Every experienced pediatrician, child psychologist, and child psychiatrist knows this child. One week they're thriving. The next, they refuse to eat, develop obsessive fears, cannot separate from their parents, begin having motor tics, or explode in rage over minor frustrations. Parents often describe it as a switch flipping, with many saying, 'It's like I lost my child overnight.' For some families, that sudden change marks the beginning of months or years of searching for answers.
Children are frequently diagnosed with anxiety, obsessive-compulsive disorder (OCD), ADHD, eating disorders, or behavioral disorders. While these diagnoses may accurately describe symptoms, they may not fully explain what's driving them, according to Dr. Roseann Capanna-Hodge, a children's mental health expert with more than 30 years of clinical experience. Drawing on analysis of over 10,000 quantitative EEG brain maps and her own family's experience navigating PANS and Lyme disease with her son, Dr. Roseann believes one question is too often overlooked: What changed biologically?
At NeuroImmune Day, a leading conference on neuroimmune health, Dr. Roseann will challenge clinicians to look beyond symptoms and consider how the nervous system, immune system, and brain interact when a child changes almost overnight. 'When a child changes this dramatically, we have to ask a different question,' she says. 'Not simply, “What diagnosis fits these symptoms?” but “What changed biologically that caused this child to change so suddenly?”'
For decades, many children experiencing sudden psychiatric or behavioral symptoms have been viewed primarily through a mental health lens. Today, a growing body of research and clinical experience treating infection-triggered neuroimmune illness is encouraging a broader conversation. Conditions such as PANS (Pediatric Acute-onset Neuropsychiatric Syndrome), PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections), Lyme disease, and autoimmune encephalitis can trigger inflammation affecting the brain, immune system, and autonomic nervous system. For some children, the result is a dramatic change that appears overnight. What looks like anxiety may be neuroinflammation; defiance may be a nervous system locked in survival mode; a psychiatric disorder may have an underlying biological driver.
Researchers estimate that PANS alone may affect as many as 1 in 200 children, yet many healthcare professionals receive little formal training in recognizing it. As a result, families often spend months or years moving from specialist to specialist. 'Parents often tell me, “This isn't my child,”' says Dr. Roseann. 'And they're right. These children haven't simply developed a behavior problem overnight. Something has changed in the biology that's driving their behavior.'
According to Dr. Roseann, one often overlooked question is the state of the child's nervous system. 'When the brain and body remain locked in chronic survival mode, healing becomes much more difficult,' she explains. The nervous system influences emotional regulation, executive functioning, sleep, digestion, immune function, and a child's ability to benefit from therapy. Rather than viewing the nervous system as just another body system, Dr. Roseann describes it as the body's master regulator. 'When the nervous system never receives the message that it's safe, the body continues behaving as though the threat is still present,' she says.
This understanding forms the foundation of Regulation First®, Dr. Roseann's clinical framework, which sees nervous system regulation as a biological prerequisite for healing. At NeuroImmune Day, she will present 'PANS/PANDAS and the Whole-Body Matrix: Why Dysregulation Isn't Just a Brain Issue,' exploring how chronic nervous system activation affects immune function, sleep, gut health, vascular health, and executive functioning. 'We can't ask a child to heal while their nervous system still believes they're under constant threat,' she says. 'Healing begins when the body finally receives the message that it's safe.'
For parents whose child suddenly changes, Dr. Roseann encourages not waiting. 'Trust what you're seeing,' she says. 'Those changes deserve thoughtful medical evaluation and a conversation with clinicians who understand the connection between the brain, the immune system, and the nervous system.' She emphasizes that learning these changes can have biological drivers often brings relief. 'It doesn't automatically provide all the answers, but it changes the questions we ask — and sometimes that's where healing begins.'
Dr. Roseann's forthcoming book, The Dysregulated Kid: The Parenting Playbook for Helping Your Child Find Calm in a Chaotic World, published by Page Two Books on September 22, 2026, offers families practical tools based on the Regulation First® framework. The book introduces strategies including the Love Pause®, CALMS Protocol®, and 10-Minute Resets to help calm the nervous system and build resilience. 'Families don't need more blame or more behavior charts,' says Dr. Roseann. 'They need practical tools that help them understand what's happening beneath the surface and what they can do about it.'
