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Studying phenotypic and genetic characteristics of age at onset (AAO) and polarity at onset (PAO) in bipolar disorder can provide new insights into disease pathology and facilitate the development of screening tools.
To examine the genetic architecture of AAO and PAO and their association with bipolar disorder disease characteristics.
Genome-wide association studies (GWASs) and polygenic score (PGS) analyses of AAO (n = 12 977) and PAO (n = 6773) were conducted in patients with bipolar disorder from 34 cohorts and a replication sample (n = 2237). The association of onset with disease characteristics was investigated in two of these cohorts.
Earlier AAO was associated with a higher probability of psychotic symptoms, suicidality, lower educational attainment, not living together and fewer episodes. Depressive onset correlated with suicidality and manic onset correlated with delusions and manic episodes. Systematic differences in AAO between cohorts and continents of origin were observed. This was also reflected in single-nucleotide variant-based heritability estimates, with higher heritabilities for stricter onset definitions. Increased PGS for autism spectrum disorder (β = −0.34 years, s.e. = 0.08), major depression (β = −0.34 years, s.e. = 0.08), schizophrenia (β = −0.39 years, s.e. = 0.08), and educational attainment (β = −0.31 years, s.e. = 0.08) were associated with an earlier AAO. The AAO GWAS identified one significant locus, but this finding did not replicate. Neither GWAS nor PGS analyses yielded significant associations with PAO.
AAO and PAO are associated with indicators of bipolar disorder severity. Individuals with an earlier onset show an increased polygenic liability for a broad spectrum of psychiatric traits. Systematic differences in AAO across cohorts, continents and phenotype definitions introduce significant heterogeneity, affecting analyses.
Persistent negative symptoms are associated with worse outcome in both first-episode and chronic subjects with schizophrenia. The identification of these symptoms in recent-onset subjects is still controversial as retrospective data are often unavailable. The prospective assessment of persistence of negative symptoms might represent a valid alternative but the length of the persistence is still to be established. The present study investigated the prevalence of negative symptoms of moderate severity, unconfounded by depression and extrapyramidal symptoms at baseline in a large cohort of patients in the early stage of a schizophrenia-spectrum disorder, recruited to the OPTiMiSE trial. Persistent unconfounded negative symptoms were assessed at 4, 10 and 22 weeks of treatment. Symptomatic remission, attrition rate and psychosocial functioning was evaluated in subjects with short-term (4 weeks) persistent negative symptoms (PNS) and in those with negative symptoms that did not persist at follow-up and/or were confounded at baseline (N-PNS). Negative symptoms of moderate severity were observed in 59% of subjects at baseline and were associated to worse global functioning. PNS were observed in 7.9% of the cohort, unconfounded at both baseline and end of 4-week treatment. PNS subjects showed lower remission and higher attrition rates at the end of all treatment phases. Fifty-six percent of subjects completing phase 3 (clozapine treatment) had PNS, and 60% of them were non-remitters at the end of this phase. The presence of short-term PNS during the first phases of psychosis was associated with poor clinical outcome and resistance to antipsychotic treatment, including clozapine.
Prof Mucci has been a consultant and/or advisor to or has received honoraria from Gedeon Richter Bulgaria, Janssen Pharmaceuticals, Lundbeck, Otsuka, Pfizer and Pierre Fabre.
Genotype-first and within-family studies can elucidate factors that contribute to psychiatric illness. Combining these approaches, we investigated the patterns of influence of parental scores, a high-impact variant, and schizophrenia on dimensional neurobehavioral phenotypes implicated in major psychiatric disorders.
We quantitatively assessed cognitive (FSIQ, VIQ, PIQ), social, and motor functioning in 82 adult individuals with a de novo 22q11.2 deletion (22 with schizophrenia), and 148 of their unaffected parents. We calculated within-family correlations and effect sizes of the 22q11.2 deletion and schizophrenia, and used linear regressions to assess contributions to neurobehavioral measures.
Proband-parent intra-class correlations (ICC) were significant for cognitive measures (e.g. FSIQ ICC = 0.549, p < 0.0001), but not for social or motor measures. Compared to biparental scores, the 22q11.2 deletion conferred significant impairments for all phenotypes assessed (effect sizes −1.39 to −2.07 s.d.), strongest for PIQ. There were further decrements in those with schizophrenia. Regression models explained up to 37.7% of the variance in IQ and indicated that for proband IQ, parental IQ had larger effects than schizophrenia.
