Recent studies suggest psychotic and eating disorders can be comorbid and could have shared genetic liability. However, this comorbidity has been overlooked in the epidemiological literature.

To test whether polygenic risk scores (PRS) for schizophrenia are associated with disordered eating behaviours and body mass index (BMI) in the general population.

Using data from the Avon Longitudinal Study of Parents and Children and random-effects logistic and linear regression models, we investigated the association between PRS for schizophrenia and self-reported disordered eating behaviours (binge eating, purging, fasting and excessive exercise) and BMI at 14, 16 and 18 years.

Of the 6920 children with available genetic data, 4473 (64.6%) and 5069 (73.3%) had at least one disordered eating and one BMI outcome measurement, respectively. An s.d. increase in PRS was associated with greater odds of having binge eating behaviours (odds ratio, 1.36; 95% CI 1.16–1.60) and lower BMI (coefficient, −0.03; 95% CI, −0.06 to −0.01).

Our findings suggest the presence of shared genetic risk between schizophrenia and binge eating behaviours. Intermediate phenotypes such as impaired social cognition and irritability, previously shown to be positively correlated in this sample with schizophrenia PRS, could represent risk factors for both phenotypes. Shared genetic liability between binge eating and schizophrenia could also explain higher rates of metabolic syndrome in individuals with schizophrenia, as binge eating could be a mediator of this association in drug-naïve individuals. The finding of an association between greater PRS and lower BMI, although consistent with existing epidemiological and genetic literature, requires further investigation.

None.

Rates and risk factors for suicidal behaviour require updating and comparisons among mood disorders.

To identify factors associated with suicidal risk in major mood disorders.

We considered risk factors before, during and after intake assessments of 3284 adults with/without suicidal acts, overall and with bipolar disorder (BD) versus major depressive disorder (MDD), using bivariate comparisons, multivariable regression modelling and receiver operating characteristic (ROC) analysis.

Suicidal prevalence was greater in BD versus MDD: ideation, 29.2 versus 17.3%; attempts, 18.8 versus 4.78%; suicide, 1.73 versus 0.48%; attempts/suicide ratio indicated similar lethality, 10.9 versus 9.96. Suicidal acts were associated with familial BD or suicide, being divorced/unmarried, fewer children, early abuse/trauma, unemployment, younger onset, longer illness, more dysthymic or cyclothymic temperament, attention-deficit hyperactivity disorder (ADHD), substance misuse, mixed features, hospital admission, percentage time unwell, less antidepressants and more antipsychotics and mood stabilisers. Logistic regression found five independent factors: hospital admission, more depression at intake, BD diagnosis, onset age ≤25 years and mixed features. These factors were more associated with suicidal acts in BD than MDD: percentage time depressed/ill, alcohol misuse, >4 pre-intake depressions, more dysthymic/cyclothymic temperament and prior abuse/trauma. ADHD and total years ill were similar in BD and MDD; other factors were more associated with MDD. By ROC analysis, area under the curve was 71.3%, with optimal sensitivity (76%) and specificity (55%) with any two factors.

Suicidal risks were high in mood disorders: ideation was highest with BD type II, attempts and suicides (especially violent) with BD type I. Several risk factors for suicidal acts differed between BD versus MDD patients.

No author or immediate family member has financial relationships with commercial entities that might appear to represent potential conflicts of interest with the information presented.