Relatively little is known of the use of systematic review and synthesis methods of non-randomised psychiatric epidemiological studies, which play a vital role in aetiological research, planning and policy-making.

To evaluate reviews of psychiatric epidemiological studies of functional mental disorders that employed synthesis methods such as systematic review or meta-analysis, or other forms of quantitative review.

We searched the literature to identify appropriate reviews published during the period 1996 to April 2009. Selected reviews were evaluated using published review guidelines.

We found 106 reviews in total, of which 38 (36%) did not mention method of data abstraction from primary studies at all. Many failed to mention study quality, publication bias, bias and confounding. In 73 studies that performed a meta-analysis, 58 (79%) tested for heterogeneity and of these, 47 found significant heterogeneity. Studies that detected heterogeneity made some allowance for this. A major obstacle facing reviewers is the wide variation between primary studies in the use of instruments to measure outcomes and in sampling methods used.

Many deficiencies found in systematic reviews are potentially remediable, although synthesis of primary study findings in a field characterised by so many sources of heterogeneity will remain challenging.

Mental and physical disorders are associated with total disability, but their effects on days with partial disability (i.e. the ability to perform some, but not full-role, functioning in daily life) are not well understood.

To estimate individual (i.e. the consequences for an individual with a disorder) and societal effects (i.e. the avoidable partial disability in the society due to disorders) of mental and physical disorders on days with partial disability around the world.

Respondents from 26 nationally representative samples (n = 61 259, age 18+) were interviewed regarding mental and physical disorders, and day-to-day functioning. The Composite International Diagnostic Interview, version 3.0 (CIDI 3.0) was used to assess mental disorders; partial disability (expressed in full day equivalents) was assessed with the World Health Organization Disability Assessment Schedule in the CIDI 3.0.

Respondents with disorders reported about 1.58 additional disability days per month compared with respondents without disorders. At the individual level, mental disorders (especially post-traumatic stress disorder, depression and bipolar disorder) yielded a higher number of days with disability than physical disorders. At the societal level, the population attributable risk proportion due to physical and mental disorders was 49% and 15% respectively.

Mental and physical disorders have a considerable impact on partial disability, at both the individual and at the societal level. Physical disorders yielded higher effects on partial disability than mental disorders.

People with 22q11.2 deletion syndrome (velo-cardio-facial syndrome) have a 30-fold risk of developing schizophrenia. In the general population the schizophrenia phenotype includes a cognitive deficit and a decline in academic performance preceding the first episode of psychosis in a subgroup of patients. Findings of cross-sectional studies suggest that cognitive abilities may decline over time in some children with 22q11.2 deletion syndrome. If confirmed longitudinally, this could indicate that one or more genes within 22q11.2 are involved in cognitive decline.

To assess longitudinally the change in IQ scores in children with 22q11.2 deletion syndrome.

Sixty-nine children with the syndrome were cognitively assessed two or three times at set ages 5.5 years, 7.5 years and 9.5 years.

A mean significant decline of 9.7 Full Scale IQ points was found between ages 5.5 years and 9.5 years. In addition to the overall relative decline that occurred when results were scored according to age-specific IQ norms, in 10 out of a group of 29 children an absolute decrease in cognitive raw scores was found between ages 7.5 years and 9.5 years. The decline was not associated with a change in behavioural measures.

The finding of cognitive decline can be only partly explained as the result of ‘growing into deficit’; about a third of 29 children showed an absolute loss of cognitive faculties. The results underline the importance of early psychiatric screening in this population and indicate that further study of the genes at the 22q11.2 locus may be relevant to understanding the genetic basis of early cognitive deterioration.

Prior research reports stronger associations between childhood maltreatment and adult psychopathology when maltreatment is assessed retrospectively compared with prospectively, casting doubt on the mental health risk conferred by maltreatment and on the validity of retrospective reports.

To investigate associations of psychopathology with prospective v. retrospective maltreatment ascertainment.

A nationally representative sample of respondents aged 16–27 years (n = 1413) in New Zealand completed a retrospective assessment of maltreatment and DSM-IV mental disorders. Survey data were linked with a national child protection database to identify respondents with maltreatment records (prospective ascertainment).

Childhood maltreatment was associated with elevated odds of mood, anxiety and drug disorders (odds ratios = 2.1–4.1), with no difference in association strength between prospective and retrospective groups. Prospectively ascertained maltreatment predicted unfavourable depression course involving early onset, chronicity and impairment.

