Homicide and suicide: biology and psychopathology

Abstract

Introduction: We aim to highlight and contribute to elucidate extreme violence entailed by homicide and suicide regarding the corresponding psycho-neuro-biological substrates.

Material and method: The databases PubMed/Medline, Scilit-Scientific Literature and others have been examined. The literature that we found is varied and immense. Because of that, we have chosen to conduct a narrative review as updated as possible.

Results and discussion: In addition to the most psychologistic approaches, extreme violence has been related to epigenetic mechanisms such as DNA methylation. Anatomo-physiological tracts linked to oxytocin may contribute to the individual differences in the physiological and molecular consequences of exposure to violence. The determination of the messenger RNA of the enzyme “Histone Deacetylase-1” in the mononuclear cells seems to be important, since it intervenes in epigenetic processes. Regarding suicide in particular, familiar addition of the suicidal behaviours related to one-nucleotide polymorphisms has also been found, indicating genetic transmission. People who commited suicide had a greater genetic risk of behavioural lack of inhibition and certain mental disorders. There is a neural correlative between suicidal behaviours or thoughts and the reduction of the thickness of the superior temporal convolution. The MAO genetic and enzymatic system is also involved.

Conclusion: The biological foundations of homicidal and, above all, suicidal behaviours are undeniable. The related scientific information is very prolix and generally is based on small samples. Therefore, further quality studies are required in order to properly determine the biological and molecular changes associated with such behaviours.