If so, you are probably also a worrier, moody, irritable, nervous, fed-up, tense, lonely and guilty. In a word: Neurotic.
I have a distant and mature understanding of such propensities. Not that I am a worrier, of course, but simply that, very occasionally, I find myself worrying about things which may never happen, and becoming gloomy and anxious as a result. Only every now and then. I would explain it further and give more lurid examples, but why tempt Fate? Neurosis is bad enough without Nemesis.
So, how do we explain what makes people like us neurotic? Many people (myself included) are tempted to look back at their childhoods, identifying events which were painful and which would make just about everyone worry if life was worth living. Losing one’s keys, for example.
Perhaps the cluster of anxious or “vigilant” attitudes to life have a genetic component.
Genome-wide analysis of over 106,000 individuals identifies 9 neuroticism-associated loci
The authors say:
We report a genome-wide association study of neuroticism in 91,370 participants
of the UK Biobank cohort and a combined meta-analysis which includes a further 7,197 participants from the Generation Scotland Scottish Family Health Study (GS:SFHS) and 8,687 participants from a Queensland Institute of Medical Research (QIMR) cohort. All participants were assessed using the same neuroticism instrument, the Eysenck Personality Questionnaire-Revised (EPQ-R-S) Short Form’s Neuroticism scale. We found a SNP-based heritability estimate for neuroticism of approximately 15% (SE = 0.7%). Meta-analysis identified 9 novel loci associated with neuroticism. The strongest evidence for association was at a locus on chromosome 8 (p = 1.28x10-15) spanning 4 Mb and containing at least 36 genes. Other associated loci included genes of interest on chromosome 1
(GRIK3, glutamate receptor ionotropic kainate 3), chromosome 4 (KLHL2, Kelch-like protein 2), chromosome 17 (CRHR1, corticotropin-releasing hormone receptor 1 and MAPT, microtubule associated protein Tau), and on chromosome 18 (CELF4, CUGBP elav-like family member 4). We found no evidence for genetic differences in the common allelic architecture of neuroticism by sex.
By comparing our findings with those of the Psychiatric Genetics Consortia, we identified a large genetic correlation between neuroticism and MDD (0.64) and a smaller genetic correlation with schizophrenia (0.22) but not with bipolar disorder. Polygenic scores derived from the primary UK Biobank sample captured about 1% of the variance in trait liability to neuroticism. Overall, our findings confirm a polygenic basis for neuroticism and substantial shared genetic architecture
between neuroticism and MDD (major depressive disorder). The identification of 9 new neuroticism-associated loci will drive forward future work on the neurobiology of neuroticism and related phenotypes.
As you all know, individual differences in neuroticism are highly stable across the life course and being neurotic is associated with considerable public health and economic costs, premature mortality, and a range of negative emotional states and psychiatric disorders, including major depressive disorder, anxiety disorders, substance misuse, personality disorders and schizophrenia, so it is an important aspect of personality and may also explain the some of the causes of psychiatric disorders.
Mean neuroticism scores were lower for men than for women (men mean EPQ-R-S = 3.58, SD = 3.19; women mean EPQ-R-S = 4.58, SD = 3.26; p = 0.001). Principal component analysis of the 12 EPQ-R-S items showed that all items loaded highly on a single component, and the internal consistency (Cronbach alpha) coefficient was
Women worry much more than men. Crudely speaking, 28% more. Although only 1 man in 10 is totally phlegmatic and stable, they are twice as common as totally phlegmatic and stable women. Remember this when things go bump in the night. The authors found no evidence for genetic differences in the common allelic architecture of neuroticism by sex, suggesting to me that they have more of the same rather than something different.
A very good paper with a large sample and a clear result, which identifies 9 loci of interest where only 1 had been shown in previous research.
So, we have a first step, and future work may well push up the variance in neuroticism accounted for by the genome. There is still plenty scope for much of neuroticism to be caused by unfeeling parents, boarding schools, war zones other than boarding schools, sudden noises, and the smell of steak in passageways.