While depression isn't an inevitable part of aging, women are twice as likely as men to develop the mood disorder, and that can have significant health repercussions later in life, doctors say.
At a conference on aging and memory in Toronto on Tuesday, clinical psychologist Nasreen Khatri said experiencing bouts of depression during one's life can double the risk of developing Alzheimer's disease and possibly other forms of dementia when women reach old age.
"The fastest-growing segment of the population right now is older women," Dr. Khatri, clinical leader of the mood and related disorders clinic at Baycrest, said. "So the older a population is, the more depressed people it has in it because it's the kind of disorder that starts young and keeps going.
"It waxes and wanes throughout life."
Dr. Khatri said women, especially those in mid-life, may be more prone to depression than their male counterparts because of the stresses and strains of juggling multiple roles in life, including working and acting as the primary family caregiver.
"There's the interaction between being a caregiver to children who aren't launched yet, because we launch our children later in life, and then care giving for parents" – both of which can increase the risk of developing depression, she said.
"What happens is that it becomes more exponential when they're doing a lot of those different activities at once."
Women may also be more prone to depression than men because of hormonal cycles and their style of coping with stress, Dr. Khatri said.
"A lot of the sense of self for women is invested in how their relationships are going ... So if something is not going well in the relationship, it can be more depressogenic for women," she said, noting that women often will deal with a problem by continually ruminating about it, while men tend to be more action-focused.
"These are generalizations. It's not to say that all men or all women interact in this way, but historically this is what has been put forth" to explain the difference in the prevalence of depression among males and females.
Dr. Khatri said mid-life and older women often experience cognitive problems as part of depression, and the No. 1 reason patients aged 60 and over come to see her is because they're worried they have dementia.
"It's not that they're not experiencing subjective distress, it's just that the overriding thing is they can't keep their schedule straight, they can't stay on top of things and they think that they might be having some kind of cognitive impairment," she said.
"When I ask them what they're forgetting, I get a list as long as my arm, so I know they're not demented," Dr. Khatri said, laughing.
Still, even after sadness and other symptoms of depression lift, some patients retain a cognitive fogginess. And with the increased risk of dementia later in life, Dr. Khatri said it's one more reason why anyone suffering depression for more than a few weeks should seek treatment.
Treatments, including cognitive behavioural and other talk therapies as well as medications, are tailored to fit the individual.
Psychiatrist David Conn, Baycrest's vice-president of education, said research has shown that chronic, untreated depression can also shorten a person's life, and keeping a positive attitude is one way to keep it at bay.
One U.S. study of middle-aged adults who were tracked over a 20-year period found that participants who had a highly positive attitude towards aging had dramatically better survival rates compared to those who had a blacker stance on getting older.
"In fact, they outlived the people with the negative attitude by over seven years (on average)," said Dr. Conn, who held a workshop on aging and mental health at the conference.
Dr. Conn believes most people don't dread getting older as long as they remain relatively healthy and able to do the activities they enjoy.
But as the years pile up, there are bound to be losses – from the death of a spouse and friends to the erosion of health and one's independence – and these can all lead to depression, he said.
"Obviously, trying to maintain an optimistic view of things is critically important," said Dr. Conn, who encourages people to take part in mood-enhancing activities such as regular exercise, eating well, getting proper sleep and using one's skills.
"And maintaining and nurturing close relationships, nurturing one's spiritual self – all of these things can be helpful."