Fathers as well as mothers can experience post-natal depression - and it is linked to emotional problems for their teenage daughters, new research has found.
Almost one in 20 new fathers suffered depression in the weeks after their child was born, according to a study published in the journal JAMA Psychiatry and co-authored by Professor Paul Ramchandani of the Faculty of Education, University of Cambridge.
The research, based on a sample of more than 3,000 families in Bristol, UK, also identified a link between post-natal depression in men and depression in their daughters as they reached adulthood.
At 18, girls whose fathers had experienced depression after their birth were themselves at greater risk of the condition, researchers found. The "small but significant" increased risk applied only to daughters; sons were not affected.
One reason for this "handing on" effect could be that post-natal depression in fathers is sometimes linked with an increased level of maternal depression, researchers concluded. This might mean that family life is more disrupted for everyone with higher levels of stress for all. It may also be that the having one or both parents with depression affects the way in which parents interact with their children.
It is unclear why girls may be more affected at this age. There may be links to specific aspects of father-daughter relationships as girls go through adolescence, the research team suggests.
The findings are important because they have implications for perinatal services, which have traditionally considered post-natal depression to be a potential problem for mothers only, the study's authors say. They highlight the importance of recognising and treating depression in fathers during the postnatal period, and call on health professionals to consider both parents when one reports depression.
Professor Ramchandani said: "Research from this study of families in Bristol has already shown that fathers can experience depression in the postnatal period as well as mothers. What is new in this paper is that we were able to follow up the young people from birth through to the age of 18, when they were interviewed about their own experience of depression. Those young people whose fathers had been depressed back when they were born had an increased risk of depression at age 18 years.
"We were also able to look at some of the ways in which depression in fathers might have affected children. It appears that depression in fathers is linked with an increased level of stress in the whole family, and that this might be one way in which offspring may be affected.
"Whilst many children will not be affected by parental depression in this way, the findings of this study highlight the importance of providing appropriate help to fathers, as well as mothers, who may experience depression."
Paternal depression campaigner Mark Williams, who set up the lobby group Fathers Reaching Out and campaigns for mental health screening for new fathers as well as mothers, said: "Fathers' Postnatal Depression impacts on the whole family when unsupported, often resulting in fathers using negative coping skills, avoiding situations and often feeling anger.
"In my experience of working with families, it's sometimes only the father who is suffering in silence but sadly very few are asked about their mental health after becoming a parent."
Earlier research by the same academic team found post-natal depression in fathers was linked to behavioural and emotional problems in their children at three and a half and seven. The effect seems to happen because paternal depression may negatively affect the way a family functions - causing conflict between partners and prompting maternal depression.
The new paper, Association of Maternal and Paternal Depression in the Postnatal Period with Offspring Depression at Age 18 Years, was based on the experiences of 3,176 father and child pairs drawn from the Avon Longitudinal Study of Parents and Children - an ongoing cohort study launched in 1991.
Co-authors of the paper with Professor Ramchandani are Leticia Gutierrez-Galve of University College London; Alan Stein and Lucy Hanington from the University of Oxford; Jon Heron of University of Bristol; Glyn Lewis of UCL; and Christine O'Farrelly of the Faculty of Education, University of Cambridge.