Breastfeeding Linked to Fewer ADHD Symptoms

Researchers followed 37,643 Norwegian children born between 1999 and 2009 to examine whether early feeding patterns influence attention‑deficit/hyperactivity disorder (ADHD) symptoms later in childhood. They found that each additional month of full breastfeeding—meaning the infant received only breast milk and no formula or solid foods—was linked to lower parent‑reported scores of hyperactivity, impulsivity, and inattention at ages three, five and eight.

Genetic and Sibling Analysis

To separate the effect of early feeding from family background, the team calculated polygenic risk scores for ADHD based on thousands of DNA variants for each child, and also used the parents’ scores. After adjusting for socioeconomic factors such as maternal education, birth weight and season of birth, the association between longer exclusive breastfeeding and fewer ADHD symptoms remained statistically significant.

A sibling‑comparison analysis of 5,000 pairs where one child was breast‑fed longer than the other showed a similar pattern: the longer‑breastfed sibling had modestly lower ADHD symptom scores. The effect size was small for any single child, but it suggests that breast milk or the nursing experience may influence brain development, even though the exact biological mechanism remains unclear.

The study is observational and relies on parent questionnaires, so bias and loss to follow‑up could affect the results. Nevertheless, the findings are consistent with the World Health Organization’s recommendation of exclusive breastfeeding for the first six months, which is believed to support overall infant health and development.