Mums who shower their infants with affection equip them to cope well with life stressors as adults, indicates research published online in the Journal of Epidemiology and Community Health.
Despite growing interest in the role of early life experiences in adult health, most studies have relied on recall; few have tracked participants from childhood to adult life, say the authors.
They base their findings on 482 people, who were part of the US Providence Rhode Island birth cohort of the National Collaborative Perinatal Project.
The quality of their interactions with their mothers at the age of 8 months was objectively rated by a psychologist during routine developmental assessment.
At the end of each session, the psychologist completed an assessment of how well the mother had coped with her child's developmental tests and how she had responded to the child's performance.
The amount of affection and attention she gave to her child was also categorised, with descriptors ranging from "negative" to "extravagant."
Mental health was subsequently assessed in adulthood at the average age of 34, using a validated symptom checklist, which captures both specific elements— such as anxiety and hostility— and general levels of distress.
At the 8 month assessment, one in 10 interactions (46) were characterised by a low level of maternal affection towards the infant. Most (85%; 409) were characterised by normal levels of affection.
The remaining 6% (27) were characterised by very high levels of maternal affection.
When the specific elements of the checklist were analysed, those whose mothers had been observed to be the most affectionate at the 8 month assessment had the lowest levels of anxiety, hostility, and general distress.
There was more than a 7 point difference in anxiety scores between those whose mothers had displayed low/normal levels of affection and those whose mothers had displayed high levels.
And there was more than a 3 point discrepancy in hostility scores and a 5 point difference in overall general distress scores.
This pattern was seen across all the various elements of the symptom checklist: the higher the mother's warmth, the lower the adult's distress.
The authors conclude that their findings back up the assertion that even very early life experiences can influence adult health.
High levels of maternal affection are likely to facilitate secure attachments and bonding, say the authors. This not only lowers distress, but may also enable a child to develop effective life, social, and coping skills, which will stand them in good stead as adults.