Aggression and psychopathology in persons with severe or profound mental retardation.

The team looked at adults with severe or profound intellectual disability. They wanted to know which mental-health problems travel with aggressive acts.

They built a new rating scale and gave it to caregivers. No treatment was tested; they just mapped what goes with what.

Aggression linked most tightly to two inner states: dependent personality style and signs of psychosis. The form of the behavior mattered less than the mental-health picture behind it.

Reiss et al. (1993) saw the same dance five years earlier: people with ID who were aggressive were about four times more likely to also be depressed. M et al. simply widened the lens to include other psychiatric partners.

Myrbakk et al. (2008) later repeated the link in a bigger, mixed-severity sample. They found depression can show up as screaming in severe ID and as self-injury in mild ID. The core message—look past the topography—holds across studies.

Palka Bayard de Volo et al. (2021) pooled decades of data and warned that pain, autism, and poor sleep can mimic depression. So the aggression you see might be depression, psychosis, or plain discomfort. Screen each pathway before you treat.

When a client with severe ID hits or bites, your first question should not be 'How do I stop this?' but 'What psychiatric or medical partner is driving this?' Run a brief screen for mood, psychosis, and pain every time aggression spikes. Add a dependent-personality item: does the client panic when favorite staff leave? Match your plan to the driver—not the swipe.