Infographic: The Neurobiology of Suicidal Behavior

Scientists have identified several key neurobiological pathways with ties to suicidal behaviors. Research in the field addresses only a fraction of the complexity of this serious public health problem, and the literature on the topic is complicated by variation in study design, but the clues point to several interacting moderators of suicide risk. Three of the systems best-studied in relation to suicide are depicted below.

NOTE: The findings shown in this graphic come from studies with very different approaches to investigating suicide. Some studies control for psychiatric disorders, others don’t; different studies focus on different brain areas; and many of the findings are preliminary.

STRESS RESPONSES

Many studies have linked suicidal behaviors to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and other mediators of the body’s responses to stress.

	CRH Corticotropin-releasing hormone (CRH) has been found in higher concentrations in the brains of people who die by suicide.
	Adrenal glands People who die by suicide, and particularly those who die by violent means, may have enlarged adrenal glands.
	Cortisol Basal cortisol levels have been found to be both higher and lower than normal in people who have attempted suicide. The reactivity of cortisol to stress may also be dysfunctional in people with suicidal behaviors.
	NR3C1 NR3C1, also known as the glucocorticoid receptor, may be in lower abundance in people who die by suicide, particularly those with a history of childhood abuse.

NEURAL TRANSMISSION

Neural communication via serotonin and other neurotransmitters such as glutamate often shows signs of dysregulation in people who die by suicide.

Serotonin

Disruption of serotonin signaling has repeatedly been found in the brains of people who die by suicide.

SERT

Levels of the serotonin transporter SERT, which shuttles serotonin back into the presynaptic neuron, may be lower in people who die by suicide.

Serotonin receptors

Levels of the serotonin receptors 5-HT_1A and 5-HT_2A may be higher in people who attempt or die by suicide.

INFLAMMATION

People who die by suicide show signs of increased inflammation in the brain while epidemiological data reveal that some inflammation-related health conditions are associated with higher suicide risk.