Long-term steroid use can reshape the structure of the brain, causing some parts to shrink and others to grow, a major new study reports.
People taking steroids — even inhaled steroids — appear to have less intact white matter structure in their brains compared with those not taking the drugs, brain scans reveal. White matter serves as the communication link between different regions of the brain.
Scans also showed changes in brain regions associated with thinking, reasoning and emotional processing, according to findings published Aug. 30 in BMJ Open.
These changes could help explain why people on long-term steroids sometimes report mental effects from the drugs, including anxiety, depression, mania and delirium, researchers argue.
For example, studies have shown that people prescribed steroids are seven times more likely to attempt suicide, researchers said in background notes.
"Since these medications are widely used, awareness of these associations is necessary across medical specialties, and research into alternative treatment options is warranted," concluded the researchers led by Merel van der Meulen, from Leiden University Medical Center in the Netherlands.
For their study, the investigators reviewed MRI data collected as part of UK Biobank, an ongoing effort to regularly gather in-depth genetic and health information from more than half a million residents of the United Kingdom.
They identified 222 people who took steroids as an infusion or a pill, and another 557 prescribed steroid inhalers to help deal with asthma or other lung ailments.
The researchers then compared the brain scans of steroid users against scans of more than 24,000 other people who weren't prescribed the drugs.
Steroid users had less white matter in their brains, "which may in part underlie the neuropsychiatric side effects observed in patients using glucocorticoids," researchers reported in their study.
Systemic use of steroids was associated with a larger caudate, while use of inhaled steroids was associated with a smaller amygdala. Both of these gray-matter brain structures are involved in the processing of thoughts, memories and emotions.
People included in the study also participated in tests that gauge brain power and emotional makeup.
Systemic steroid users performed worse on a test designed to measure their brain's processing speed, and they reported significantly more symptoms of depression, apathy, restlessness and fatigue or lethargy. Inhaled steroid users only reported more fatigue.
It makes sense that steroids would have an effect on the brain, "because we know that steroids change things in your body," said Dr. Stephen Jones, a neuroradiologist with the Cleveland Clinic.
"If you're on long-term chronic steroids, you're going to have obesity, you're going to have fat deposition, you might have body water changes," Jones said.
Jones praised efforts like UK Biobank that are gathering mounds of medical data that can then be used to draw significant associations.
"This fairly interesting result is showing that steroid use is indeed changing some microstructure in the brain," Jones said. "It's very small. I don't know if it's clinically significant at all, but it's something that we can now measure by the power of having tens of thousands of MRIs to look at."
Further study will be needed to see if these changes are signs of irreversible brain damage, or if people's brains would return to normal if they stopped taking steroids, Jones added.
This future research could "follow these patients for the next decade, and they'll be able to actually determine whether these changes are actually associated with damage or not," Jones said.