Suicide and depression-Genetics
Two variations a gene appear more frequently in depressed patients who contemplate suicide during treatment with an anti-depressant medication (citalopram, similar to floxetiine or Prozac). The study was conducted by dr. Gonzalo Laje of the National Institute of Mental Health in Bethesda, MD, USA (October 2007 issue of American Journal of Psychiatry).
The study involved 1,915 depressed patients from across the U.S. The participants received either citalopram for up to fourteen weeks or a placebo. The study then looked at gene variations in the 120 participants who developed suicidal thoughts during the study and compared them with those who did not have such thoughts. (Generally, about 4% of those taking antidepressatns start to think about suicide).
The study identified two crucial genes that contribute to the formation of cell receptors of glutamate. Variants in these genes appear to promote suicidal thinking in patients receiving antidepressant treatment. The highest incidence of suicidal thinking occurred in the 1% of the patients who had inherited at least one variant copy of the first glutamate gene. About 1/3 of these persons exhibited frequent suicidal thinking.
About 41% of the participants had one or two variant copies of the second glutamate gene, but not the first. 20% of these people developed suicidal thinking.
58% of the participants had no variant genes and of this group, less than 5% developed suicidal thoughts while on medication. Also of note, only 25% of patients who developed suicidal thoughts recovered from depression while taking medication, while 42% of patients who did not have such thoughts recovered.