The global epidemiology of personality disorder: a systematic review and meta-regression

Background
Personality disorder is a persistent and pervasive mental disorder, defined as an enduring pattern of inner experience and behaviour that deviates markedly from the expectations of an individual's culture, but it remains under-recognised in global mental health estimates. To our knowledge, no comprehensive synthesis has quantified the global prevalence, mortality, or diagnostic stability of personality disorder using population-representative data. We aimed to address these gaps to support future burden of disease modelling.

Methods
We conducted a systematic review and meta-regression of population-based surveys following PRISMA and GATHER guidelines. Eligible studies were cross-sectional or longitudinal studies published in peer-reviewed journals that reported prevalence or mortality associated with any personality disorder using DSM or ICD diagnostic criteria on representative samples. Personality disorder encompassed paranoid, schizoid, schizotypal, antisocial, borderline, histrionic, narcissistic, avoidant, dependent, obsessive-compulsive, and other specified and unspecified personality disorders. Studies using self-report instruments and non-representative samples (eg, clinical, incarcerated, or university populations) were excluded. Studies were identified through systematic searches in PubMed, Embase, and PsycINFO from Jan 1, 1980, to Feb 13, 2024. Studies were reviewed (by JS and a research assistant), and eligible data were extracted by JS. All data were non-identifiable and pre-aggregated from existing sources. Study quality was assessed using Joanna Briggs Institute critical appraisal tools. Due to data availability, we did two separate meta-regression analyses to estimate the prevalence and standardised mortality ratios associated with personality disorder, and a descriptive analysis to examine diagnostic stability. Between-study heterogeneity was assessed using the I2 statistic. Meta-regression models assessed the effect of study-level covariates. Members of our authorship team have lived personal experience with mental disorders, but we did not consult individuals diagnosed with personality disorder for this work. The study is registered with PROSPERO, CRD42021269169.

Findings
We identified 60 studies across 28 countries. Prevalence analyses included 139 373 individuals, and mortality analyses included 392 420 individuals with a personality disorder. Between-study heterogeneity was high for prevalence (I2=98<middle dot>8%) and mortality (I2=99<middle dot>4%). Study quality assessment indicated that 59 studies were of high quality, with only one study of moderate quality. Pooled prevalence of any personality disorder ranged from 4<middle dot>1% (95% uncertainty interval [UI] 2<middle dot>8-6<middle dot>0) in low-income and middle-income countries to 5<middle dot>2% (3<middle dot>7-7<middle dot>3) in high-income countries for mid-age 43 years. Prevalence was found to be higher among male individuals (compared with female individuals) and to decrease with age. Meta-regression results identified heterogeneity linked to diagnostic criteria, interviewer type, and region. Publication bias was identified in prevalence analyses. Personality disorder was associated with elevated mortality, with pooled standardised mortality ratios of 4<middle dot>7 (95% UI 3<middle dot>7-5<middle dot>8) for inpatients, 1<middle dot>8 (1<middle dot>4-2<middle dot>2) for outpatients, and 2<middle dot>2 (1<middle dot>8-2<middle dot>9) for both inpatients and outpatients. Data indicated that personality disorder shows moderate diagnostic stability over time. Interpretation Personality disorder is common, associated with premature mortality, and diagnostically stable, yet remains excluded from the Global Burden of Diseases, Injuries, and Risk Factors Study. We provide a comprehensive synthesis of personality disorder epidemiology, offering the foundation needed to inform future global estimates and policy responses.