This study also shows that patients with bipolar disorder who were treated with lithium were found to have longer telomeres, which is a sign of slower biological aging, when compared to patients who were not treated with lithium.
‘Genetic or environmental factors linked with family risk for bipolar disorder are associated with faster biological aging.’
Lithium is the main medication used for treating this illness and the findings of the study suggest that this drug may mask the aging effects linked with bipolar disorder and can even help to reverse the effect.
The rates of aging-related diseases such as cardiovascular disease, type-2 diabetes and obesity were found to be higher among bipolar disorder patients. The reason behind this is due to faster aging at the biological level.
Further research is required of bipolar disorder patients' relatives to better understand if they were also at an increased risk for aging-related diseases. Studying unaffected first-degree relatives, who have not been treated with medications may represent a truer reflection of the relationship between aging and bipolar disorder.
Telomere length and Bipolar Disorder
The research team measured biological aging by studying a feature of chromosomes called telomeres in 63 patients with bipolar disorder, 74 patients with first-degree relatives and 80 unrelated healthy people.
Telomeres at the end of chromosomes act like 'caps'. As we age, these telomeres protect the strands of DNA, which are stored inside each of the cell. Each time a cell divides to make new cells, telomeres are shorten until they are so short that they are totally degraded that the cells cannot replicate any longer. The length of telomere acts as a marker of biological age, with shortened telomeres representing older cells.
Based on various environmental and genetic factors, the rate at which telomeres shorten across our lifespan varies, which shows that two unrelated people of the same chronological age may not necessarily be of the same age biologically.
Healthy relatives of bipolar patients were found to have shorter telomeres, when compared to those healthy controls, who did not have a family history of bipolar disorder, according to the research team from King's College London and the Icahn School of Medicine at Mount Sinai. This shows that genetic factors or environmental factors linked with family risk for bipolar disorder were also found to be associated with faster biological aging.
Scientists have also conducted Magnetic Resonance Imaging (MRI) scans to explore the relationship between telomere length and brain structure, especially in the hippocampus. Hippocampus is an area of the brain, which is involved in regulating the mood. They also found that higher rates of biological aging were linked with having a smaller hippocampus.
The authors of this study suggest that the length of telomere reduction can be linked to reduced ability of new brain cells to grow in the hippocampus. This can actually reduce the size of the hippocampus and thereby, increase the risk for mood disorders like bipolar disorder.
Findings of the Study
Scientists reported that this study provides the first evidence that familial risk for bipolar disorder was found to be linked with shorter telomeres. This explains why bipolar disorder patients are also at a higher risk for aging-related diseases.
"Our study shows that telomere length is a promising biomarker of biological aging and susceptibility to disease in the context of bipolar disorder. Moreover, it suggests that proteins which protect against telomere shortening may provide novel treatment targets for people with bipolar disorder and those predisposed to it," Dr Sophia Frangou, co-senior author of the study, from the Icahn School of Medicine at Mount Sinai.
Up until now, it has been unclear whether bipolar disorder patients are at risk of accelerated aging. However, this study shows that these patients are at a higher risk of faster aging and the drugs which are commonly used to treat may actually mask or reverse this effect, reveal Dr Gerome Breen, co-senior author, also at IoPPN.
"We still need to dissect the environmental and genetic contributions to shortened telomeres in those at high risk for bipolar disorder. For instance, do those at risk for bipolar disorder carry genes predisposing them to faster biological aging, or are they more likely to partake in environmental factors which promote aging (e.g. smoking, poor diet)? Identifying modifiable risk factors to prevent advanced aging would be a really important next step," said Dr Timothy Powell, first author of the study, from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London.
- Timothy R Powell, Danai Dima, Sophia Frangou, Gerome Breen. Telomere Length and Bipolar Disorder. Neuropsychopharmacology(2017).DOI: 10.1038/npp.2017.125