Effect on children
If depression in new parents is not detected their children suffer too, since depressed parents are less sensitive to the needs of their child, particularly infants with a tendency to cry frequently.
Babies of depressed parents receive less stimulation, which becomes a contributing factor to slower development.
In some cases, depression can lead to neglect or inappropriate force being used on the child.
This behaviour is not unusual, said Dr Elia Psouni, associate professor of developmental psychology at the university.
"Depression does not just involve major suffering for the parent, it's also a risk for the child," she said.
Fathers are not routinely screened
New mothers are routinely screened for depression and an estimated 10-12 per cent are found to be affected in their first year after giving birth. But fathers are not routinely screened.
The study of 447 new dads showed that the established method of detecting depression - the Edinburgh Postnatal Depression Scale (EPDS) - works poorly on men.
The screening method does not capture symptoms common in men, such as irritation, restlessness, low stress tolerance and lack of self-control.
"As a result current statistics may not tell the whole truth about depression in new fathers," said Dr Psouni.
A third of the depressed fathers in the study had thoughts of hurting themselves but few were in contact with the healthcare system.
Among those classified as "moderately to severely depressed", 83 per cent had not shared their suffering with anyone. The corresponding figure for new mothers is estimated at between 20 and 50 per cent.
Telling people you feel depressed is a taboo for every new parent, as you are expected to be happy, say the researchers.
Previous research has indicated that men are reluctant to seek help for mental health issues, especially depression, according to the report.
"It's doubtful that they would reveal their suffering to a paediatric nurse," said Dr Psouni.
The screening of depression in fathers should take in longer than the 12 months currently applied in studies of new mothers.
"Among dads, depression is common even at the end of the first year, which may be due to the fact that they rarely get help," she added.
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.
Or if you need to talk to someone else:
• LIFELINE: 0800 543 354 (available 24/7)
• SUICIDE CRISIS HELPLINE: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• YOUTHLINE: 0800 376 633
• NEED TO TALK? Free call or text 1737 (available 24/7)
• KIDSLINE: 0800 543 754 (available 24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• DEPRESSION HELPLINE: 0800 111 757 (available 24/7)
• SAMARITANS: 0800 726 666
• OUTLINE: 0800 688 5463 (confidential service for the LGBTQI+ community, their friends and families)
• RURAL SUPPORT TRUST: 0800 787 254.