Psychological distress can increase the risk of developing arthritis, heart problems and lung disease, a study found.
Even at low or moderate levels, it was a major risk factor in developing conditions such as chronic obstructive pulmonary disease.
Southampton General Hospital researchers assessed 16,485 British adults over a three-year period to make the conclusion.
Compared to people with no symptoms of distress, the chances of developing arthritis were 57 per cent higher in those with low levels.
The odds were 72 per cent higher in those with moderate levels and 110 per cent higher in those with high levels, the study found.
Professor Catharine Gale led the trial, which was published in the Journal of Psychosomatic Research.
She said: "There is a significant gap in knowledge regarding the link between lower and moderate levels of distress and the development of chronic conditions.
"Our findings show even low levels of distress, below the level usually considered clinically significant, appear to increase the risk of developing a chronic disease.
"So intervention to reduce symptoms of anxiety and depression may help to prevent the onset of these illnesses for some people."
Professor Gale added: "The relationship between significant distress and the onset of arthritis, COPD, cardiovascular disease and diabetes is well established."
Psychological distress is a term that describes a wide range of mental health symptoms, from mild anxiety and depression to severe psychiatric disease.
UK Household Longitudinal Study data was used to examine whether psychological distress was linked with the later development of several chronic diseases.
Researchers also wanted to analyse
whether any link was explained by health habits - such as diet, exercise and smoking - or socioeconomic status.
Professor Gale and colleagues found a huge increase in the risk of developing heart disease, depending on levels of distress.
People with low levels faced a 46 per higher risk, while those with moderate levels were 77 per cent more likely to develop it.
For those with high levels, the risk increased by 189 per cent.
Similar findings were seen for COPD - an umbrella term for progressive lung diseases.
Professor Gale added: "These findings have considerable clinical and public health implications.
Screening for distress may help to identify those at risk of developing arthritis, COPD and cardiovascular disease.
"While interventions to improve distress may help to prevent and limit progression of disease, even for people with low levels of distress."
Professor Cyrus Cooper, a consultant rheumatologist and director of the Medical Research Council's Lifecourse Epidemiology Unit, described the data as "fascinating".
He said it has the potential to have a major impact, "which could not only save and change lives but also significantly reduce costs across the health service".