Some steroids ‘may change brain structure’, study finds

Some commonly prescribed steroids, such as inhalers, may cause changes in brain structure, a study has revealed.

Researchers at the University Medical Centre in Leiden, Netherlands, found that prolonged use of systemic glucocorticoids – widely used to treat autoimmune and inflammatory skin diseases – have previously been linked to potential side effects in the long term.

But the team of scientists said that any studies on the impacts of glucocorticoids on the brain have been small.

They examined the impact of systemic steroids and inhaled steroids on the brain by assessing differences in brain grey matter volume and the white matter microstructure in users compared to non-users.

The team examined data on 222 systemic steroid users, 557 inhaled steroid users and 24,106 matched people for comparison. All participants were drawn from the UK BioBank study.

Experts examined MRI scans of the brain on both those taking the drugs and those who were not, and found that both systemic and inhaled steroid use was associated with “reduced white matter integrity” compared with those who did not take the drugs.

The effects were greater in systemic users than in those who took inhaled steroids, and they also found changes to grey matter in the brain among users.

The study, published in the journal BMJ Open, said systemic use was associated with larger grey matter volume in the caudate structure in the brain - which controls the planning of movement and learning, while inhaled users had smaller amygdala grey matter volume - the part of the brain that controls emotional responses.

Systemic users were also more likely to self-report symptoms of depression, disinterest, restlessness and tiredness compared to the control group.

Inhaled users only reported more tiredness and lethargy compared to the controls.

“This study shows that in the large population-based cohort of the UK Biobank, the use of not only systemic glucocorticoids but also inhaled glucocorticoids is associated with changes in several brain imaging parameters,” the authors wrote.

“Most notably, the previously reported glucocorticoid effects on white matter microstructure were also detected in this population and are therefore likely to be widespread among glucocorticoid users.”

They added: “While it remains unclear whether the observed effect sizes have clinical consequences for the population of glucocorticoid users as a whole, these findings are remarkable given the common neuropsychiatric side effects of synthetic glucocorticoids, and the observed changes may play a role in those patients suffering from these side effects.”

Additional reporting by Press Association