The neurobiological underpinnings of attention deficit hyperactivity disorder (ADHD) are inconclusive. Activation abnormalities across brain regions in ADHD compared with healthy controls highlighted in task-based functional magnetic resonance imaging (fMRI) studies are heterogeneous. To identify a consistent pattern of neural dysfunction in ADHD, a meta-analysis of fMRI studies using Go/no-go, Stop and N-back tasks was undertaken.

Several databases were searched using the key words: ‘ADHD and fMRI’ and ‘ADHD and fMRI task’. In all, 20 studies met inclusion criteria comprising 334 patients with ADHD and 372 healthy controls and were split into N-back, Stop task and Go/no-go case–control groups. Using Signed Differential Mapping each batch was meta-analysed individually and meta-regression analyses were used to examine the effects of exposure to methylphenidate (MPH), length of MPH wash-out period, ADHD subtype, age and intelligence quotient (IQ) differences upon neural dysfunction in ADHD.

Across all tasks less activity in frontal lobe regions compared with controls was detected. Less exposure to treatment and lengthier wash-out times resulted in less left medial frontal cortex activation in N-back and Go/no-go studies. Higher percentage of combined-type ADHD resulted in less superior and inferior frontal gyrus activation. Different IQ scores between groups were linked to reduced right caudate activity in ADHD.

Consistent frontal deficits imply homogeneous cognitive strategies involved in ADHD behavioural control. Our findings suggest a link between fMRI results and the potentially normalizing effect of treatment and signify a need for segregated examination and contrast of differences in sample characteristics in future studies.

Healthy older adults report greater well-being and life satisfaction than their younger counterparts. One potential explanation for this is enhanced optimism. We tested the influence of age on optimistic and pessimistic beliefs about the future and the associated structural neural correlates.

Eighteen young and 18 healthy older adults performed a belief updating paradigm, measuring differences in updating beliefs for desirable and undesirable information about future negative events. These measures were related to regional brain volume, focusing on the anterior cingulate cortex (ACC) because this region is strongly linked to a positivity bias in older age.

We demonstrate an age-related reduction in updating beliefs when older adults are faced with undesirable, but not desirable, information about negative events. This greater ‘update bias’ in older age persisted even after controlling for a variety of variables including subjective rating scales and poorer overall memory. A structural brain correlate of this greater ‘update bias’ was evident in greater grey matter volume in the dorsal ACC in older but not in young adults.

We show a greater update bias in healthy older age. The link between this bias and relative volume of the ACC suggests a shared mechanism with an age-related positivity bias. Older adults frequently have to make important decisions relating to personal, health and financial issues. Our findings have wider behavioural implications in these contexts because an enhanced optimistic update bias may skew such real-world decision making.

Observing another person performing a complex action accelerates the observer's acquisition of the same action and limits the time-consuming process of learning by trial and error. Learning by observation requires specific skills such as attending, imitating and understanding contingencies. Individuals with autism spectrum disorder (ASD) exhibit deficits in these skills.

The performance of 20 ASD children was compared with that of a group of typically developing (TD) children matched for chronological age (CA), IQ and gender on tasks of learning of a visuomotor sequence by observation or by trial and error. Acquiring the correct sequence involved three phases: a detection phase (DP), in which participants discovered the correct sequence and learned how to perform the task; an exercise phase (EP), in which they reproduced the sequence until performance was error free; and an automatization phase (AP), in which by repeating the error-free sequence they became accurate and speedy.

In the DP, ASD children were impaired in detecting a sequence by trial and error only when the task was proposed as first, whereas they were as efficient as TD children in detecting a sequence by observation. In the EP, ASD children were as efficient as TD children. In the AP, ASD children were impaired in automatizing the sequence. Although the positive effect of learning by observation was evident, ASD children made a high number of imitative errors, indicating marked tendencies to hyperimitate.

These findings demonstrate the imitative abilities of ASD children although the presence of imitative errors indicates an impairment in the control of imitative behaviours.

Cross-sectional and longitudinal studies have shown a positive association between attention deficit hyperactivity disorder (ADHD) and problematic alcohol use in adults. To what extent this association is explained by genetic and environmental factors is largely unknown.

Data on ADHD and alcohol consumption were collected by self-report in 6024 adult Dutch twins. ADHD symptoms were assessed by three subscales of the Conners' Adult ADHD Rating Scales – Self-Report: Screening Version (CAARS–S:SV): inattentiveness, hyperactivity and the ADHD index (ADHD-I). Problem drinking was defined as at least two self-reported alcohol-related problems on the CAGE questionnaire. Structural equation modelling was applied to the bivariate twin data to estimate genetic and environmental influences.

