Although the ICD and DSM differentiate between different psychiatric disorders, these often share symptoms, risk factors, and treatments. This was a population-based, case–control, sibling study examining familial clustering of all psychiatric disorders and low IQ, using data from the Israel Draft-Board Registry on all Jewish adolescents assessed between 1998 and 2014.

We identified all cases with autism spectrum disorder (ASD, N = 2128), severe intellectual disability (ID, N = 9572), attention-deficit hyperactive disorder (ADHD) (N = 3272), psychotic (N = 7902), mood (N = 9704), anxiety (N = 10 606), personality (N = 24 816), or substance/alcohol abuse (N = 791) disorders, and low IQ (⩾2 SDs below the population mean, N = 31 186). Non-CNS control disorders were adolescents with Type-1 diabetes (N = 2427), hernia (N = 29 558) or hematological malignancies (N = 931). Each case was matched with 10 age-matched controls selected at random from the Draft-Board Registry, with replacement, and for each case and matched controls, we ascertained all full siblings. The main outcome measure was the relative recurrence risk (RRR) of the sibling of a case having the same (within-disorder RRR) or a different (across-disorder RRR) disorder.

Within-disorder RRRs were increased for all diagnostic categories, ranging from 11.53 [95% confidence interval (CI): 9.23–14.40] for ASD to 2.93 (95% CI: 2.80–3.07) for personality disorders. The median across-disorder RRR between any pair of psychiatric disorders was 2.16 (95% CI: 1.45–2.43); the median RRR between low IQ and any psychiatric disorder was 1.37 (95% CI: 0.93–1.98). There was no consistent increase in across-disorder RRRs between the non-CNS disorders and psychiatric disorders and/or low IQ.

These large population-based study findings suggest shared etiologies among most psychiatric disorders, and low IQ.

Personality disorders are prevalent in 6–10% of the population, but their risk for cause-specific mortality is unclear. The aim of the study was to assess the association between personality disorders diagnosed in late adolescence and all-cause as well as cause-specific (cardiovascular-related, external-related) mortality.

We performed a longitudinal study on a historical prospective cohort based on nationwide screening prior to recruitment to the Israeli army. The study participants were 16–19-year-old persons who attended the army screening (medical and cognitive, including screening for psychiatric disorders) between 1967 and 2006. Participants were followed from 1967 till 2011.

The study included 2 051 606 subjects, of whom 1 229 252 (59.9%) were men and 822 354 (40.1%) were women, mean age 17.36 years. There were 55 508 (4.5%) men and 8237 (1.0%) women diagnosed with personality disorders. The adjusted hazard ratio (HRs) for coronary, stroke, cardiovascular, external-related causes and all-cause mortality among men with personality disorders were 1.34 (1.03–1.74), 1.82 (1.20–2.76), 1.45 (1.23–1.71), 1.41 (1.30–1.53) and 1.44 (1.36–1.51), respectively. The absolute rate difference for all-cause mortality was 56.07 and 13.19 per 105 person-years among men and women, respectively. Among women with personality disorders, the adjusted HRs for external-related causes and all-cause mortality were 2.74 (1.87–4.00) and 2.01 (1.56–2.58). Associations were already evident within 10 years of follow-up.

Personality disorder in late adolescence is associated with increased risk of cardiovascular, external- and all-cause mortality. Increased cardiovascular mortality is evident before the age of 40 years and may point to the importance of lifestyle education already in youth.