Short Telomeres Associated with Family Risk of Bipolar Disorder
Telomeres are bits of genetic material at the end of each strand of DNA that protect chromosomes as they replicate. Short telomeres have been linked to aging and a variety of medical and psychiatric diseases. Stress and depressive episodes can shorten telomeres, while treatment with lithium can lengthen them.
Telomere length is a heritable trait, and a 2017 study by researcher Timothy R. Powell and colleagues suggests that shorter telomeres are a familial risk factor for bipolar disorder.
The study, published in the journal Neuropsychopharmacology, compared the telomere lengths of 63 people with bipolar disorder, 74 of their immediate relatives (49 of whom had no lifetime psychiatric illness, while the other 25 had a different mood disorder), and 80 unrelated people with no psychiatric illness. The well relatives of the people with bipolar disorder had shorter telomeres than the unrelated healthy volunteers.
Relatives (both well and not) and people with bipolar disorder who were not being treated with lithium both had shorter telomeres than people with bipolar disorder who were being treated with lithium.
Another finding was that longer telomeres were linked to greater volume of the left and right hippocampus, and improved verbal memory on a test of delayed recall. This study provides more evidence that taking lithium increases the volume of the hippocampus and has neuroprotective benefits for people with bipolar disorder.
