Breastfeeding duration linked to fewer ADHD symptoms in children
A Norwegian cohort study found lower ADHD symptom scores through age 8 among children breastfed exclusively for longer in infancy.
By Priya Raghavan · Science Reporter
3 min read
Children who were exclusively breastfed for longer in their first six months had fewer ADHD symptoms between ages 3 and 8, according to a University of Bergen study. The finding adds evidence that early feeding may be among several environmental factors tied to neurodevelopment, though the researchers said the study cannot prove cause and effect.
The study, published in Biological Psychiatry, analyzed data from 37,600 families in the Norwegian Mother, Father and Child Cohort Study, known as MoBa. The research team was led by Berit Skretting Solberg, a psychiatrist and researcher at the University of Bergen’s Department of Biomedicine and a senior consultant at Betanien Hospital.
What the researchers measured
According to the University of Bergen, mothers completed questionnaires six months after giving birth that recorded how long their infants were exclusively breastfed, partially breastfed, and when they began receiving other liquids or solid foods. The researchers used those answers to estimate each child’s months of exclusive breastfeeding.
The team then examined ADHD symptom levels reported later in childhood, at ages 3, 5 and 8. Solberg and colleagues found that longer exclusive breastfeeding, up to six months, was associated with lower ADHD symptom levels at all three ages.
The University of Bergen said the association appeared in both boys and girls. The relationship was strongest at ages 3 and 5 and weaker by age 8, according to the study summary.
The researchers also reported that breastfeeding in general was linked with fewer ADHD symptoms, but the pattern was stronger when breastfeeding lasted longer and was more exclusive. The strongest association was seen for exclusive breastfeeding through the first six months, according to Solberg’s team.
Genetics and family factors
The researchers treated ADHD risk as a mix of genetic and environmental influences. Solberg said psychiatric symptoms and disorders are known to be shaped by both inherited and outside factors.
The University of Bergen noted that ADHD has a substantial genetic component. It cited prior research showing that mothers with ADHD symptoms tend to breastfeed for shorter periods and are more likely to have children with ADHD symptoms, while children who develop ADHD symptoms may also be harder to breastfeed.
Those patterns can make breastfeeding look more protective than it is if researchers do not account for family background, according to Solberg. To address that issue, the team adjusted for known genetic risk for ADHD and sociodemographic factors.
The study also used sibling comparisons, looking at children within the same family who had different breastfeeding histories. After those checks, Solberg’s group still found what it described as a clear but moderate protective association between longer exclusive breastfeeding and later ADHD symptoms.
Limits of the evidence
Solberg cautioned that MoBa does not perfectly represent Norway’s population. Participants in the cohort are more likely than the broader population to have higher education levels, to breastfeed, and to breastfeed for longer periods, according to the University of Bergen.
Because of that, Solberg said the association could differ in groups where breastfeeding is less common. She also said observational studies cannot settle whether breastfeeding itself causes the lower symptom levels, and called for more research to clarify the relationship.
The University of Bergen said breast milk contains components relevant to infant growth and brain development, including long-chain fatty acids, amino acids, antibodies and beneficial bacteria. Solberg said the findings point to breastfeeding duration as one possible factor, alongside heredity, in the development of ADHD symptoms in young children.
The paper is titled “Breastfeeding and Development of Attention-Deficit/Hyperactivity Disorder Symptoms Across Childhood.” Its DOI is 10.1016/j.biopsych.2026.06.009.
This story draws on original reporting from Medical Xpress.