The relationship between autism spectrum disorder (ASD) and steroids is complex, involving medical treatments and research into potential risk factors. ASD is a neurodevelopmental condition characterized by difficulties in social interaction, communication, and restricted or repetitive behaviors. Steroids, specifically glucocorticoids like prednisone and dexamethasone, are hormones that powerfully regulate inflammation and immune responses. The connection is multifaceted, encompassing the use of these drugs to manage co-occurring medical conditions and investigations into whether prenatal exposure may influence ASD risk.
Corticosteroids and the Neuroinflammation Hypothesis
Corticosteroids, synthetic versions of the body’s own cortisol, are potent anti-inflammatory agents that suppress the immune system. This mechanism is the rationale for their relevance in ASD research, particularly regarding the neuroinflammation hypothesis. This hypothesis suggests that immune dysregulation and chronic inflammation within the brain may contribute to some symptoms or comorbidities observed in individuals with ASD.
Studies have demonstrated elevated levels of pro-inflammatory cytokines (e.g., IL-1β and TNF-α) in the brains and peripheral blood of some individuals with ASD. This finding points to an activated innate immune system, involving cells like microglia and astrocytes. Because corticosteroids can cross the blood-brain barrier and dampen this inflammatory cascade, researchers have explored their potential to moderate these processes. Early, small studies suggest that corticosteroids may lead to improvements in certain associated symptoms, including irritability and stereotypical behaviors, supporting the idea of an inflammatory component in some cases of ASD.
Clinical Application for Co-occurring Conditions
Corticosteroids are generally not prescribed to treat the core symptoms of ASD, but they are an established treatment for certain severe, co-occurring medical conditions. Individuals with ASD often experience a higher prevalence of inflammatory disorders that require medical management, such as inflammatory bowel diseases (IBD), severe asthma, and acute allergic reactions.
Clinicians may also use corticosteroids to manage specific neurological comorbidities, such as infantile spasms or Landau-Kleffner syndrome, which can sometimes co-occur with or mimic regressive forms of ASD. In cases of regressive autism, where a child loses language and social skills, the use of corticosteroids like prednisolone has been investigated due to suspected autoimmune or inflammatory involvement. These treatments are typically targeted and administered for a defined, short-term period to control acute flares or severe symptoms. The decision to use these drugs balances the benefits of controlling the inflammatory condition against the known potential for adverse effects.
Specific Risks and Behavioral Side Effects
The use of corticosteroids, even for short durations, carries risks of side effects, which can be particularly challenging for individuals with ASD. Short-term adverse effects are common and frequently involve mood and behavioral changes.
Short-Term Effects
These can manifest as increased irritability, anxiety, emotional lability, and sometimes even symptoms of mania or psychosis. Behavioral changes often include:
- Sleep disturbances, such as insomnia.
- Increased energy levels or hyperactivity.
- Increased appetite, leading to rapid weight gain.
- Fluid retention and elevated blood sugar levels.
Because individuals with ASD may already struggle with emotional regulation and behavioral flexibility, these drug-induced changes can be disruptive, requiring close monitoring by the prescribing clinician.
Long-Term Risks
Long-term exposure introduces serious risks, including Cushing’s syndrome, osteoporosis, and cataracts. Prolonged use suppresses the body’s natural production of cortisol by the adrenal glands, necessitating a slow, controlled tapering of the medication to avoid a hormonal crisis. Suppressing the immune system increases the patient’s susceptibility to infections.
Research into Prenatal Steroid Exposure and Risk
Research investigates whether maternal exposure to steroids during pregnancy could influence the risk of ASD in the child. Focus has been on systemic glucocorticoids, such as betamethasone and dexamethasone, commonly administered to pregnant women at risk of preterm labor to accelerate fetal lung maturity. These glucocorticoids cross the placenta, potentially affecting the developing fetal brain.
Large-scale registry studies have indicated that children exposed to systemic glucocorticoids prenatally may have a moderately increased risk of being diagnosed with ASD, with some findings suggesting a relative risk increase of up to 50%. This association has been observed in mothers at risk of preterm delivery, as well as those taking steroids for autoimmune disorders. The underlying mechanism is thought to involve how these powerful hormones interact with the fetal brain’s development.
These findings represent an association, not a confirmed cause, and the absolute risk remains small. For many pregnant individuals, the short-term benefit of preventing severe neonatal complications from premature birth outweighs the potential long-term risk. This research highlights the complex role of steroid hormones in the early stages of neurodevelopment.