This study, for the first time, disentangles the impact of a high-impact variant from the modifying effects of parental scores and schizophrenia on relevant neurobehavioral phenotypes. The robust proband-parent correlations for cognitive measures, independent of the impact of the 22q11.2 deletion and of schizophrenia, suggest that, for certain phenotypes, shared genetic variation plays a significant role in expression. Molecular genetic and predictor studies are needed to elucidate shared factors and their contribution to psychiatric illness in this and other high-risk groups.
To evaluate safety, tolerability and overall effectiveness of a titrated- versus fixed-dose switching strategy from risperidone to aripiprazole in a general practice setting.
This 12-week, multicentre, open-label study included patients with schizophrenia (DSM-IV-TR) experiencing insufficient efficacy and/or safety/tolerability issues while receiving risperidone for ≥6 weeks. Patients were randomized to titrated- or fixed-dose switching regimens.
Discontinuations due to AEs were similar between titrated- and fixed-dose strategies (3.5% vs. 5.0%; p=0.448). Titrated- and fixed-dose groups showed improvements (Week 12) in mean PANSS Total scores (–14.8 vs. –17.2; LOCF), mean CGI-I scores (2.9 vs. 2.8; p=0.425; LOCF), ASEX scores (–1.5 vs. –1.9 from baseline; OC), serum prolactin levels (−48.7 vs. −48.5 from baseline; OC) and SWN scores (+8.6 vs. +10.3 from baseline; p=0.223; OC). POM scores indicated a preference for aripiprazole compared with risperidone using either regimen. Both strategies showed improvements (titrated-dose vs. fixed-dose; Week 12; LOCF) in social cognition as indicated by decreased GEOPTE patient (–5.3 vs. –6.1), caregiver (–5.4 vs. –9.9) and index scores (–5.1 vs. –9.8).
Switching to aripiprazole from risperidone can be effectively and safely achieved in a general practice setting through a slow down-titration of risperidone and either a titrated- or fixed-dose switching strategy for aripiprazole.
Data from two, identically designed, placebo-controlled, randomised, double-blind clinical trials (D1444C00132+D1444C00133) for once-daily extended-release quetiapine fumarate (QTP-XR) were pooled and analysed.
Evaluate dose response, efficacy and safety for QTP-XR in schizophrenia.
Post-hoc analysis of data from patients receiving QTP-XR 400, 600, 800 mg/day or placebo. Endpoints: least squares means (LSM) change from baseline to Day 42 in PANSS total and positive and negative subscale scores. No corrections for multiplicity were performed. Adverse events (AEs) were recorded.
914 patients were included; PANSS scores were assessed in the MITT population (n = 889). LSM change from baseline in PANSS total score diverged significantly from placebo at: Day 14 for QTP-XR 800 mg/day (-15.3 vs -12.1 for placebo; p = 0.018); Day 21 for 600 mg/day (-17.3 vs -14.2; p = 0.039); Day 42 for 400 mg/day (-19.2 vs -15.4; p = 0.033).
Jonckheere-Terpstra analysis of change in PANSS total score at Day 42 showed a significant QTP-XR dose response (p = 0.0196; p < 0.001 with placebo). PANSS positive scores diverged by Day 21 for both QTP-XR 800 (-5.7 vs -4.8; p = 0.049) and 600 mg/day (-5.8 vs -4.8; p = 0.046). PANSS negative scores diverged by Day 21 (-4.0 vs -3.2; p = 0.040) and 42 (-4.8 vs -3.6; p = 0.009) for QTP-XR 800 and 600 mg/day, respectively. AEs occurred in 59.4%, 66.5%, 62.1% and 56.2% of patients in the QTP-XR 800, 600, 400 mg/day and placebo groups, respectively. Most common AEs were somnolence, dry mouth, sedation, insomnia, dizziness, headache, constipation and nausea.
QTP-XR was generally well tolerated and demonstrated efficacy that increased with dose in schizophrenia.
