SAVANNAH, GA. – Functional MRIs reveal neuroanatomical differences between normal worry and pathological worry in the elderly, and those differences might help explain why late-life anxiety often proves difficult to treat.
The amygdala and the subgenual anterior cingulate cortex (sACC) seem to be involved in the functional neuroanatomy of late-life anxiety disorders, Dr. Carmen Andreescu of the University of Pittsburgh reported at the meeting.
The findings, based on fMRIs of 10 nonanxious elderly people and 8 elderly people with anxiety, suggest a biological substrate for the persistent and uncontrollable characteristics of pathological worry, she said. The subjects were asked to worry while they were in the scanner, then they were asked to suppress the worry and think of “something nice” for a minute.
In the nonanxious subjects, worry induction increased activation of the amygdala and decreased activation of the sACC. During worry suppression, the scans revealed decreased activation of the amygdala and increased activation of the sACC.
Not so for the elderly subjects with generalized anxiety disorder (GAD). The fMRI revealed increased activation of the amygdala and the subgenual ACC during worry suppression, suggesting a delayed yet sustained amygdala involvement and the unsuccessful attempts of the subgenual ACC to modulate the worry process, she explained.
That the amygdala stays active during worry suppression is “the most yummy part,” Dr. Andreescu reported, explaining it this way: Tell a friend without anxiety to stop worrying, and they will. Tell someone with pathological anxiety to stop worrying, and the result might be increased amygdala activity.
“There is a paucity of data regarding late-life anxiety, but based on my preliminary data, it seems that these regions are involved in late-life anxiety, just as they are in mid-life anxiety,” she said in an interview. Significantly, when someone tries to modulate his or her worry, “the interplay between these two regions is different in healthy people and in pathologically anxious people.”
Dr. Andreescu reported no conflicts relevant to the study.