Genetic and environmental contributions to self‐reported thoughts of self‐harm and suicide

Abstract

Thoughts of self-harm and suicidal behavior are thought to be influenced by both genetics and environment. Molecular genetic studies are beginning to address the question of which genes may be involved and whether different genes may be expressed in men and women. We examined thoughts of self-harm and suicidal behavior in a large general population twin sample including male and female same- and opposite-sex twins. In this study, data on self-reported thoughts of self-harm and suicide were obtained from self-report questionnaires (Beck Depression Inventory and Youth or Adult Self Report forms) in 6265 twin pairs (11,008 individuals) aged 11–90 (62% female) from the Netherlands Twin Registry. Liability threshold models were compared including sex and age (linear and quadratic) effects. Models were compared using measures of parsimony to calculate the simplest model to the data. A model with additive genetic and unique environmental contributions fitted the data for both males and females. There were no qualitative sex differences, but the relative contributions differed between men and women. Heritability was higher in women (0.74, 95% CI 0.65 – 0.81) than men (0.45, 95% CI 0.28 – 0.61). The remaining variance was accounted for by environmental influence unique to an individual. These results suggest contributions from additive genetic factors to self-reported thoughts of self-harm and suicide and support the continued study of both molecular genetic and individual-specific environmental risk factors.

How Do Young People Understand Their Own Self-Harm? A Meta-synthesis of Adolescents’ Subjective Experience of Self-Harm

“…From laboratory studies, we know that people who selfharm display elevated physiological arousal in response to stressors, discontinue or escape stressful tasks sooner, and report greater efforts to suppress aversive thoughts and feelings during their day (Nock 2009). Research on physiological and neurobiological factors, such as pain endurance Kirtley et al 2016) and impulse-control , and on genetic influence (Althoff et al 2012;, is of importance to gain further knowledge of the phenomenon of self-harm at a group level.…”

Disorders and borders: Psychiatric genetics and nosology

“…Of note, however, the genetic boundaries of these factors were themselves not clean as the factors were moderately intercorrelated and some disorders loaded on more than one factor. Not surprisingly, other studies have shown that symptoms that cut across diagnostic boundaries—psychosis, suicidality, anxiety—are themselves heritable [Cardno et al, ; Eley et al, ; McGuffin et al, ; Althoff et al, ; Trzaskowski et al, ].…”

Effects of CLOCK gene variants and early stress on hopelessness and suicide in bipolar depression

“…Current models of lifetime suicide risk suggest gene-environment interactions, and a recent large twin study supported a liability-threshold model with contributions from additive genetic factors and specific individual environmental influences (Althoff et al, 2012). Suicide and attempted suicide are heritable independent of the associated diagnosis (Currier & Mann, 2008), and adding up to genetic risks, early stress can increase the risk of suicide by influencing the epigenetic regulation of genes involved in stressresponse systems (Turecki et al, 2012).…”