PRESCRIPTION steroids can wreck your mental health by damaging the brain, according to a study.
Millions of Brits take the strong medicines for conditions like asthma, arthritis and allergies.
But scans reveal long-term use leads to structure changes in white and grey brain matter.
It could trigger anxiety, depression and other mental health issues, said scientists at Leiden University in the Netherlands.
Study author Professor Onno Meijer said: “These findings are remarkable given the common psychiatric side effects of glucocorticoids.”
Experts studied brain scans from 25,000 middle-aged people in the UK – including 779 who were taking steroid medication pills or inhalers.
People on the meds had “less intact” white matter, they found.
White matter is packed with vital nerves that transmit information around the skull.
Physical damage makes the nerves less able to function.
Steroid use was also linked to size changes in the caudate and amygdala brain regions, which control emotions.
Past studies have found patients are at higher risk of depression than people not taking the medicines.
The drugs, known as glucocorticoids, work by controlling the body’s immune system and stopping it over-reacting.
This reduces the risk of asthma attacks, severe allergic reactions or joint pain and swelling caused by arthritis or lupus.
Writing in the journal BMJ Open, Prof Meijer said: “These medications are prescribed for a wide range of conditions and are used by a substantial proportion of the population.
“Awareness of the potential of glucocorticoids to affect the brain and cause neuropsychiatric symptoms is important.”
Researchers added that long-term steroid use is “associated with many potentially serious metabolic, cardiovascular and musculoskeletal side effects.”
NHS advice says patients may get side effects from steroid medicines but adds: “Do not stop taking your medicine without talking to your doctor.”