A better understanding of PD-Sx can therefore improve not only the management of PDs, but potentially also that of comorbid psychiatric disorders. For this reason, PD symptoms are more prevalent in psychiatric populations ( Bagby et al., 2008 Grant et al., 2012), and can present risk factors for emergence of additional psychiatric disorders and/or barriers to treatment. Even in the absence of a formal PD diagnosis, personality traits reflecting PD symptomatology (PD-Sx) can lead to emotional and interpersonal problems (e.g., Daley et al., 2000 Rosenthal et al., 2005 Dick et al., 2013 Gervais et al., 2013), and are often comorbid with major psychiatric conditions (DSM-IV Axis I disorders), particularly substance use, mood, and anxiety disorders ( Daley et al., 1999 Chabrol et al., 2004 Hallquist and Lenzenweger, 2013). Personality disorders are enduring, pervasive, and inflexible patterns of inner experience and behavior that deviate from cultural expectations and lead to distress or impairment.
In addition, the observations parallel those in substance use disorders, pointing to the importance of considering PD-Sx when interpreting findings in often-comorbid psychiatric disorders. The results point to morphological abnormalities that could contribute to Cluster C PD-Sx. Both Cluster B and C PD-Sx groups also showed trends toward greater posterior caudate volumes and orbitofrontal surface area anomalies, but these findings did not survive correction for multiple comparisons.
Compared to control, Cluster C PD-Sx was associated with greater striatal surface area localized to the caudate tail, smaller ventral striatum volumes, and greater cortical thickness in right prefrontal cortex. Subjects reporting PD-Sx were then grouped into symptom-based clusters: N = 20 into Cluster B (reporting Antisocial, Borderline, Histrionic, or Narcissistic PD-Sx) and N = 28 into Cluster C (reporting Obsessive–Compulsive, Avoidant, or Dependent PD-Sx) N = 11 subjects reported PD-Sx from both clusters, and none reported Cluster A (Paranoid, Schizoid, or Schizotypal) PD-Sx. We investigated 37 subjects who reported PD-Sx exceeding DSM-IV Axis-II screening thresholds, and 35 age, sex, and smoking status-matched control subjects. To investigate brain morphological correlates of PD-Sx, we measured subcortical volume and shape, and cortical thickness/surface area, based on structural magnetic resonance images. Personality disorder symptomatology (PD-Sx) can result in personal distress and impaired interpersonal functioning, even in the absence of a clinical diagnosis, and is frequently comorbid with psychiatric disorders such as substance use, mood, and anxiety disorders however, they often remain untreated, and are not taken into account in clinical studies. 9Department of Psychiatry and Biomedical Engineering, McGill University, Montreal, QC, Canada.8Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada.7Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.6Complex Mental Illness Program, Forensic Service, Centre for Addiction and Mental Health, Toronto, ON, Canada.5Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.4Cerebral Imaging Centre, Douglas Mental Health University Institute, Verdun, QC, Canada.3Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
2Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.1Addictions Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.