Depression runs in families and coping strategies, which determine our capacity to deal with the vicissitudes of life, are learnt at home.
That is why the revelation yesterday about Dr David Kelly's mother is significant. In some families, people learn how to ask for help when things get difficult. In others, they learn to cope on their own.
Everything we have heard about Dr Kelly in the past few months suggests he was a man who bottled things up. Now it appears his mother did as well, to the point where she took her own life rather than seek help.
The death of a parent for a young man - Dr Kelly was a student at Leeds University at the time - would have been a trauma in itself. If it was suicide, as he believed, it will have made him question what went wrong for his mother after she suffered her stroke, and whether he could have done more for her.
But it will also have shown him a way out of life's problems. Simon Armson, chief executive of the Samaritans and a consultant psychiatrist, said research showed that the suicide of a close friend or relative could be linked with the later suicide of the bereaved person.
"Sometimes the effect is immediate, as in copycat suicides, but in other cases, if the tragedy is not properly and fully dealt with, it may lie buried for decades before bubbling back to the surface as a result of other pressures and contributing to an emotional burden that ultimately becomes too great to carry."
The inquiry heard how an unnamed friend of Dr Kelly's at Leeds University described him as coping well with the tragedy, showing no "mental reactions" at any time and being "engrossed in his study".
Work is a common refuge for the distressed. Dr Kelly was a proud man and perhaps disinclined to open his heart, even to a close friend. Those traits, which may have been learnt from his mother, could have persisted throughout his life.
Although much of the concern over suicide is focused on the young, it is more common in the middle aged and elderly. The prospect of his career ending, with the loss of status and the respect of colleagues, in a blaze of unwelcome publicity, may have made Dr Kelly take the same way out as his mother.
TODAY AT THE INQUIRY
Lord Hutton will deliver closing remarks after statements from: Jonathan Sumption QC, counsel for the Government; Andrew Caldecott QC, counsel for the BBC; Heather Rogers QC, counsel for Andrew Gilligan; James Dingemans QC, counsel for the inquiryReuse content