THE death of a close family member or similar negative life events can act as a trigger for people with a certain genetic makeup to be influenced by depression, according to a local researcher.
An international project involving scientists from UWA investigated whether certain genes affect the body’s serotonin system and influence the development of depression.
The researchers examined gene environment interactions with serotonergic genes on depressive symptoms and neuroticism in a homogenous population-based sample of females.
They tested 415 females of various ages in a rural part of Greece who possessed several genetic variants which been found to be associated with depression outcomes.
UWA School of Psychiatry and Clinical Neurosciences researcher Nikos Stefanis says the study’s hypothesis was based on previous evidence regarding the serotonergic genes potential to influence the development of depression.
“We were asking the basic question; are genes for the serotonergic system associated with the level of depression and also associated with the personality trait neuroticism?” he says.
“Also we were investigating whether they directly affect the expression of depression, the expression of neuroticism or if there is an intermediate factor that explains the potential association.”
Professor Stefanis says they clinically assessed all the candidates and examined their personality traits and whether they had experienced any negative life events in the past year.
He says previous research had indicated that there was abundant evidence of gene involvement in depression.
The team tested genetic variants within three separate genes including TPH2 which had previously found to be associated with depression.
Using single marker analysis they determined there was a significant gene environment interaction with several TPH2 variants on depressive symptoms.
However they did not find any distinct evidence of a direct impact of serotonergic genes on depressive symptoms or neuroticism.
Professor Stefanis says one of the genes tested was found to increase the candidate’s sensitivity to negative life events and the mechanism was associated with higher levels of depression.
“So in other words we concluded that the impact of these genes on depression is conditional on negative life events and there was no direct effect on depression,” he says.
“But it seems the expression of these genes somehow interacted, so to speak, and makes people more sensitive to life events and vulnerable to depression.”
Professor Stefanis says they developed a scale of the test candidate’s negative life events which ranged from quarrels with their spouse to the sudden death of a close family member.