Most studies aiming to predict transition to psychosis for individuals at ultra-high risk (UHR) have focused on either neurocognitive or clinical variables and have made little effort to combine the two. We aimed to investigate the relative value of neurocognitive and clinical variables for predicting transition to psychosis as well as long-term functional outcome.
Sixty-seven adolescents at UHR and 72 controls completed an extensive clinical and neurocognitive assessment. Forty-three UHR individuals and 47 controls participated in long-term follow-up approximately six years later. UHR adolescents who had converted to psychosis (UHR-P) were compared to individuals who had not (UHR-NP) and controls on clinical and neurocognitive variables. Regression analyses were performed to determine which baseline measures best predicted transition to psychosis and long-term functional outcome for UHR individuals.
Low IQ was the single neurocognitive parameter that discriminated UHR-P individuals from UHR-NP individuals and controls. The severity of attenuated positive symptoms was the only significant predictor of a transition to psychosis and disorganized symptoms were highly predictive of functional outcome.
IQ was lowest for those individuals at ultra high risk for psychosis who later went on to have a psychotic episode. However, IQ was not a good predictor of either transition or functional outcome. Rather, clinical measures proved to be the most important vulnerability markers for long-term outcome.
Smoking among adolescents is still a major public health problem and a global concern. Early onset and long-term smoking are associated with physical and psychological health problems.
To identify risk factors and comorbidities for occasional and daily smoking among European adolescents.
In the context of the Europe-wide 'Saving and Empowering Young Lives in Europe” (SEYLE) study we surveyed 12,328 youths at the age of 13 to 17 from 11 countries. We applied questions from the Global School-Based Student Health Survey to determine nicotine consumption as well as other risk behaviors. Psychiatric symptoms were assessed by the Strengths and Difficulties Questionnaire, the Becks Depression Inventory-II, the Zung Self-Rating Anxiety Scale,the Deliberate Self-Harm Inventory and the Paykel Suicide Scale.
On average 30.9% of adolescents reported daily smoking and the onset of smoking was reported by 35.3% between the age of 12 and 13 already. Multinomial logistic regression model showed significant correlations between adolescent smoking and migration background, living in single parent households, no physical activity, parental smoking and physical fights. Further it revealed significant associations of adolescent smoking with alcohol consumption, illegal drug use, anxiety, conduct problems, hyperactivity, suicidal ideation, self-injury and internet-dependence.
Our data show that adolescent smoking is associated with psychosocial factors, especially family setting and parental behaviors. Further, smoking and psychiatric problems are highly correlated. Therefore, early preventive measures are necessary and essential not only for adolescents but also for their parents.
The association between schizophrenia and decreased vitamin D levels is well documented. Low maternal and postnatal vitamin D levels suggest a possible etiological mechanism. Alternatively, vitamin D deficiency in patients with schizophrenia is presumably (also) the result of disease-related factors or demographic risk factors such as urbanicity.
In a study population of 347 patients with psychotic disorder and 282 controls, group differences in vitamin D concentration were examined. Within the patient group, associations between vitamin D, symptom levels and clinical variables were analyzed. Group × urbanicity interactions in the model of vitamin D concentration were examined. Both current urbanicity and urbanicity at birth were assessed.
Vitamin D concentrations were significantly lower in patients (B = −8.05; 95% confidence interval (CI) −13.68 to −2.42; p = 0.005). In patients, higher vitamin D concentration was associated with lower positive (B = −0.02; 95% CI −0.04 to 0.00; p = 0.049) and negative symptom levels (B = −0.03; 95% CI −0.05 to −0.01; p = 0.008). Group differences were moderated by urbanicity at birth (χ2 = 6.76 and p = 0.001), but not by current urbanicity (χ2 = 1.50 and p = 0.224). Urbanicity at birth was negatively associated with vitamin D concentration in patients (B = −5.11; 95% CI −9.41 to −0.81; p = 0.020), but not in controls (B = 0.72; 95% CI −4.02 to 5.46; p = 0.765).
Lower vitamin D levels in patients with psychotic disorder may in part reflect the effect of psychosis risk mediated by early environmental adversity. The data also suggest that lower vitamin D and psychopathology may be related through direct or indirect mechanisms.