Heritability of ADHD symptoms ranged between 32% and 40% and heritability of problem drinking was 50%. The positive correlation between ADHD symptoms and problem drinking was confirmed in this general population sample, with phenotypic correlations between 0.20 and 0.28 and genetic correlations between 0.39 and 0.50. Phenotypic correlations are primarily (61–100%) explained by genetic influences with non-shared environmental influences explaining the remaining covariance. No significant quantitative or qualitative gender differences in covariance structure were found.

This study convincingly shows that ADHD symptoms and problem drinking are moderately but significantly correlated in adults and that genetic correlations are primarily underlying this association. This suggests that early interventions are required to prevent adolescents with ADHD from developing problematic levels of alcohol use. Furthermore, clinicians who treat alcohol-dependent patients should be aware that the patient may have a co-morbid condition of ADHD; integrated interventions are required.

The results of twin and sibling studies suggest that executive functioning is a prime candidate endophenotype in attention deficit hyperactivity disorder (ADHD). However, studies have not assessed the co-segregation of executive function (EF) deficits from parents to offspring directly, and it is unclear whether executive functioning is an ADHD endophenotype in adolescents, given the substantial changes in prefrontal lobe functioning, EF and ADHD symptoms during adolescence.

We recruited 259 ADHD and 98 control families with an offspring average age of 17.3 years. All participants were assessed for ADHD and EF [inhibition, verbal (VWM) and visuospatial working memory (VsWM)]. Data were analysed using generalized estimating equations (GEEs).

Parental ADHD was associated with offspring ADHD and parental EF was associated with offspring EF but there were no cross-associations (parental ADHD was not associated with offspring EF or vice versa). Similar results were found when siblings were compared. EF deficits were only found in affected adolescents and not in their unaffected siblings or (un)affected parents.

The core EFs proposed to be aetiologically related to ADHD, that is working memory and inhibition, seem to be aetiologically independent of ADHD in adolescence. EF deficits documented in childhood in unaffected siblings were no longer present in adolescence, suggesting that children ‘grow out’ of early EF deficits. This is the first study to document ADHD and EF in a large family sample with adolescent offspring. The results suggest that, after childhood, the majority of influences on ADHD are independent from those on EF. This has potential implications for current aetiological models of causality in ADHD.

The common mental disorders (CMDs) of anxiety and depression are the most common form of poor mental health in the general population. Evidence from the small number of previous cohort studies on the role of neighbourhood factors in mental health is inconclusive. We tested the hypothesis that high levels of neighbourhood social cohesion modify an adverse association between change in individual mental health and neighbourhood deprivation.

We carried out a longitudinal multilevel analysis using data from the Caerphilly Health and Social Needs Cohort Study with a 7-year follow-up (n = 4426; age range 18–74 years at baseline). Neighbourhood deprivation and neighbourhood social cohesion were assessed at baseline and change in mental health between follow-up and baseline was assessed using the five-item Mental Health Inventory (MHI-5).

Residence in the most deprived neighbourhoods was negatively associated with change in mental health, after adjusting for baseline individual socio-economic risk factors and transitions in life events. This negative effect was significantly reduced in high social cohesion neighbourhoods. The predicted change in mental health score was calculated for the 10th and 90th centiles of the household low-income distribution. The difference between them was −2.8 in the low social cohesion group and 1.1 in the high cohesion group. The difference between the groups was 3.9 [95% confidence interval (CI) 0.2–7.6].

The public health burden of poor mental health and mental health inequality could potentially be reduced by strengthening social cohesion in deprived neighbourhoods. This offers a mechanism to address the adverse effect of neighbourhood deprivation on population mental health.

Central nervous system (CNS) dysfunction is a prominent feature of the functional gastrointestinal (GI) disorder, irritable bowel syndrome (IBS). However, the neurobiological and cognitive consequences of key pathophysiological features of IBS, such as stress-induced changes in hypothalamic–pituitary–adrenal (HPA)-axis functioning, is unknown. Our aim was to determine whether IBS is associated with cognitive impairment, independently of psychiatric co-morbidity, and whether cognitive performance is related to HPA-axis function.

A cross-sectional sample of 39 patients with IBS, a disease control group of 18 patients with Crohn's disease (CD) in clinical remission and 40 healthy age- and IQ-matched control participants were assessed using the Paired Associates Learning (PAL), Intra-Extra Dimensional Set Shift (IED) and Spatial Working Memory (SWM) tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) and a computerized Stroop test. HPA-axis function was determined by measuring the cortisol awakening response (CAR).

IBS patients exhibited a subtle visuospatial memory deficit at the PAL six- pattern stage (p = 0.03), which remained after psychiatric co-morbidity was controlled for (p = 0.04). Morning cortisol levels were lower in IBS (p = 0.04) and significantly associated with visuospatial memory performance within IBS only (p = 0.02).

For the first time, altered cognitive function on a hippocampal-mediated test of visuospatial memory, which was related to cortisol levels and independent of psychiatric co-morbidity, has been identified in IBS. Visuospatial memory impairment may be a common, but currently neglected, component of IBS. Further elucidation of the nature of this impairment may lead to a greater understanding of the underlying pathophysiology of IBS, and may provide novel therapeutic approaches.

