Comorbid substance addiction and mental illness is highly prevalent and often results in negative treatment outcomes. For example, it is quite common for patients with dual diagnosis to drop-out of treatment. Identifying the origins of this and other possible negative outcomes can be crucial for treating addictive disorders.
Literature has showed that substance use is associated with a plethora of psychiatric symptoms and syndromes, such as anxiety, depression, eating disorders, stressorrelated disorders, and personality disorders, among others. In particular, rates of personality disorders in people with addictive disorders are exceptionally higher than in the general population. Just to make an example, the prevalence of borderline personality disorder in adult population is estimated at about 2.7% , and about 78% of people suffering from borderline personality disorder also develop a substance-related disorder or addiction at some time in their lives . Comorbid personality disorders may complicate the treatment of addicted patients: usually these patients show more severe patterns of substance use, and they even show social problems at a higher degree than
their peers without personality disorders, resulting in an elevated risk for non-completing treatment. Completion of addiction treatment, in turn, is one of the most consistent factors associated with a favorable treatment outcome .
Empirical studies on the role of personality disorders in substance addiction have focused primarily on borderline and antisocial personality disorders. However, almost the whole spectrum of personality disorders can be encountered in patients who suffer from addictive behaviors, including narcissistic, dependent, avoidant, and other personality disorders . In fact, clinical experience suggests that denial, deceitfulness and resistance to change are all potential barriers that are often encountered when treating patients with substance use. These barriers are likely the results of personality disorders and other dysfunctional personality traits, and they are mirrored in problems with therapeutic alliance, which in turn can precipitate a relapse to addictive behaviors thus preventing succesful treatment in many cases.
Research has already provided evidence for the importance of dysfunctional personality traits in the development of addictive disorders . especially in the domains of negative affectivity (e.g. emotional lability and separation insecurity) and disinhibition (impulsivity and risk taking). Therefore, the treatment of patients who suffer from addictive disorders could result more effective when personality disorders are also addressed. Luckily, knowledge about the effectiveness of dually focused treatments (i.e. treatments addressing both substance addiction and personality disorders) is slowly emerging , although integrated treatment programs are still lacking and research in this field continues to be limited.
Patients with substance addiction may need tailored clinical interventions that are able to promote their often underdeveloped affect regulation and mentalizing abilities . At the same time, other key variables must be considered and addressed for an effective treatment, such as compliance with therapy, treatment retention, and collapse of drug using patterns. This requires a careful assessment of patient’s personality disorders and dysfunctional personality traits. These can foster substance addiction, can disrupt the therapeutic alliance, and can even prevent a positive treatment outcome.
Clinical work still needs comprehensive models for the understanding and treatment of substance addiction based on personality and psychopathology research. I am confident that our Journal will be at the forefront of this research.