Identifying factors that influence the functional outcome is an important goal in schizophrenia research. The 22q11.2 deletion syndrome (22q11DS) is a unique genetic model with high risk (20–25%) for schizophrenia. This study aimed to identify potentially targetable domains of neurocognitive functioning associated with functional outcome in adults with 22q11DS.
We used comprehensive neurocognitive test data available for 99 adults with 22q11DS (n = 43 with schizophrenia) and principal component analysis to derive four domains of neurocognition (Verbal Memory, Visual and Logical Memory, Motor Performance, and Executive Performance). We then investigated the association of these neurocognitive domains with adaptive functioning using Vineland Adaptive Behavior Scales data and a linear regression model that accounted for the effects of schizophrenia status and overall intellectual level.
The regression model explained 46.8% of the variance in functional outcome (p < 0.0001). Executive Performance was significantly associated with functional outcome (p = 0.048). Age and schizophrenia were also significant factors. The effects of Executive Performance on functioning did not significantly differ between those with and without psychotic illness.
The findings provide the impetus for further studies to examine the potential of directed (early) interventions targeting Executive Performance to improve long-term adaptive functional outcome in individuals with, or at high risk for, schizophrenia. Moreover, the neurocognitive test profiles may benefit caregivers and clinicians by providing insight into the relative strengths and weaknesses of individuals with 22q11DS, with and without psychotic illness.
A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related.
This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes.
The P300 amplitude and latency were not associated (regression coef. −0.06, 95% CI −0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10–0.28, p < 0.001). There was no evidence of associations between lateral ventricular volume and the other measures (all p > 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships.
The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.
Our understanding of the complex relationship between schizophrenia symptomatology and etiological factors can be improved by studying brain-based correlates of schizophrenia. Research showed that impairments in value processing and executive functioning, which have been associated with prefrontal brain areas [particularly the medial orbitofrontal cortex (MOFC)], are linked to negative symptoms. Here we tested the hypothesis that MOFC thickness is associated with negative symptom severity.
This study included 1985 individuals with schizophrenia from 17 research groups around the world contributing to the ENIGMA Schizophrenia Working Group. Cortical thickness values were obtained from T1-weighted structural brain scans using FreeSurfer. A meta-analysis across sites was conducted over effect sizes from a model predicting cortical thickness by negative symptom score (harmonized Scale for the Assessment of Negative Symptoms or Positive and Negative Syndrome Scale scores).
Meta-analytical results showed that left, but not right, MOFC thickness was significantly associated with negative symptom severity (βstd = −0.075; p = 0.019) after accounting for age, gender, and site. This effect remained significant (p = 0.036) in a model including overall illness severity. Covarying for duration of illness, age of onset, antipsychotic medication or handedness weakened the association of negative symptoms with left MOFC thickness. As part of a secondary analysis including 10 other prefrontal regions further associations in the left lateral orbitofrontal gyrus and pars opercularis emerged.
Using an unusually large cohort and a meta-analytical approach, our findings point towards a link between prefrontal thinning and negative symptom severity in schizophrenia. This finding provides further insight into the relationship between structural brain abnormalities and negative symptoms in schizophrenia.
Public health interest in norovirus (NoV) has increased in recent years following improved diagnostics, global burden estimates and the development of NoV vaccine candidates. This study aimed to describe the detection rate, clinical characteristics and environmental features associated with NoV detection in hospitalized children <5 years with diarrhoea in South Africa (SA). Between 2009 and 2013, prospective diarrhoeal surveillance was conducted at four sites in SA. Stool specimens were collected and screened for NoVs and other enteric pathogens using molecular and serological assays. Epidemiological and clinical data were compared in patients with or without detection of NoV. The study detected NoV in 15% (452/3103) of hospitalized children <5 years with diarrhoea with the majority of disease in children <2 years (92%; 417/452). NoV-positive children were more likely to present with diarrhoea and vomiting (odds ratio (OR) 1·3; 95% confidence interval (CI) 1·1–1·7; P = 0·011) with none-to-mild dehydration (adjusted OR 0·5; 95% CI 0·3–0·7) compared with NoV-negative children. Amongst children testing NoV positive, HIV-infected children were more likely to have prolonged hospitalization and increased mortality compared with HIV-uninfected children. Continued surveillance will be important to consider the epidemic trends and estimate the burden and risk of NoV infection in SA.
