Dads with 'postnatal' depression are more likely to fix on negatives and be more critical of themselves when talking to their new babies.
The study by Oxford University researchers is the first to look at the speech of new fathers with depression in their early interactions with their babies.
'We found there were differences in the way depressed dads talked to their babies compared to fathers without depression,' said Dr Vaheshta Sethna, first author of the study at the Department of Psychiatry at Oxford University. 'They tended to be more negative and be more focused on themselves.'
Dr Sethna, who has since moved to the Institute of Psychiatry at King’s College London, added: 'It is possible that babies will pick up on this negativity, that they will pick up on these cues even early in life. For example, the baby may have to respond differently to get attention.'
The Wellcome Trust-funded research is published in the journal Psychological Medicine.
Around 4% or 5% of fathers are thought to get depressed in the postnatal period, around half the rate for mothers. And as with postnatal depression in mothers, it has been shown that their children are at increased risk of developing emotional and behavioural problems.
One way that depression could affect the children is in changing the way fathers interact with their babies. So the Oxford research team set out to compare the speech of depressed fathers to their three-month-old children with fathers who were not depressed.
38 fathers, half of whom were depressed, were asked to play with and speak to their three-month-olds for 3 minutes. The babies were sat in their infant seats, and the face-to-face interaction videoed.
The researchers found that fathers with depression were more negative about themselves and their infants in their speech in comparison to fathers who weren’t depressed. Their words also focused more on themselves and their experiences, and less on the infants.
Examples included: 'I’m not able to make you smile'; 'Daddy’s not as good as Mummy'; 'Are you tired?'; 'Oh-oh, Daddy hasn’t lasted very long, has he?' and 'Can’t think of anything to do all of a sudden'.
The proportion of comments showing some negativity rose from an average of 11% among fathers without depression to 19% in fathers with depression. The proportion of the fathers' comments that were focused on the baby dropped from 72% to 60%, while the proportion that focused on themselves rose from 14% to 24%.
Lead researcher Dr Paul Ramchandani from Oxford’s Department of Psychiatry said: 'We want to try and work out the processes that lead to poorer outcomes in the children so we can work out where parents can be helped out. More research has been done with mums with postnatal depression and there are a range of early interventions to help them in the way they talk and play with their babies. Depression in fathers is less well recognised and fewer fathers tend to come forward for help.
He explained: 'Interventions are often based on playing parents video feedback on how they are with their babies. We can show parents how their children are communicating back, helping them recognise this and respond.'
Dr Ramchandani added: 'This was a small study and we have not yet investigated whether differences in the way fathers talk to their babies leads to poorer emotional development and behavioural problems later. That’s the next step'
'It’s important to remember that depression among parents doesn’t mean that the children are going to have problems. Most do not.'