We aimed to examine the temporal relationships between traumatic events (TE), post-traumatic stress disorder (PTSD) and non-affective psychotic disorders (NAPD).

A prospective cohort study of 1 965 214 individuals born in Sweden between 1971 and 1990 examining the independent effects of interpersonal and non-interpersonal TE on incidence of PTSD and NAPD using data from linked register data (Psychiatry-Sweden). Mediation analyses tested the hypothesis that PTSD lies on a causal pathway between interpersonal trauma and NAPD.

Increasing doses of interpersonal and non-interpersonal TE were independently associated with increased risk of NAPD [linear-trend incidence rate ratios (IRR)adjusted = 2.17 [95% confidence interval (CI) 2.02–2.33] and IRRadjusted = 1.27 (95% CI 1.23–1.31), respectively]. These attenuated to a relatively small degree in 5-year time-lagged models. A similar pattern of results was observed for PTSD [linear-trend IRRadjusted = 3.43 (95% CI 3.21–3.66) and IRRadjusted = 1.45 (95% CI 1.39–1.50)]. PTSD was associated with increased risk of NAPD [IRRadjusted = 8.06 (95% CI 7.23–8.99)], which was substantially attenuated in 5-year time-lagged analyses [IRRadjusted = 4.62 (95% CI 3.65–5.87)]. There was little evidence that PTSD diagnosis mediated the relationship between interpersonal TE and NAPD [IRRadjusted = 0.92 (percentile CI 0.80–1.07)].

Despite the limitations to causal inference inherent in observational designs, the large effect-sizes observed between trauma, PTSD and NAPD in this study, consistent across sensitivity analyses, suggest that trauma may be a component cause of psychotic disorders. However, PTSD diagnosis might not be a good proxy for the likely complex psychological mechanisms mediating this association.

Deficits in social cognition (the ability to recognise and understand emotions, intentions and actions in oneself and in others) have been found in people with post-traumatic stress disorder (PTSD). Few studies so far have examined whether social cognitive ability impacts on PTSD recovery. Here we present a protocol and preliminary data for a study that aims to evaluate whether pre-treatment social cognitive deficits are associated with treatment outcomes following trauma-focused therapy for PTSD.

The protocol was developed after discussion with Patient and Public Involvement (PPI) groups, and a battery of social cognitive tasks was trialled on 20 participants without PTSD. The final protocol was then developed using information and feedback from these preliminary studies. We aim to recruit 60 individuals who are about to start a trauma-focused therapy for PTSD within the two tertiary PTSD services. Social cognition (measured using a variety of tasks including Reading the Mind in the Eyes Task and the Reflective Functioning Questionnaire) and potential confounders (including severity of trauma history, attachment and verbal IQ) are assessed at baseline, prior to the start of therapy. PTSD symptom severity (measured using the PCL-5) and daily functioning (measured using the WSAS) are assessed pre and post-treatment. The primary aim of the study is to examine whether baseline social cognition is associated with the degree of improvement in the PCL-5.

So far 29 participants have been recruited and consented. 6 participants have completed follow-up assessments. The study has been adapted for the COVID-19 pandemic so participants can complete the tasks remotely. Preliminary results show a moderate negative correlation between baseline social cognitive abilities and baseline PTSD symptom severity (Spearman's correlation -0.30) and functional abilities (Spearman's correlation -0.42).

Development of our study in collaboration with PPI and preliminary testing of measures suggests it is likely that it will be feasible for us to conduct this study in this patient group. Baseline preliminary results show/suggest a moderate correlation between PTSD symptom severity and social cognitive impairment. Our main analyses, when completed, will help to determine whether social cognitive ability is associated with recovery from PTSD.

UK Biobank is a well-characterised cohort of over 500 000 participants including genetics, environmental data and imaging. An online mental health questionnaire was designed for UK Biobank participants to expand its potential.

Describe the development, implementation and results of this questionnaire.

An expert working group designed the questionnaire, using established measures where possible, and consulting a patient group. Operational criteria were agreed for defining likely disorder and risk states, including lifetime depression, mania/hypomania, generalised anxiety disorder, unusual experiences and self-harm, and current post-traumatic stress and hazardous/harmful alcohol use.

A total of 157 366 completed online questionnaires were available by August 2017. Participants were aged 45–82 (53% were ≥65 years) and 57% women. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status. Lifetime depression was a common finding, with 24% (37 434) of participants meeting criteria and current hazardous/harmful alcohol use criteria were met by 21% (32 602), whereas other criteria were met by less than 8% of the participants. There was extensive comorbidity among the syndromes. Mental disorders were associated with a high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation.

The UK Biobank questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed because of selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health.

UK Biobank is a well-characterised cohort of over 500 000 participants that offers unique opportunities to investigate multiple diseases and risk factors.

An online mental health questionnaire completed by UK Biobank participants was expected to expand the potential for research into mental disorders.

An expert working group designed the questionnaire, using established measures where possible, and consulting with a patient group regarding acceptability. Case definitions were defined using operational criteria for lifetime depression, mania, anxiety disorder, psychotic-like experiences and self-harm, as well as current post-traumatic stress and alcohol use disorders.

157 366 completed online questionnaires were available by August 2017. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status than the general population across a range of indicators. Thirty-five per cent (55 750) of participants had at least one defined syndrome, of which lifetime depression was the most common at 24% (37 434). There was extensive comorbidity among the syndromes. Mental disorders were associated with high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation.

The questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed owing to selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health.

G.B. received grants from the National Institute for Health Research during the study; and support from Illumina Ltd. and the European Commission outside the submitted work. B.C. received grants from the Scottish Executive Chief Scientist Office and from The Dr Mortimer and Theresa Sackler Foundation during the study. C.S. received grants from the Medical Research Council and Wellcome Trust during the study, and is the Chief Scientist for UK Biobank. M.H. received grants from the Innovative Medicines Initiative via the RADAR-CNS programme and personal fees as an expert witness outside the submitted work.

Comorbid post-traumatic stress disorder (PTSD) is associated with poorer outcomes of other disorders, but is treatable.

To estimate the frequency of clinically undetected PTSD in secondary care.

A systematic review of studies that screened for PTSD and reported on PTSD documentation in clinical records. Frequency of undetected PTSD was estimated, and reasons for heterogeneity explored.

The median proportion of participants with undetected PTSD (29 studies) was 28.6% (interquartile range 18.2–38.6%). There was substantial heterogeneity, with studies conducted in the USA and those with the highest proportions of in-patients and patients with psychotic disorder reporting higher frequencies of undetected PTSD.

Undetected PTSD is common in secondary care, even if the true value is at the lower limit of the estimates reported here. Trials examining the impact of routine screening for PTSD are required to determine whether such programmes should be standard procedure for all mental health services.

None.