Researcher probes link between flu, depression
The work of a pioneering UBC psychiatrist suggests feeling blue
might not be all in your head
by Hilary Thomson staff writer
Can a bout of flu trigger an episode of depression? UBC Psychiatry
Asst. Prof. Cai Song thinks so. She has spent the last 12 years
looking at the interactions between the brain and the immune system.
"These are two very complicated systems," she says. "It's very
difficult for scientists to link them together. Psychiatrists and
immunologists usually don't talk."
Song, a faculty member since 1999, is particularly interested
in the relationship between immune disorders and depression.
"Anti-depressants have been used for half a century but they are
effective only about 60 per cent of the time and many patients cannot
be completely cured," she says. "There must be a better way. We
need a revolution."
Her goal is to find drugs or natural nutrition sources that would
nourish the immune system without negative side effects and to develop
better treatment for depression.
Song has a medical degree in Chinese medicine that informs her
holistic approach to health and a PhD in Neuropharmacology with
a focus on Neuroimmunology. She examines both the microbiological
and behavioural links between the nervous and immune systems.
The discipline, called psychoneuroimmunology, was not well researched
until the last decade, she says. She co-authored the first text
ever to explore the area.
Her research has shown that depressed patients show abnormalities
in their immune system and, conversely, that alterations in the
immune system can trigger chemical changes in the brain that result
in depression, anxiety and impaired memory.
For example, cancer patients who receive treatments to boost their
immune system can experience mental disturbances and develop depression.
Traumatic events and illnesses that disturb the immune system may
also have a negative effect on the chemical balance needed to keep
the brain functioning normally.
In addition, antidepressants may be helpful when the immune system
is hyper-activated because of autoimmune disorders. These include
multiple sclerosis, lupus, psoriasis and rheumatoid arthritis.
Song emphasizes that not all psychiatric illnesses are related
to immune disorders, however, ignoring the links can be dangerous.
Many antidepressants have severe side effects and are toxic to the
immune system -- the patient's psychiatric health may improve but
their overall health may decline as treatment continues.
Also, when patients with painful immune diseases such as lupus
report symptoms of depression, physicians often believe the depression
is connected to the pain, she says. Song argues that the depression
is actually caused by chemical changes in the brain triggered by
the distressed immune system.
Her research in Alzheimer's patients shows immune changes that
differed from normal aging.
She suspects the disease may be related to an autoimmune disorder
caused by aging of the thymus gland which plays an important role
in the development of immune responsiveness. The finding could lead
to new therapy options for Alzheimer's patients, she says.
In July, Song received a Canadian Institutes of Health Research
grant to further her investigations of the brain and immune systems
in depression and Alzheimer's disease.