For some older people, depression has been linked to negative thoughts that spiral out of control.
A study of people who suffer late-onset depression, defined as first emerging at age 60, showed that they did poorly on tests of exectutive function—that's the brain's ability to plan and control thoughts and actions.
Decline in executive function leads to poorer memory, rigid thinking, inattention and lowered inhibitions, concludes study leader Bill von Hippel, a psychologist at the University of New South Wales in Australia.
The study, detailed in a recent issue of the journal Cognitive Therapy and Research, involved 44 people who had either early- or late-onset depression.
"We saw that executive decline was associated with rumination—a tendency for repeated negative thinking patterns—among those with late-onset depression,” von Hippel said. "Executive decline was only associated with late-onset depression to the degree that it led people to ruminate."
Von Hippel describes rumination as problem-solving gone awry.
“Looking inward and being reflective is a useful thing to do, especially when negative events happen in our life," he said. "But if we get stuck in a pattern of saying, ‘Why me?’ there’s a risk that we can spiral into a pathology."
"For some people, these normal processes spiral out of control," he said.
More research is needed to find out whether executive decline causes excessive rumination or if some other related process is at work.