Prospectively and retrospectively assessed maltreatment elevated the risk of psychopathology to a similar degree. Prospectively ascertained maltreatment predicted a more unfavourable depression course.

Inconsistent findings have been reported on the role of comorbid alcohol use disorders as risk factors for a persistent course of depressive and anxiety disorders.

To determine whether the course of depressive and/or anxiety disorders is conditional on the type (abuse or dependence) or severity of comorbid alcohol use disorders.

In a large sample of participants with current depression and/or anxiety (n = 1369) we examined whether the presence and severity of DSM-IV alcohol abuse or alcohol dependence predicted the 2-year course of depressive and/or anxiety disorders.

The persistence of depressive and/or anxiety disorders at the 2-year follow-up was significantly higher in those with remitted or current alcohol dependence (persistence 62% and 67% respectively), but not in those with remitted or current alcohol abuse (persistence 51% and 46% respectively), compared with no lifetime alcohol use disorder (persistence 53%). Severe (meeting six or seven diagnostic criteria) but not moderate (meeting three to five criteria) current dependence was a significant predictor as 95% of those in the former group still had a depressive and/or anxiety disorder at follow-up. This association remained significant after adjustment for severity of depression and anxiety, psychosocial factors and treatment factors.

Alcohol dependence, especially severe current dependence, is a risk factor for an unfavourable course of depressive and/or anxiety disorders, whereas alcohol abuse is not.

Climate change is expected to have significant effects on human health, partly through an increase in extreme events such as heatwaves. People with mental illness may be at particular risk.

To estimate risk conferred by high ambient temperature on patients with psychosis, dementia and substance misuse.

We applied time-series regression analysis to data from a nationally representative primary care cohort study. Relative risk of death per 1° increase in temperature was calculated above a threshold.

Patients with mental illness showed an overall increase in risk of death of 4.9% (95% CI 2.0–7.8) per 1° increase in temperature above the 93rd percentile of the annual temperature distribution. Younger patients and those with a primary diagnosis of substance misuse demonstrated greatest mortality risk.

The increased risk of death during hot weather in patients with psychosis, dementia and substance misuse has implications for public health strategies during heatwaves.

Visual hallucinations and visuoperceptual deficits are common in dementia with Lewy bodies, suggesting that cortical visual function may be abnormal.

To investigate: (1) cortical visual function using functional magnetic resonance imaging (fMRI); and (2) the nature and severity of perfusion deficits in visual areas using arterial spin labelling (ASL)-MRI.

In total, 17 participants with dementia with Lewy bodies (DLB group) and 19 similarly aged controls were presented with simple visual stimuli (checkerboard, moving dots, and objects) during fMRI and subsequently underwent ASL-MRI (DLB group n = 15, control group n = 19).

Functional activations were evident in visual areas in both the DLB and control groups in response to checkerboard and objects stimuli but reduced visual area V5/MT (middle temporal) activation occurred in the DLB group in response to motion stimuli. Posterior cortical perfusion deficits occurred in the DLB group, particularly in higher visual areas.

Higher visual areas, particularly occipito-parietal, appear abnormal in dementia with Lewy bodies, while there is a preservation of function in lower visual areas (V1 and V2/3).

Many specialty-specific functional somatic syndrome diagnoses exist to describe people who are experiencing so-called medically unexplained symptoms. Although cognitive–behavioural therapy can be effective in the management of such syndromes, it is rarely available. A cognitive–behavioural therapy suitable for group treatment of people with different functional somatic syndromes could address this problem.

To test the efficacy of a cognitive–behavioural therapy (Specialised Treatment for Severe Bodily Distress Syndromes, STreSS) designed for patients with a range of severe functional somatic syndromes.

A randomised controlled trial (clinicaltrials.gov, NCT00132197) compared STreSS (nine 3.5 h sessions over 4 months, n = 54) with enhanced usual care (management by primary care physician or medical specialist, n = 66). The primary outcome was improvement in aggregate score on subscales of the 36-item Short Form Health Survey (physical functioning, bodily pain and vitality) at 16 months.

Participants receiving STreSS had a greater improvement on the primary outcome (adjusted mean difference 4.0, 95% CI 1.4–6.6, P = 0.002) and on most secondary outcomes.

In the management of functional somatic syndromes, a cognitive–behavioural group treatment was more effective than enhanced usual care.