From the outside, a person pacing and speaking loudly looks like one thing. Underneath, it can be at least five. Distress is emotional pain: fear about a decision, grief, humiliation, exhaustion. Communication breakdown is a message that is not getting through in either direction: the person cannot make you understand, or cannot understand you, and the volume rises because that is what people do when they are not heard. Sensory overload is a nervous system receiving more input than it can process, common for autistic people, people with brain injuries, people with certain mental health conditions and many others, and it is caused by the room. Trauma response is the body reacting to a present cue as if it were a past danger; the person may be fighting, fleeing, freezing or complying without being able to think. Behavioral risk is a credible, imminent risk of serious physical harm to the person or someone else.
The distinction matters because each source has a different remedy. Distress needs acknowledgment and time. Communication breakdown needs a different channel: writing, pictures, an interpreter, the person’s own device. Sensory overload needs a change in the environment, not in the person. Trauma response needs safety signals, distance and choice, and usually the removal of whatever is acting as the cue. Behavioral risk needs a safety response, under your program’s policy, and even then the least restrictive one that works.
Diagnosis does not tell you which one you are seeing. An autistic person can be in distress about a decision; a person with a psychiatric disability can be overloaded by a loud room; a person with no disability at all can have a trauma response to a uniform. Watch what is happening and what is in the room, then test the least dangerous explanation first.