One of the largest studies ever conducted on childhood bedwetting has delivered a finding that could reshape how pediatricians think about a condition millions of families dismiss as a simple developmental phase. Children who wet the bed at night, a condition known as nocturnal enuresis, face nearly double the risk of being diagnosed with attention-deficit/hyperactivity disorder or autism spectrum disorder compared with children who do not wet the bed, according to a nationwide register-based cohort study from Denmark published in BMC Pediatrics. The research, led by Laura Bech Polcwiartek of Aalborg University Hospital together with colleagues across Danish and Belgian institutions, followed an extraordinary 124,558 children diagnosed with nocturnal enuresis and 373,674 age- and sex-matched controls without the condition, drawing on Denmark’s comprehensive national health registers to capture diagnoses made between January 1, 1996, and December 31, 2023.

The headline numbers are striking. During follow-up, 11.3 percent of children with nocturnal enuresis went on to receive a diagnosis of ADHD or autism spectrum disorder, compared with just 5.6 percent of children in the matched control group. After adjusting for age, sex, comorbidities, and concomitant medication use using Cox proportional hazards models, the researchers calculated an adjusted hazard ratio of 1.87, with a 95 percent confidence interval of 1.83 to 1.91. That means children with bedwetting had an 87 percent higher hazard of receiving one of these neurodevelopmental diagnoses than their peers. Notably, the estimates were similar when ADHD and autism spectrum disorder were analyzed individually, suggesting the association is not driven by one condition alone but reflects a broader overlap between bedwetting and neurodevelopmental differences.

Nocturnal enuresis, the involuntary passage of urine during sleep in children old enough to be expected to be dry, is one of the most common childhood conditions worldwide. It arises from a complex interplay of factors, including nocturnal polyuria, reduced bladder capacity, and an elevated arousal threshold that prevents the child from waking when the bladder signals fullness. Most children outgrow it, and standard treatments such as the antidiuretic hormone desmopressin or the enuresis alarm are effective for many. But clinicians have long observed that a subset of children respond poorly to treatment or remain in therapy for years, and the new study provides the strongest population-level evidence yet that this treatment-resistant group may include a substantial proportion of children with undiagnosed neurodevelopmental conditions.

The study’s second major finding may prove even more consequential for clinical practice. Among children with nocturnal enuresis, those who were diagnosed with ADHD or autism spectrum disorder during the course of their bedwetting treatment spent dramatically longer in therapy than children without these diagnoses. The median treatment duration was 5.2 years for children with co-occurring ADHD or autism, compared with just 0.8 years for neurotypical children, a more than sixfold difference. In other words, while most children without neurodevelopmental conditions resolved their bedwetting within months, children with ADHD or autism often remained in treatment for years, a pattern consistent with the idea that underlying neurodevelopmental differences can make the behavioral and physiological pathways to nighttime dryness harder to achieve.

The researchers also uncovered a temporal nuance with practical implications. Children who received an ADHD diagnosis early in their enuresis course had a shorter treatment duration than those diagnosed later in the course of therapy. This suggests that the timing of recognition matters: when clinicians and families identify a neurodevelopmental condition early, treatment can be adapted to the child’s needs sooner, potentially shortening the overall journey. Conversely, delayed diagnosis may mean months or years of standard enuresis therapy that fails to account for the child’s underlying neurology, prolonging frustration for families and consuming healthcare resources without addressing the full picture.

What might explain the biological link between bedwetting and neurodevelopmental conditions? The authors and the broader literature point to shared pathways rather than a single cause. ADHD and autism spectrum disorder both involve differences in brain regions that regulate arousal, attention, and executive function, and the same arousal systems govern the ability to wake in response to a full bladder. Children with ADHD may also struggle with the behavioral components of enuresis management, such as adhering to fluid schedules, remembering to take medication, or responding consistently to alarm training. In autism, sensory processing differences and difficulties with interoception, the perception of internal bodily signals, may blunt the child’s awareness of bladder sensations both while awake and asleep. Shared genetic factors may also contribute, as family studies have long hinted at overlapping heritability between elimination disorders and neurodevelopmental conditions.

The methodological strength of the study lies in its scale and design. Because it drew on complete national registers covering all Danish residents under 18 over nearly three decades, it avoided the selection biases that plague clinic-based studies, which tend to capture only children referred to specialist care. The 1:3 matching of children with enuresis to controls without the condition allowed the researchers to isolate the association between bedwetting and subsequent neurodevelopmental diagnoses, while the adjustment for comorbidities and concomitant medications helped guard against confounding. Register-based diagnosis of ADHD and autism spectrum disorder in Denmark has been validated in previous research, lending credibility to the outcome measures. As with all observational studies, however, the association does not prove that bedwetting causes neurodevelopmental conditions or vice versa; the most plausible interpretation is that both reflect shared underlying neurobiology.

The clinical implications are immediate and actionable. The authors conclude that underlying ADHD or autism spectrum disorder should be considered in children with treatment-refractory nocturnal enuresis, meaning bedwetting that does not respond to standard therapy or that requires unusually prolonged treatment. For pediatricians, this reframes a stubborn case of bedwetting not merely as a urological problem but as a potential early flag for neurodevelopmental screening. Because ADHD and autism diagnoses are often delayed, particularly in children without obvious behavioral difficulties, a condition as visible and commonly reported as bedwetting could serve as an accessible entry point for earlier identification. Earlier recognition, in turn, opens the door to tailored support for the child at home and school, and to enuresis treatment strategies adapted to the child’s attention, sensory, and behavioral profile.

For parents, the findings should prompt awareness rather than alarm. The vast majority of children who wet the bed do not have ADHD or autism, and bedwetting alone is not a diagnosis of anything. Roughly one in ten children with enuresis in the study received a neurodevelopmental diagnosis during follow-up, meaning most did not. But the doubling of relative risk is large enough that persistent or treatment-resistant bedwetting warrants a conversation with a pediatrician about the child’s broader development, including attention, communication, social interaction, and sensory sensitivities. Families caught in years of unsuccessful alarm training or repeated medication trials may find in this research an explanation for why standard approaches were not working, and a rationale for asking about a wider developmental assessment.

The study, which received no external financial support and was conducted under Denmark’s framework permitting register-based research without individual consent, adds to a growing recognition that childhood conditions long treated in isolation, from sleep problems to elimination disorders to developmental differences, are often interwoven. With more than half a million children followed across 28 years of national data, it stands as one of the most definitive demonstrations that the bladder and the brain tell a shared story. For the millions of families navigating bedwetting, and for the clinicians treating them, the message is clear: when the standard playbook fails, look deeper. The child’s nighttime struggles may be the first visible signal of a neurodevelopmental profile that, once recognized, changes the entire course of care.

Subject of Research: Association between nocturnal enuresis and ADHD or autism spectrum disorder in children and its impact on treatment duration

Article Title: ADHD and autism spectrum disorder in children with nocturnal enuresis: association and impact on treatment duration — a nationwide register-based cohort study

Article References: Polcwiartek, L. B., Jørgensen, C. S., Kragholm, K., Andersen, M. P., Torp-Pedersen, C., Borch, L., Dossche, L., & Hagstrøm, S. (2026). ADHD and autism spectrum disorder in children with nocturnal enuresis: association and impact on treatment duration — a nationwide register-based cohort study. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07635-3

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07635-3

Keywords: nocturnal enuresis, ADHD, autism spectrum disorder, children, pediatrics, neurodevelopmental disorders, register-based cohort study, epidemiology, bedwetting, treatment duration, Denmark, incontinence

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