Which change in brain biochemical function is most associated with suicidal behaviour?

• A. Serotonin deficiency
• B. Dopamine excess
• C. Norepinephrine surplus
• D. GABA deficiency

Answer: (A)

Serotonin signaling in mood and impulse control is the key idea here. When serotonergic activity is reduced, regulation of mood, aggression, and impulsivity can falter, making someone more vulnerable to depressive symptoms and impulsive actions, including suicide attempts. This link is supported by findings such as lower levels of serotonin metabolites in the brain or CSF of individuals who have attempted suicide, and by clinical observations that treatments boosting serotonin signaling (like SSRIs) can reduce suicidal thoughts in many patients. Of the options, serotonin deficiency has the strongest and most consistent association with suicidal behavior, compared with the others, which are less directly tied to suicidality.