Psychological Distress & Physical Multimorbidity in England

It's well established that people in deprived areas have worse physical health, and that mental distress and physical illness tend to go together. The open question was how those two interact. Does deprivation make distress hit harder, or do they simply stack on top of each other?

This matters practically because the two answers lead to different NHS policies. If deprivation amplifies the effect, you target mental health resources at deprived areas. If the effects are just additive, you screen everyone.

Using survey data from 4,735 adults across England, we measured psychological distress and counted each person's long-term physical conditions, then adjusted for age, sex, income, education, smoking, drinking, and region so we weren't just picking up those factors instead.

Distress and physical illness were clearly linked: each one-point increase in someone's distress score came with roughly 9.7% more physical conditions, and that held up firmly across every version of the model we tried. Living in the most deprived areas independently added about 25% more conditions.

The key test was whether those two effects multiply. They don't. When we explicitly checked whether distress hits harder in deprived areas, the result was flatly insignificant. Both raise physical illness, but they do so independently, so the extra risk carried by a distressed person is much the same regardless of where they live.