Neurobiology of Impulsivity and Aggression as Substrates of Suicidal Behavior: A Narrative Focus on the Involvement of Serum Lipids

Abstract

Previous incidental findings of an increase of suicidal risk among subjects with low cholesterol levels have drawn attention to the role of lipids in suicidal behavior. To date, multiple lines of evidence acquired from clinical studies have confirmed an association between low cholesterol levels and suicidal behavior, but the involvement of dimensional traits including impulsivity and aggression in this association remains elusive. In this narrative review, we aimed to address and synthesize the literature regarding the involvement of lipids in the neurobiology of suicidal behavior and its underlying psychological substrates, impulsivity and aggression. An electronic database search was performed using different combinations of relevant keywords. Both preclinical and clinical studies matching the scope of this article were reviewed and filtered through an inspection of the abstracts to recruit the most suitable articles that contributed essential and substantial findings to the literature. Although subject characteristics and study designs vary across studies, current research has demonstrated that impulsivity and aggression might have shared neurobiologic substrates involved in altered serotonergic neurotransmission. Despite the association between low serum lipid levels and suicidal behavior being well documented, the involvement of lipid subtypes in the pathophysiology of impulsive and aggressive traits remains elusive. Further work is warranted to recognize the roles of lipids in neuronal membrane functions and serotonin metabolism, promote a greater appreciation of identifying biomarkers that could be used to determine at-risk individuals, and develop potential interventions to disrupt the pathogenesis of behavioral phenotypes of suicide.