsistently across studies, and cautioned against treating it as a precise instrument. Your 6 and someone else’s 6 aren’t the same feeling.

Still, most people find it easier to start with rough zones and adjust them to fit their own experience:

Range	What it tends to feel like
0 to 2	Calm, or a mild background awareness. Easy to think clearly.
3 to 5	Noticeable and a little uncomfortable, but you can still function, focus, hold a conversation.
6 to 7	Strong and hard to ignore. Concentration gets harder; the feeling wants your attention.
8 to 10	Overwhelming. Hard to think past, hard to reason your way out of in the moment.

Use this as a starting sketch, not a rulebook. The number that matters is the one that’s true for you, right now, compared with your own 0 and your own 10.

How does EMDR use your SUD rating?

In full EMDR therapy, your SUD rating does two jobs. Per EMDRIA’s breakdown of EMDR’s eight phases, the Assessment phase has you rate a target memory before any bilateral stimulation starts, which sets a baseline. Then, in the Desensitization phase, your therapist checks your SUD again after every set of eye movements, tones, or taps, and keeps going until it settles near 0, sometimes 1 if a small, realistic amount of disturbance still makes sense given the facts.

A settled target doesn’t always stay settled at the very next check. EMDRIA’s phase breakdown includes a later step, Reevaluation, at the start of the next session, that reruns the same rating to confirm a target held. If it drifted back up, that’s normal, and simply means there’s more to process.

Once distress is low, EMDR also tracks a second number: VOC, Validity of Cognition. EMDRIA’s glossary defines this as how true a wanted belief feels, on a 1-to-7 scale, rather than how distressing the memory feels. SUD tracks how much a memory still hurts; VOC tracks how solid a healthier belief feels standing next to it. A target isn’t considered settled until SUD is near 0 and VOC is near 7.

How do you use it during a self-guided session?

You don’t need a clinician in the room to use this. Whether you’re following self-guided bilateral stimulation manually or practicing with EmEase, a self-guided EMDR app, at your own pace, the same basic pattern works:

1. Bring the trigger to mind, loosely, and rate your distress, 0 to 10.
2. Run one round of bilateral stimulation. Eye movements, tapping, or audio, whichever you’re using.
3. Rate again. Same target, same scale, right now.
4. Repeat while the number keeps dropping, and stop for the day once it plateaus or settles low.

Two numbers, before and after, turn a vague sense of “that helped, maybe” into something you can actually check. Our guide to tracking your progress covers logging this over several weeks instead of one sitting, so you can see a real trend instead of guessing from memory.

What should a high number tell you to do?

A rising or stuck-high number is useful information, not something to push through. If your distress climbs above a 7 and doesn’t settle after a few rounds, stop. Ground yourself: feel your feet on the floor, name a few things you can see, slow your breathing. That’s a sign you’ve moved outside your window of tolerance, the zone where you can feel something without being overwhelmed by it, and pushing further from there tends to backfire rather than help.

A single hard session doesn’t mean anything is wrong. A pattern is what to watch for: the same target opening higher than it closed last time, several sessions in a row that won’t come down, or a number that won’t move no matter what you try. That pattern is worth bringing to a professional rather than continuing to work through it alone. Our guide on when to stop self-guided practice and see a professional walks through that line in more detail.

Is the SUD scale scientifically precise?

Short answer: it’s a useful personal gauge, not a lab instrument, and both things can be true. The 2008 study mentioned above followed patients through EMDR treatment and found their SUD ratings correlated with an independent clinician’s separate assessment of how much they’d improved. The number tracks something real.

At the same time, the 2025 review mentioned above is right that a single score, from a single evening, isn’t precise enough to lean on too hard. Read your own numbers as a trend across many ratings, not a verdict from one. That’s true whether a therapist is scoring them or you are.

The bottom line

You don’t need a therapist’s training to use the SUD scale honestly. Set your own 0 and your own 10, rate what’s true right now instead of what you think you should feel, and watch the number as a trend instead of judging any single evening. That’s the whole method. Everything else, EMDR sessions, self-guided practice, tracking progress over weeks, is this same small habit, repeated.