The effect was seen within hours.15:35, 29 Jul 2026Scientists have used a drug to reverse 'autism-like brain changes' within hours. UCLA Health (a leading American hospital affiliated with the University of California, Los Angeles) says its new study "suggests that some autism-related brain changes may still be treatable in adulthood". However, it's important to note that the research was conducted on mice and that the effects of the drug are temporary.‌The study exposed mice to to inflammation during pregnancy and found that their offspring developed lasting autism-like brain and behaviour changes, "suggesting that early inflammation can disrupt brain development in ways that persist into adulthood".‌But a single dose of the drug rapamycin "rapidly improved several of those changes, including brain overactivity, seizure risk, sensory sensitivity, repetitive behaviours and abnormal brain functional network organization".‌UCLA Health said: "The findings suggest that some autism-related brain changes may still be treatable in adulthood, pointing to possible therapeutic approaches that target the underlying pathway rather than only symptoms. The effects of rapamycin are temporary, and repeated dosing loses efficacy, making rapamycin, itself, an unlikely candidate as a broadly-used treatment."Scientists have previously said that even mild inflammation during mid-pregnancy has been shown to "result in offspring autism-like symptoms, abnormal brain growth, seizures and heightened sensitivity to everyday sensory input that persists into adulthood".In the study published in the journal Nature Communications, UCLA researchers found that a single dose of the drug rapamycin given to the mice significantly improved brain signalling and behaviour symptoms in the offspring within about two hours, which they said was "a time too short to correct underlying physical brain changes created by the maternal inflammation".‌However the study authors stressed that they "do not identify rapamycin as a viable treatment for these symptoms in humans given its temporary effects and potential for toxicity from repeated doses". Instead, researchers said the drug’s effects "revealed new therapeutic targets for the development of future treatments".Dr Harley Kornblum, the study's senior author, said: "It suggests the adult brain may be more adaptable than we assumed, even when the underlying structural changes from early development are still there. This points us toward the brain's functional circuitry, not just its physical structure, as a target for future treatment approaches."Dr Janel Le Belle, an associate professor in the UCLA Department of Neurosurgery, added: "These results reframe how autism-associated symptoms might be treated. If the adult brain remains capable of functional normalisation, then some features of autism may be successfully addressed without needing to correct underlying structural differences."‌What is rapamycin?Rapamycin is licensed and used in the UK. It is primarily used in specific cases like preventing organ rejection in transplant patients and to treat specific lung diseases. Related drugs are used for some targeted forms of cancer treatment. It is also being researched for its efficacy in helping longevity and chronic illnesses like ME.What did the study do?Researchers exposed pregnant mice to mild inflammation. Their offspring went on to develop "chronic brain and body-wide inflammation, mild brain overgrowth, overactive cell-signalling in the mTOR pathway, disorganised brain functional network connectivity and behaviours associated with autism".When researchers gave the adult offspring a single dose of rapamycin, they found rapid improvement across nearly every measure: "neurons that had been firing abnormally calmed down, susceptibility to seizures dropped, brain regions that had been miscommunicating reorganised into more typical patterns and repetitive behaviours and sensory over-responsivity eased".Article continues belowThese changes occurred within roughly two hours. Researchers said that while previous studies have shown that offspring of mothers who experience inflammation while pregnant have a higher likelihood of developing "autism-associated traits" that continue into adulthood and that rapamycin has been previously shown in mouse studies to improve symptoms by suppressing an overactive pathway, it was less clear whether these brain changes could still be modifiable in adulthood.What causes autism?The National Autistic Society says evidence suggests autism may be genetic. It says: "Scientists have been attempting to identify which genes might be implicated in autism for some years. Autism is likely to have multiple genes responsible rather than a single gene. However, it is not caused by emotional deprivation or the way a person has been brought up. There is no link between autism and vaccines."