31st January 2024

Comorbidities and Differential Diagnoses

In many instances, a comorbidity can be difficult to be distinguished from a differential diagnosis. Even the diagnostic criteria for some of the psychiatric disorders can cross over from one diagnosis to another, and personality disorders are no exception to this.

Co-occurring Physical Health Illnesses

There is an inter-relationship between different types of personality disorders and chronic physical health illnesses like gastrointestinal disease, cardiovascular disease, obesity, chronic pain and sleep disturbance. Asthma, Rheumatism and musculoskeletal problems are among the reported physical health comorbidities.

Mood Disorders

• Bipolar disorder, depression and dysthymia are thought to be the most commonly studied mood disorders in relation to a comorbid personality disorder. 
• Cluster A personality disorders are thought to be the least likely to be comorbid with mood disorders.
• Cluster C personality disorders are thought to be the most likely to be comorbid with mood disorders. 

Anxiety

Generalised anxiety disorder, PTSD, OCD, phobia and other anxiety disorders commonly present with different personality disorders. Cluster C is the most commonly seen cluster co-occurring with anxiety disorders.

ADHD

Antisocial and borderline personality disorders appear to be the most commonly co-occurring personality disorders with ADHD.

Eating Disorders

Both anorexia nervosa and bulimia nervosa have been reported to occur in similar rates in different personality disorders, especially in borderline and avoidant personality disorders. Only obsessive-compulsive personality disorder has shown higher incidence of anorexia nervosa than bulimia nervosa.

Schizophrenia and Psychotic Disorders

Cluster A has been linked to schizophrenia for years. In the ICD-11, the schizotypal personality disorder is referred to as schizotypal disorder and is no longer a personality disorder, but it comes under “Schizophrenia or other primary psychotic disorders”.

Alcohol and Substance Use

Antisocial and borderline personality disorders are frequently reported in individuals who have substance use disorder.

Complex PTSD (CPTSD)

This is a new ICD-11 diagnosis, which includes the already known symptoms of PTSD of re-experiencing trauma (flashbacks and nightmares), avoidance of stimuli that could act as reminders for the original trauma and hypervigilance. In addition to these, CPTSD has additional complex reaction in 3 main domains:  emotion regulation, self-identity and relational capacities. This new diagnosis has some similarities and overlap with borderline personality disorder, especially since both happen in people who experience traumatic events. A key difference between both is that an individual with CPTSD would have severe yet stable negative self-concept in contrast to someone with borderline personality disorder who would experience a shift in their self-image.

References

• Semple D, Smyth R. Oxford handbook of psychiatry. Oxford University Press; 2019 Jul 30.
• Dixon-Gordon KL, Conkey LC, Whalen DJ. Recent advances in understanding physical health problems in personality disorders. Current opinion in psychology. 2018 Jun 1;21:1-5.
• Friborg O, Martinsen EW, Martinussen M, Kaiser S, Øvergård KT, Rosenvinge JH. Comorbidity of personality disorders in mood disorders: a meta-analytic review of 122 studies from 1988 to 2010. Journal of affective disorders. 2014 Jan 1;152:1-1.
• Latas M, Milovanovic S. Personality disorders and anxiety disorders: what is the relationship?. Current opinion in psychiatry. 2014 Jan 1;27(1):57-61.
• Martinussen M, Friborg O, Schmierer P, Kaiser S, Øvergård KT, Neunhoeffer AL, Martinsen EW, Rosenvinge JH. The comorbidity of personality disorders in eating disorders: a meta-analysis. Eating and Weight Disorders-Studies on Anorexia, Bulimia and Obesity. 2017 Jun;22(2):201-9.
• Cloitre M. ICD-11 complex post-traumatic stress disorder: Simplifying diagnosis in trauma populations. The British journal of psychiatry. 2020 Mar;216(3):129-31.