31st January 2024

Overview

The concept of personality has been explored since the dawn of human existence. The “4 humours theory” is probably the first known recognised categorisation, which is seen in Hippocrates’ teaching. This theory states that 4 bodily fluids/humours should be balanced for someone to be healthy. The 4 fluids are black bile, yellow bile, blood and phlegm. Galen, a disciple of Hippocrates, linked these 4 humours to personality. Later, Theophrastus described 30 characters to group people under.

By the end of adolescence and the beginning of adulthood, our personality reaches a level of stability. Someone with personality disorder is essentially characterised by a pervasive and chronic pattern of a set of behaviours and ideas leading to a certain level of rigidity in situations to which other people without a personality disorder can adapt to. Many factors contribute to the development and formation of one’s personality, including genetic, environmental and psychological factors. This indicates that both “nature” and “nurture” drive the formation of a personality disorder.

There is some evidence that some personality disorders may be associated with structural brain deficits. Antisocial personality disorder demonstrates reduction in the volume of prefrontal grey matter. Borderline personality disorder shows higher left amygdala activation to facial expressions of emotion compared controls. Some other studies showed that there is evidence of reduced volume in the frontal lobe, bilateral hippocampus, bilateral amygdala, left orbitofrontal cortex, right anterior cingulate cortex, and right parietal cortex and increased putamen volume in borderline personality disorder.

In terms of treatment, there are no drugs licensed for treatment of any of the personality disorders, so the main lines of treatment are psychological interventions and lifestyle modifications. However, medications can always be used in treating comorbidities of personality disorders. 

References

• Tyrer P, Mulder R. Personality disorder: from evidence to understanding. Cambridge University Press; 2022 Feb 24. 
• Raine A, Lencz T, Bihrle S, LaCasse L, Colletti P. Reduced prefrontal gray matter volume and reduced autonomic activity in antisocial personality disorder. Archives of general psychiatry. 2000 Feb 1;57(2):119-27.
• Donegan NH, Sanislow CA, Blumberg HP, Fulbright RK, Lacadie C, Skudlarski P, Gore JC, Olson IR, McGlashan TH, Wexler BE. Amygdala hyperreactivity in borderline personality disorder: implications for emotional dysregulation. Biological psychiatry. 2003 Dec 1;54(11):1284-93.
• Lis E, Greenfield B, Henry M, Guilé JM, Dougherty G. Neuroimaging and genetics of borderline personality disorder: a review. Journal of Psychiatry and Neuroscience. 2007 May 1;32(3):162-73.