PubMed2006
The major risk determinants of violence are to be young and male, to have low socioeconomic status and suffering substance abuse. This is true whether it occurs in the context of a concurrent mental illness or not; i.e., mental disorders are neither necessary, nor sufficient causes for violence. Intense motivation is a facilitating factor for violence in clinical and non clinical samples. This explains why 'normal' people, are implicated in planned violence at higher rates than mentally ill (e.g. in criminal acts against property). However mentally ill patients are more easily implicated in impulsive violence or in violence without obvious cause due to veiled motivation fuelled by unidentified symptoms. Subjective or real awareness of competitive disadvantage increases motivation for violence (e.g. paranoid, narcissistic symptoms, etc.). Many psychiatric disorders as antisocial disorder, borderline, schizophrenia, have most of the factors that facilitate the appearance of violence. Antisocial disorder is a good model to study determinants of violence in normal samples as it is present in young males that do not have any psychotic symptom, have stable symptomatology, self control under scrutiny, and their motivations are similar to normal samples. Our evolutionary model suggests that there is a non random association of genetic factors (genes, pseudogenes, promoting areas, etc.), that is, a genetic cluster (cluster DO), whose phylogenetic function is to motivate to be the dominant in social relationships. To be the dominant is a major psychological feature present in many social groups of animals, included primates. DO cluster have sense from an evolutionary viewpoint: when expressed in no pathological way it increases inclusive fitness (transmission of the genes of a person genotype whether by oneself or by relatives reproduction). Features of cluster DO in humans are expressed differently according to sex, age, moral education, level of intelligence, etc. Cluster DO has higher phenotypical expression in males and young people. Primary antisocial personality disorder and other related disorders (cluster B personality disorders, disocial, defiant disorder, etc.), are a pathological manifestation of this cluster DO. Some other genetic clusters that causes the genetic liability to some disorders (e.g. attention deficit disorder) are non random associated with cluster DO, thus explaining clinical comorbidity. According to our model, motivation for dominance usually prevails over motivation for material benefit or antinormative behaviour, this explains some incongruent behaviour in antisocial patients not elucidated by other models. Along with the primary expressed feature of dominance of cluster DO there are other secondary features that have been identified by psychobiological studies: novelty seeking, intolerance for frustration, impulsiveness, fearless, aggressiveness, higher threshold for activation of the sympathetic system, lack of empathy, egoism, non acceptance of rules, defiant and rebellious behaviour, manipulation in social interactions, selfishness and deficits in altruism or in social co-operation.