Anxiety tends to alter ill effects of depression

WASHINGTON - Anxiety seems to alter some of the ill effects of depression, for better or for worse, says a new study of brain activity in depressed people.

The study looked at depression and two types of anxiety: anxious arousal, the fearful vigilance that sometimes turns into panic, and anxious apprehension, better known as worry.

“Although we think of depression and anxiety as separate things, they often co-occur,” said Gregory A Miller, a University of Illinois psychology professor who led the research with his counterpart Wendy Heller at the Urbana-Champaign campus.

“In a national study of the prevalence of psychiatric disorders, three-quarters of those diagnosed with major depression had at least one other diagnosis. In many cases, those with depression also had anxiety and vice versa,” said Miller.

Researchers used functional Magnetic Resonance Imaging (fMRI) to look at brain activity in subjects who were depressed and not anxious, anxious but not depressed, or who exhibited varying degrees of depression and one or both types of anxiety.

Previous studies have generally focused on people who were depressed or anxious, Miller said. Or they looked at both depression and anxiety, but lumped all types of anxiety together.

Miller and Heller have long argued that the anxiety of chronic worriers is distinct from the panic or fearful vigilance that characterises anxious arousal.

In the new study, brain scans were done while participants performed a task that involved naming the colours of words that had negative, positive, or neutral meanings. This allowed the researchers to observe which brain regions were activated in response to emotional words.

The researchers found that the fMRI signature of the brain of a worried and depressed person doing the emotional word task was very different from that of a vigilant or panicky depressed person.

“The combination of depression and anxiety, and which type of anxiety, give you different brain results,” an Illinois university release quoted Miller as saying.

These results suggest that fearful vigilance sometimes heightens the brain activity associated with depression, whereas worry may actually counter it, thus reducing some of the negative effects of depression and fear, Miller said.

These findings were published in Cognitive, Affective and Behavioural Neuroscience.