Somatoform disorders are costly for society in terms of increased healthcare expenditure. Patients' illness perceptions have been found to play a role in somatoform disorders. However, it is unclear whether illness perceptions predict higher health costs in these patients.

A total of 1785 primary care patients presenting a new health complaint completed a questionnaire on their illness perceptions and emotional distress before the consultation. The physicians completed a questionnaire for each patient on diagnostics after the consultation. In a stratified subsample, physician interviewers established diagnoses of DSM-IV somatization and undifferentiated somatoform disorders (n = 144) using the Schedules for Clinical Assessment in Neuropsychiatry. Healthcare expenditure was obtained from Danish health registers for a 2-year follow-up period.

Patients had more negative perceptions of their well-defined physical health problems when they had a co-morbid somatoform disorder. A strong illness identity [β = 0.120, 95% confidence interval (CI) 0.029–0.212, p = 0.012], perceived negative consequences (β = 0.010, 95% CI 0.001–0.019, p = 0.024), a long timeline perspective (β = 0.013, 95% CI 0.005–0.021, p = 0.001), low personal control (β = − 0.009, 95% CI –0.015 to −0.002, p = 0.011) and negative emotional representations (β = 0.009, 95% CI 0.002–0.017, p = 0.020) predicted healthcare expenditure in somatoform disorders.

The results suggest that illness perceptions play a role in the perpetuation of symptoms in somatoform disorders and predict higher future healthcare expenditure among a subgroup of these patients.

Longitudinal symptoms of post-traumatic stress disorder (PTSD) are often characterized by heterogeneous trajectories, which may have unique pre-, peri- and post-trauma risk and protective factors. To date, however, no study has evaluated the nature and determinants of predominant trajectories of PTSD symptoms in World Trade Center (WTC) responders.

A total of 10835 WTC responders, including 4035 professional police responders and 6800 non-traditional responders (e.g. construction workers) who participated in the WTC Health Program (WTC-HP), were evaluated an average of 3, 6 and 8 years after the WTC attacks.

Among police responders, longitudinal PTSD symptoms were best characterized by four classes, with the majority (77.8%) in a resistant/resilient trajectory and the remainder exhibiting chronic (5.3%), recovering (8.4%) or delayed-onset (8.5%) symptom trajectories. Among non-traditional responders, a six-class solution was optimal, with fewer responders in a resistant/resilient trajectory (58.0%) and the remainder exhibiting recovering (12.3%), severe chronic (9.5%), subsyndromal increasing (7.3%), delayed-onset (6.7%) and moderate chronic (6.2%) trajectories. Prior psychiatric history, Hispanic ethnicity, severity of WTC exposure and WTC-related medical conditions were most strongly associated with symptomatic trajectories of PTSD symptoms in both groups of responders, whereas greater education and family and work support while working at the WTC site were protective against several of these trajectories.

Trajectories of PTSD symptoms in WTC responders are heterogeneous and associated uniquely with pre-, peri- and post-trauma risk and protective factors. Police responders were more likely than non-traditional responders to exhibit a resistant/resilient trajectory. These results underscore the importance of prevention, screening and treatment efforts that target high-risk disaster responders, particularly those with prior psychiatric history, high levels of trauma exposure and work-related medical morbidities.

Despite stress being considered a key factor in the pathophysiology of the functional gastrointestinal (GI) disorder irritable bowel syndrome (IBS), there is a paucity of information regarding the ability of IBS patients to respond to acute experimental stress. Insights into the stress response in IBS could open the way to novel therapeutic interventions. To this end, we assessed the response of a range of physiological and psychological parameters to the Trier Social Stress Test (TSST) in IBS.

Thirteen female patients with IBS and 15 healthy female age-matched control participants underwent a single exposure to the TSST. Salivary cortisol, salivary C-reactive protein (CRP), skin conductance level (SCL), GI symptoms, mood and self-reported stress were measured pre- and post-exposure to the TSST.

The hypothalamic–pituitary–adrenal (HPA) axis response to the TSST was sustained in IBS, as shown by a greater total cortisol output throughout (p = 0.035) and higher cortisol levels measured by an area under the curve with respect to ground (AUCG) analysis (p = 0.044). In IBS patients, GI symptoms increased significantly during the recovery period following exposure to the TSST (p = 0.045). Salivary CRP and SCL activity showed significant changes in relation to stress but with no differential effect between experimental groups.

Patients with IBS exhibit sustained HPA axis activity, and an increase in problematic GI symptoms in response to acute experimental psychosocial stress. These data pave the way for future interventional studies aimed at identifying novel therapeutic approaches to modulate the HPA axis and GI symptom response to acute psychosocial stress in IBS.