Although psychotic experiences in people without diagnosed mental health problems are associated with mental health service use, few studies have assessed this prospectively or measured service use by real-world clinical data.

To describe and investigate the association between psychotic experiences and later mental health service use, and to assess the role of symptoms of common mental health disorders in this association.

We linked a representative survey of south-east London (SELCoH-1, n=1698) with health records from the local mental healthcare provider. Cox regression estimated the association of PEs with rate of mental health service use.

After adjustments, psychotic experiences were associated with a 1.75-fold increase in the rate of subsequent mental health service use (hazard ratio (HR) 1.75, 95% CI 1.03–2.97) compared with those without PEs. Participants with PEs experienced longer care episodes compared with those without.

Psychotic experiences in the general population are important predictors of public mental health need, aside from their relevance for psychoses. We found psychotic experiences to be associated with later mental health service use, after accounting for sociodemographic confounders and concurrent psychopathology.

Hypomanic symptoms may be a useful predictor of mood disorder among young people at high risk for bipolar disorder.

To determine whether hypomanic symptoms differentiate offspring of parents with bipolar disorder (high risk) and offspring of well parents (control) and predict the development of mood episodes.

High-risk and control offspring were prospectively assessed using semi-structured clinical interviews annually and completed the Hypomania Checklist-32 Revised (HCL-32). Clinically significant sub-threshold hypomanic symptoms (CSHS) were coded.

HCL-32 total and active or elated scores were higher in control compared with high-risk offspring, whereas 14% of high-risk and 0% of control offspring had CSHS. High-risk offspring with CSHS had a fivefold increased risk of developing recurrent major depression (P=0.0002). The median onset of CSHS in high-risk offspring was 16.4 (6–31) years and was before the onset of major mood episodes.

CSHS are precursors to major mood episodes in high-risk offspring and could identify individuals at ultra-high risk for developing bipolar disorder.

The psychiatric health burden of prisoners is substantial. However, there is a lack of high-quality studies of psychiatric disorders among young adults with a high risk of reoffending.

To investigate the lifetime prevalence of psychiatric disorders and use of mental health services among young male violent offenders and the impact of childhood-onset conduct disorder (COCD).

A nationally representative cohort (n = 270, age 18–25) of male offenders was followed back in medical records and clinically assessed by gold standard methods. Lifetime prevalences are presented together with odds ratios (ORs) as risk estimates in relation to COCD.

Previous use of psychiatric services among the participants was high but their lifetime psychiatric morbidity was even higher, with 93% meeting criteria for at least one Axis I disorder. The COCD group was overrepresented in most clinical categories and carried five times higher odds (OR = 5.1, 95% CI 2.0–12.8) of a psychotic disorder, three times higher odds (OR = 3.2, 95% CI 1.2–8.5) of a substance use disorder and two times higher odds of a mood disorder (OR = 2.3, 95% CI 1.3–4.0) or anxiety disorder (OR = 2.0, 95% CI 1.1–3.5).

The mental health burden is substantial among young violent offenders, and COCD is an important indicator of future mental health problems which must be a priority for public health efforts.

There is growing interest in linking vitamin D deficiency with autism spectrum disorders (ASDs). The association between vitamin D deficiency during gestation, a critical period in neurodevelopment, and ASD is not well understood.

To determine the association between gestational vitamin D status and ASD.

Based on a birth cohort (n=4334), we examined the association between 25-hydroxyvitamin D (25OHD), assessed from both maternal mid-gestation sera and neonatal sera, and ASD (defined by clinical records; n=68 cases).

Individuals in the 25OHD-deficient group at mid-gestation had more than twofold increased risk of ASD (odds ratio (OR)=2.42, 95% confidence interval (CI) 1.09 to 5.07, P=0.03) compared with the sufficient group. The findings persisted in analyses including children of European ethnicity only.

Mid-gestational vitamin D deficiency was associated with an increased risk of ASD. Because gestational vitamin D deficiency is readily preventable with safe, inexpensive and readily available supplementation, this risk factor warrants closer scrutiny.

Unidentified depression in primary care is a public health concern, globally. There is a need for brief, valid and easily administered tools in primary care.

To estimate reliability and validity of the newly developed Primary care Screening Questionnaire for Depression (PSQ4D), a four-item tool, with ‘yes’ or ‘no’ options.

PSQ4D was administered verbally (time required, <1 min) by primary care physicians to adult outpatients (n=827) in six primary care settings in Kerala, India. A psychiatrist evaluated each patient on the same day, using ICD-10 Diagnostic Criteria for Research, based on unstructured clinical interview.

The Cronbach's alpha for internal consistency reliability was 0.80; kappa coefficient for test-retest reliability was 0.9 and that for interrater reliability was 0.72. At a score ≥2, sensitivity was 0.96, specificity was 0.87, positive predictive value was 0.74, negative predictive value was 0.98, positive likelihood ratio was 7.4 and negative likelihood ratio was 0.05.

When physician administered, PSQ4D has good reliability. At a cut-off score of ≥2, it has high sensitivity and specificity to identify depressive disorder in primary care.