The SCAMP framework.

The two subtypes

In 2020, Oh and colleagues ran a latent profile analysis on 681 children with onychophagia (the clinical term for habitual nail biting). The analysis identified two distinct profiles, with different personality traits and different patterns of when and why biting happened.

• Automatic biters

  The hand goes without conscious notice. Biting happens during other activities (reading, watching, scrolling) and the person finds out about it after the fact. The Cognitive (focus-driven) and Motoric (pattern-driven) dimensions are usually high. Awareness training matters most for this subtype, because awareness is the gap that needs to widen first.

• Focused biters

  Biting is intentional and emotion-driven. The person knows they're doing it, often does it deliberately to manage how they're feeling, and the urge runs on stress, boredom, or restlessness. The Affective (emotion-driven) dimension is usually high. Emotion regulation tools matter most for this subtype.

Most people are a mix. The subtypes are tendencies, not boxes. But the tendency matters because the techniques that move the needle differ. Awareness training does more for an automatic biter than for someone who knows exactly when they're doing it. Emotion regulation does more for a focused biter than for someone whose hand wanders during a Netflix episode.

That single insight (the right technique depends on the profile) is the most actionable finding in the BFRB literature. The program builds around it.

Five trigger dimensions

SCAMP is the program's way of mapping a person's specific trigger pattern. Each letter is a dimension that contributes to when and why the urge fires. Most people lean on two or three of them more than the rest.

• S

  Sensory

  Texture-driven. The urge starts at your fingertips when you find something rough.

  Looks like: A hangnail catches on your sleeve. You feel the rough edge with your thumb. Within a minute, your finger is in your mouth. The ridge had to be smoothed.

  What works: Sensory substitutes (smooth stones, textured rings, nail care kits). Anything that gives your fingers a satisfying texture to work on that isn't your nail.

• C

  Cognitive

  Focus-driven. You bite when your attention is fully absorbed elsewhere.

  Looks like: You're deep in a problem at work. Or watching a show. Or scrolling. You look down an hour later and your nails are shorter than they were. The whole thing happened with you out of the room.

  What works: Brief awareness checks during focus sessions. A glance at your hands every twenty minutes pulls the behavior back into view before another half hour disappears.

• A

  Affective

  Emotion-driven. Strong feelings (stress, boredom, even excitement) set the urge off.

  Looks like: You're anxious about an email that hasn't come yet. The intensity builds. Your hands need to do something. The biting steadies you, briefly.

  What works: Emotion regulation tools (breathing, grounding, progressive muscle relaxation, calming visualization). Give the nervous system another way to do the regulation that biting was doing.

• M

  Motoric

  Pattern-driven. The hand-to-mouth movement is so automated it runs without you.

  Looks like: You're not stressed. You're not focused on anything in particular. You're just sitting there. And your hand drifts to your mouth without any decision being involved.

  What works: Decoupling. The motor pattern is going to fire either way; the intervention is sending the motion somewhere else once it starts. Practiced mentally first, then in real life.

• P

  Place

  Environment-driven. Specific locations and situations cue the behavior reliably.

  Looks like: You bite on the couch in front of a show. At your desk during work. In the car on familiar drives. Bed before sleep. The location bundles other triggers together and becomes the cue.

  What works: Stimulus control: changing what your hands are doing in those specific places. Object squeeze on the couch. Hands on the wheel in the car. The place stays, but the response changes.

The 9-question assessment

On Day 8 of the program, after a week of pure noticing, the app asks 9 questions. Each question is anchored to one or more SCAMP dimensions and asks you to answer from what you actually noticed in the previous week, not from what feels like the right answer in theory.

The result is a profile. Maybe Affective and Cognitive run high (stress plus deep focus). Maybe Sensory and Motoric (texture-hunting plus the automatic reach). Maybe Place is your dominant dimension (bed and the couch are where everything happens).

From there, Phase 2 (the active-change phase) emphasizes the techniques that fit your profile. The full toolkit is available to everyone. The difference is which tools get featured first and how the program walks you through them.

What the framework isn't

SCAMP isn't a diagnosis. The categories aren't mutually exclusive, and your profile can shift over time. A focused biter under heavy work stress might present as more automatic when their attention is fully consumed. A normally automatic biter might become more focused during a hard week. The point is to give the program a starting place.

It also isn't a substitute for clinical evaluation. People with severe presentations (significant distress, functional impairment, repeated failed attempts) sometimes benefit from professional support alongside an app. SCAMP doesn't replace that judgment. It's a personalization layer for a behavioral self-help program, scoped to that.

The source

The framework rests on one paper: Oh, J., et al. (2020). Defining Subtypes of Onychophagia in Children: A Latent Profile Analysis. Psychiatry Investigation. n=681. Score on the rubric: 21 out of 25. The honest caveat is that the underlying study population was children. The automatic-vs-focused distinction generalizes to adults in clinical practice, but the precise numbers are from a pediatric sample. I treat the framework as well-supported but not bulletproof.

That caveat sits with the rest of what the research can't tell us yet on the research overview page.