OTTAWA, Oct 17, 2003 (Canada NewsWire via COMTEX) -- After a pioneering seven-year study, Canadian scientists have discovered a new genetic difference in people suffering from severe depression and in those who have committed suicide. The findings by collaborative researchers at the University of Ottawa and the Institute of Mental Health Research, and McGill University's Douglas Hospital, Montreal -- represent a significant step forward in identifying individuals at risk for debilitating depression or even death.
The study - "Impaired repression at a 5-hydroxytryptamine -1A receptor gene polymorphism associated with major depression and suicide", published in a recent issue of the Journal of Neuroscience, showed the same genetic difference or 'single nucleotide polymorphism (SNP)' in a gene that contributes to the serotonin system which regulates mood cycles in human beings. This SNP in the serotonin-1A gene was two-fold enriched in people with depression, and four-fold enriched in those who had completed suicide, as compared to normal control groups.
"This study represents an important advancement in understanding major depression and suicide because for the first time, we have not only shown a genetic difference in people with illness but how this difference impacts on brain chemistry and the flow of that important 'brain signaling' molecule -- serotonin," said Dr. Paul Albert, Professor and Senior Scientist of the Ottawa Health Research Institute and a lead author of the study. "In time, and with further studies, we should be able to identify who is pre-disposed to major depression and suicide so treatment could perhaps begin before there are any symptoms."
The depression study led by Dr. Pavel Hrdina, clinical scientist at the Institute of Mental Health Research, looked at 129 individuals who had major depression and 134 matched control subjects -- 41 per cent male and 59 per cent female. The suicide study led by Dr.Gustavo Turecki, Director of the McGill Group for Suicide Studies at the Douglas Hospital, examined 218 Quebec males, 102 who had died from suicide, and the remaining control subjects, matched for age, gender and ethnicity, who had died from other causes.
In comparison to the normal or control groups, almost three times as many individuals in the depression group, and four times as many in the completed suicide group, had the same genetic trigger that caused a debilitating reduction in serotonin levels.
The studies showed for the first time that the polymorphism of the serotonin-1A gene impacts by inhibiting the function of a protein called NUDR, leading to abnormal levels of serotonin-1A gene expression and decreased serotonin, and a key factor in the incidence of depression.
"Because of the vital role of these regulatory proteins, this area should be an important new target for drug development," said Dr. Hrdina, "We have certainly isolated an important association with major depression and completed suicide, but we need to strengthen the association with more studies, and by having other centers replicate our results."
The studies were funded by the Canadian Institutes of Health Research (CIHR), the Ontario Mental Health Foundation, and the Royal Ottawa Health Care Foundation. Dr. Albert was awarded the CIHR/Novartis Michael Smith Chair in Neurosciences in 1996, in recognition and support of his genetic studies of depression and suicide.
Statistics on Suicide and Depression
- Each year, an average of 3,700 Canadians commit suicide
- The World Health Organization (WHO) estimates that in the year 2000,
approximately one million people died from suicide and that 10 to 20
times more people attempted suicide worldwide.
- In the last 45 years, suicide rates have increased by 60 per cent
worldwide and is now one of the three leading causes of death among
those aged 15 - 44 years
- While suicide is the result of many complex biological, psychological
and social factors, mental disorders (particularly depression and
substance abuse) are associated with more than 90 per cent of all
- Suicide and suicidal behaviour affects one in 13 Canadians
- In Canada, suicide is the second leading cause of death among youth
aged 15 - 24
- According to the Canadian Psychiatric Association, some Aboriginal and
Inuit communities experience suicide rates three to six times higher
than the national average.
- In the update of the Report of the Task Force on Suicide in Canada,
Health Canada reveals that young men (20 - 29) and senior men (over 75)
are at greater risk of suicide than any other age group.
- The same study suggests that while suicide is ranked as among the top
five to 10 causes of death in North America and most of Europe, suicide
does not receive the same level of attention as other public health
problems and that there is a clear need for increased awareness,
research and attention to suicide and its prevention.
- The World Health Organization predicts that within 20 years, depression
will be the leading cause of disability in the world
- A Statistics Canada Study, released in September, 2003, shows that 4
per cent of Canadians reported symptoms of major depression
- An estimated 121 million people currently suffer from depression
worldwide. An estimated 5. 8 per cent of men and 9.5 per cent of women
will experience a depressive episode in any given year
- Although depression can be successfully treated, fewer than 25 per cent
of those affected have access to treatment
Research Institutes Collaborating in the Study
- The University of Ottawa Institute of Mental Health Research (IMHR) was
established in 1990 by the Royal Ottawa Health Care Group (ROHCG) and
the University of Ottawa to advance basic and clinical mental health
research in Canada and to develop effective diagnosis and treatment
strategies for mental illness. Through interdisciplinary and
multidisciplinary collaborations, the IMHR is currently conducting
leading-edge research in the areas of mood disorders, anxiety
disorders, schizophrenia, youth psychiatry and forensic psychiatry.
Investigations in the use of efficacy of complimentary and alternative
medicine are also ongoing.
- The Douglas Hospital Research Centre has been recognized as a model
centre by the Fonds de la recherche en sante du Quebec. It is the
largest centre of its kind in Quebec, and provides leadership in the
enhancement of treatment and care for those with mental illnesses
through innovative, internationally-recognized research. The Douglas
Hospital Research Centre aims to advance knowledge of brain function
relevant to mental health and mental illness.
- The Ottawa Health Research Institute (OHRI) is the research arm of the
Ottawa Hospital, and a major part of the University of Ottawa Faculties
of Medicine and Health Science. With more than 200 scientists, 225
students and 400 support staff, and $42 million in external funding,
the OHRI's mission is to excel in research, education and innovative
patient care. Its scientists are at work on an enormous array of
questions within seven research programs: cancer therapeutics; clinical
epidemiology; diseases of aging; hormones, growth and development;
molecular medicine; neuroscience, and vision.
VIEW ADDITIONAL COMPANY-SPECIFIC INFORMATION: http://www.newswire.ca/cgi-bin/inquiry.cgi?OKEY=30843
CONTACT: For further information: Kathy Hendrick, Royal Ottawa Hospital/Institute
of Mental Health Research, Ottawa, Tel: (613) 266-6755 or Joanna Filion,
(613) 722-6521 ext. 6767 or Stephanie Lassonde, Douglas Hospital, Montreal,
Tel: (514) 761-6131, extension 2747
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Last updated: 10/23/2003 - 07:51 AM