Study links suicidal thoughts to brain inflammation
A growing body of research issuggesting that brain inflammation could be responsible for somemajor depressive episodes. A new study from a team atthe University of Manchester has now made an even more specificcontention – linking brain inflammation to suicidal thoughts.
A major study published in 2015 found astrong correlation between a person undergoing a major depressive episodeand enhanced neuroinflammation, as measured by increased microglialactivity in parts of the brain. Microglia are a specific type ofimmune cell active in the brain and spinal cord that serve as the main form of active immune defense in the central nervous system.
Following on from that earlier study,Dr Peter Talbot from the University of Manchester set out to explorewhether this increased microglial activity could be more specificallylinked to suicidal thoughts.
Fourteen patients with moderate tosevere depression and reported suicidal thoughts took part in the study alongside thirteen healthycontrol subjects. Using a PET scan identifying a marker that signalsactivated microglial activity, the results indicated a positivecorrelation between those patients with suicidal thoughts andincreased neuroinflammation.
The biggest increases in microglialactivity were identified in the anterior cingulate cortex, a part ofthe brain known for mood regulation and one that some suggest couldbe a strong target as a biological origin of depression. Notably, there was no elevated microglial activity in those brain areas in the healthy control group.
Earlier brain studies of post-mortemsuicidal patients have shown similar forms of inflammation in these regions, but thisexamination of living patients strengthens the connection, particularly in those suffering from acute depressive episodes.
"Our findings are the first results in living depressed patientsto suggest that this microglial activation is most prominent in thosewith suicidal thinking," says Dr. Talbot.
Dr John Krystal, editor of the journalpublishing the research, Biological Psychiatry, noted this new studyto be an important observation linking suicidal ideation andneuroinflammation.
"This observation is particularly important in light of recentevidence supporting a personalized medicine approach to depression,i.e., that anti-inflammatory drugs may have antidepressant effectsthat are limited to patients with demonstrable inflammation," saysDr Krystal.
The study was published in the journalBiological Psychiatry.