SUD tracking between sessions: a guide for EMDR practitioners

The SUD scale is one of the most familiar tools in any EMDR practitioner's vocabulary. You use it constantly in session — at the start of a processing set, after each pass, as you track whether a target is moving toward resolution. SUD 7. Now a 4. Now a 2. Closing toward 0 or ecological 1. The number anchors the work.

What most EMDR practitioners have relatively little data on is what happens to their client's distress arc in the six days between appointments. The SUD at the end of Monday's session might be a 1. By Wednesday, has it crept back up? Has the material settled? Is the client experiencing the ongoing processing that EMDR commonly produces — or are they destabilizing?

Between-session SUD tracking isn't yet standard clinical practice. But the case for it is stronger than most practitioners have had tools to explore.

What the SUD scale is actually measuring

Before getting into between-session use, it's worth being precise about what SUD measures — and what it doesn't. The scale, developed by Joseph Wolpe in the context of systematic desensitization, measures the client's subjective sense of distress at a given moment, anchored to a specific target or experience. It's a self-report measure, which means it's sensitive to a client's awareness of their own state, their willingness to report accurately, and the specific way you've asked them to tune into the target.

In session, this is constrained by the clinical context. You're guiding attention to a specific memory or belief. The bilateral stimulation is running. The client is in a structured altered state — not quite ordinary consciousness, not fully dissociated. The SUD they report is a direct read of their activated distress on that material.

Between sessions, the picture is messier. A client reporting a SUD of 5 on Thursday morning might be reporting the ambient activation from ongoing processing, a reaction to a trigger that occurred independently, or their state on a completely different piece of material that came to the surface. Context matters a great deal.

This isn't an argument against between-session tracking — it's an argument for doing it carefully and interpreting the data appropriately.

What between-session SUD data can tell you

Even with the caveats about interpretation, between-session SUD data gives you clinical information that session-only measurement simply can't:

Processing trajectory. If a client ends a session at SUD 1 and arrives the following week at SUD 6 on the same target, that tells you something. The material isn't holding its resolution. Whether that's because the target isn't fully processed, there's a feeder memory driving it back up, or the client encountered a real-world trigger — knowing the arc changes how you open the session.

Baseline distress drift. Clients who are benefiting from EMDR tend to show a gradual downward drift in their baseline distress over weeks and months. If you're only measuring SUD within sessions on specific targets, you can miss this drift — or fail to notice when it reverses. Longitudinal tracking across multiple sessions on multiple targets surfaces the trend.

Between-session regulation. A client who starts a self-directed resourcing session at SUD 4 and ends it at SUD 1 has demonstrated something important: they can regulate their own nervous system using the tool you've given them. That's both a data point and a clinical milestone. Clients who can self-regulate between sessions are typically progressing faster than those who can't.

Red flags for destabilization. A client whose between-session SUD scores are consistently high — 6, 7, 8 across multiple check-ins — isn't maintaining gains. That's information you need before the next session, not after. With between-session data, you can reach out proactively rather than discovering it in your first five minutes together.

Practical considerations for tracking

The challenge with between-session SUD tracking is simply logistics. Calling or texting clients mid-week to ask for numbers is impractical at scale. Paper logs require clients to remember, find the log, and remember what they were feeling. Most don't complete them consistently.

What works better is collecting SUD data as part of a structured between-session activity — one where the client naturally begins and ends by rating their distress level. This turns the tracking from an added task into an integrated part of what they're already doing.

The start-of-session SUD establishes a baseline for that particular practice. The end-of-session SUD measures movement. Over multiple sessions, you get a curve: pre-session distress over time, post-session distress over time, and the delta. That data is clinically meaningful in a way that isolated self-report isn't.

How to integrate SUD data into your clinical workflow

The most useful way to use between-session SUD data isn't to pour over it obsessively — it's to glance at the trend before each session and let it inform your opening. A few questions worth running:

• Is baseline distress (pre-session SUD) trending down over time? That's the sign EMDR is working.
• Is there a gap between end-of-session SUD and start-of-next-session SUD that's consistently large? That suggests the material is reactivating between appointments.
• Are there outlier sessions — spikes in pre-session distress that don't fit the overall trend? Those are worth asking about. Something happened that week.
• Is the client completing between-session sessions at all? Frequency matters. A client who rarely engages between sessions will have different outcomes than one who uses the tool consistently.

None of this replaces clinical judgment. SUD scores are one input among many. But having the data means you're not flying blind in the time your client spends away from your office.

A note on the limits of self-report

It's worth saying directly: SUD scores, in session or between sessions, are self-report. They reflect a client's conscious access to their own distress state, which is itself a clinical variable. Clients who dissociate, who minimize, who are alexithymic, or who have a strong pull toward reporting what they think the therapist wants to hear — their SUD data requires interpretation, not just recording.

Between-session scores compound this somewhat, because clients are reporting without the structured context of a session. A client who experienced a significant flashback on Wednesday but has partially suppressed it by the time they do their Thursday session may report a lower SUD than their Wednesday self would have.

This is an argument for collecting multiple data points over time rather than relying on any single score. Trends are more reliable than individual measurements. And trends, even in imperfect self-report data, are visible — if you're collecting the data to see them.

When I started reviewing my clients' between-session SUD data before each appointment, I stopped being surprised by what they walked in with. That alone changed how efficient our sessions were.

The clinical case for between-session monitoring

EMDR has strong outcome data. The therapy works. But most of that research measures outcomes at termination or follow-up — not the week-to-week trajectory that therapists actually navigate with their clients. Between-session SUD tracking is a simple way to build a longitudinal picture of that trajectory for each client you see.

The infrastructure for doing this well — structured between-session sessions with pre/post SUD capture, aggregated in a dashboard the therapist can review — is now available. The clinical question isn't whether the data would be useful. It's whether you're collecting it.