Neuropsychological Outcomes and Behavioural Profiles in Children with Congenital Hypothyroidism: Impact of Timing of Thyroxine Initiation – A Cross-Sectional Study from Southern India

Background/Aims: Congenital hypothyroidism (CH) is among the most common preventable causes of intellectual disability worldwide. In India, the absence of universal neonatal screening leads to delayed diagnosis and consequent neurocognitive morbidity. This study aimed to assess intelligence quotient (IQ) and behavioral profiles in children with CH in relation to the timing of levothyroxine (LT4) initiation and serum T4 levels at diagnosis. Methods: A cross-sectional study of 30 children with CH aged ≥3 years attending the pediatric endocrinology outpatient clinic at Osmania General Hospital, Hyderabad was conducted between January 2017 and December 2018. IQ was assessed using the Binet Kamat Scale of Intelligence. Behavioral profiling was performed using the Achenbach Child Behavior Checklist (CBCL). Patients were stratified by age of LT4 initiation (<1 month, 1–6 months, >6 months). Analysis included ANOVA, box plot analysis, and one-sample t-tests using SPSS version 20. Statistical significance was set at p < 0.05. Results: Of 30 patients (17 girls, 13 boys), 46.6% were initiated on LT4 after 6 months of age. Mean IQ was 79, 59.5, and 61.12 in those treated within 1 month, 1–6 months, and after 6 months, respectively. Males had significantly lower serum T4 at diagnosis (0.45 ± 0.25 vs. 2.25 ± 1.48 μg/dL; p = 0.0002) and lower IQ (46.08 ± 22.59 vs. 76.6 ± 26.89; p = 0.003). Behavioral scores were within normal limits; however, WAST (Withdrawn/Anxiety/Social/Thought) composite Score showed a trend toward elevation. Height SDS did not differ significantly between treatment initiation groups (p = 0.172). Conclusion: Children with CH in this Indian cohort demonstrated substantially lower IQ compared to internationally reported values, attributable to delayed diagnosis and suboptimal therapy adherence. Males exhibited more severe biochemical disease at diagnosis and greater neurocognitive impairment. Routine behavioral assessment and cognitive behavioral therapy should be incorporated into standard CH follow-up in resource-limited settings.