Neuroscience of Aggression….can science provide answers?

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There has been much interest in whether there is a scientific basis to aggression or antisocial behaviors.  Prevailing knowledge has promoted the concept of hypo-frontality, which means that there is reduced brain activity in the decision-making part of the brain.  A recent paper that that appeared in JAMA Psychiatry by Drs. Jack Rogers and Stephane De Brito (Cortical and Subcortical Gray Matter Volume in Youth with Conduct Problems) seems to expand on this concept. In that paper, not only was there reduced grey matter (i.e., brain cells) in the pre-frontal cortex, which would impair decision-making but also in the amygdala (which processes strong emotions like fear and aggression) and association areas like the insula.  Basically, a person with these brain deficits would not process the usual halting processes that limit aggression, like being able to read fear or discomfort in the face of others, but also would show less empathy for the suffering of others.


There are, however, many unanswered questions.  Are individuals with pathological levels of aggression or anti-social behavior predisposed genetically to these brain abnormalities or can the behaviors themselves result in downstream effects to alter gene expression related to neuronal functioning, or a combination of both?  And are these structural brain changes directly correlated with aberrations in neuronal function?  Brain function and behavior are linked inextricably. We do know that experiencing violence or abuse, especially in childhood is a predisposing factor to the later development of anti-social or aggressive behaviors.  Basically, in many cases, experiencing profound violence or abuse in childhood can beget violence or anti-social behaviors in later life. Even earlier insults to the brain during pregnancy can have an impact. For instance, smoking and substance abuse during pregnancy may increase vulnerability in later life to being aggressive or anti-social. Pregnant mothers should avoid such behaviors or seek appropriate treatment for them if they pre-exist.


As a forensic expert, I am often called to evaluate whether an individual’s aggressive or anti-social behavior is the result of a mental disorder associated with personality or more overt mental illness (e.g. like hear voices, paranoia, or seeing things that do not exist).  Essentially, this might be more of a distinction of terms, and severity, as mental disorders can, generally, be associated with brain dysfunction, irrespective of its underpinnings.  Notably, however, there is a general difference in the long-term outcomes.  Generally, those that become aggressive or anti-social by virtue of personality factors have a more uncertain course of rehabilitation than others whose violent tendencies associated with the treatment of a mental disorder is more likely to abate. There is, however, no fixed rule.  I do caution here however, that most violenct or aggressive acts are not perpetrated by individuals with a mental disorder, and that having a mental disorder is generally associated with a marginally increased risk of aggression.


As a parent, I have wondered often how to instill in my own children behaviors that would make them more sensitive to the needs of others, and make them well balanced human beings as they grow up.  There is, however, no magic formula or secret sauce. With respect to environmental factors, even pre-verbal children code both positive and negative experiences in a way that modulates future gene expression. Basically, doing what you can as a parent to keep your kids happy and to show them love can have important benefits in later life.  It is important as a parent to engage in making the play experiences of your child or children positive, foster happiness and collaboration, and step-in to prevent any bullying or overtly aggressive behaviors. We know that it is unlikely that a stressful childhood is at all helpful in terms of later social and behavioral development and adjustment, even though some children, rather exceptionally, can develop resilience.  In other words, a loving childhood makes for better adjusted adults.  Whilst some cling to the notion of “tough love” in rearing there is little in the way of empirical scientific evidence that would support this approach to raise children who themselves do not become perpetrators of aggression or anti-social behavior.


Of course, we do not live in an ideal or prefect world, and not every child will have the most supportive childhood.  Nevertheless, the knowledge that even though our brains start developing from birth but do not actually reach their correct location and do not form the most enduring associations until early adult life should be comforting.  In essence, providing a nurturing environment as early as possible in a child’s life is most helpful to foster socially appropriate behaviors., And for those that miss out on a happy, loving, and supportive childhood, the motto should be never to give up and try to provide as much of this as possible in adolescence and into adult life.  Our brains are complex, and unlike previous theories, we know that it is in constant development until our very last day.  So, always seize the opportunity to encourage “positive” experiences – it is good for the brain.   Not only can the brain be nourished with the “right” foods and beverages but also with love, understanding, and support.2nii9hfjqw