Malaria elimination is on global agendas following successful transmission reductions. Nevertheless moving from low to zero transmission is challenging. South Africa has an elimination target of 2018, which may or may not be realised in its hypoendemic areas.
The Agincourt Health and Demographic Surveillance System has monitored population health in north-eastern South Africa since 1992. Malaria deaths were analysed against individual factors, socioeconomic status, labour migration and weather over a 21-year period, eliciting trends over time and associations with covariates.
Of 13 251 registered deaths over 1.58 million person-years, 1.2% were attributed to malaria. Malaria mortality rates increased from 1992 to 2013, while mean daily maximum temperature rose by 1.5 °C. Travel to endemic Mozambique became easier, and malaria mortality increased in higher socioeconomic groups. Overall, malaria mortality was significantly associated with age, socioeconomic status, labour migration and employment, yearly rainfall and higher rainfall/temperature shortly before death.
Malaria persists as a small but important cause of death in this semi-rural South African population. Detailed longitudinal population data were crucial for these analyses. The findings highlight practical political, socioeconomic and environmental difficulties that may also be encountered elsewhere in moving from low-transmission scenarios to malaria elimination.
Many studies have shown associations between a history of childhood trauma and more severe or complex clinical features of bipolar disorders (BD), including suicide attempts and earlier illness onset. However, the psychopathological mechanisms underlying these associations are still unknown. Here, we investigated whether affective lability mediates the relationship between childhood trauma and the severe clinical features of BD.
A total of 342 participants with BD were recruited from France and Norway. Diagnosis and clinical characteristics were assessed using the Diagnostic Interview for Genetic Studies (DIGS) or the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I). Affective lability was measured using the short form of the Affective Lability Scale (ALS-SF). A history of childhood trauma was assessed using the Childhood Trauma Questionnaire (CTQ). Mediation analyses were performed using the SPSS process macro.
Using the mediation model and covariation for the lifetime number of major mood episodes, affective lability was found to statistically mediate the relationship between childhood trauma experiences and several clinical variables, including suicide attempts, mixed episodes and anxiety disorders. No significant mediation effects were found for rapid cycling or age at onset.
Our data suggest that affective lability may represent a psychological dimension that mediates the association between childhood traumatic experiences and the risk of a more severe or complex clinical expression of BD.
Poor educational achievement is associated with a range of psychiatric disorders. Several studies suggest that this underperformance is due to cognitive deficits that commence before disease onset and reflect a genetic risk for this disorder. However, the specificity and the familial contribution of this cognitive deficit are not clear. We analysed lifetime educational achievement of psychiatric patients diagnosed with schizophrenia, bipolar or depressive disorder and their unaffected siblings.
In a register-based case-control study, 1561 patients with schizophrenia, 813 patients with bipolar disorder, 8112 patients with depression, and their siblings were each matched with eight population controls. Patients, siblings and controls were compared on the highest educational stream they completed.
Lower educational achievement was present in schizophrenia patients from primary school onwards [completing primary school: odds ratio (OR) 0.69; completing secondary school: OR 0.69; completing academic education: OR 0.46], compared to patients with bipolar disorder or depression. Siblings of schizophrenia, bipolar or depressed patients showed no underachievement at primary or secondary school, but siblings of schizophrenia patients as well as siblings of depressed patients were less successful in their educational achievement after secondary school (completing academic education, schizophrenia siblings: OR 0.90; depressive disorder siblings: OR 0.91).
Educational underachievement from primary school onwards is specifically related to schizophrenia and not to bipolar disorder or depression. Moreover, it appears to be a harbinger of the illness, since it is not found in their siblings. These results add to evidence that early cognitive deficits are a distinct feature of the schizophrenia phenotype.
The purpose of this qualitative evaluation was to explore the experience of implementing routine telemonitoring (TM) in real-world primary care settings from the perspective of those delivering the intervention; namely the TM staff, and report on lessons learned that could inform future projects of this type.
Routine TM for high-risk patients within primary care practices may help improve chronic disease control and reduce complications, including unnecessary hospital admissions. However, little is known about how to integrate routine TM in busy primary care practices. A TM pilot for diabetic patients was attempted in six primary care practices as part of the Beacon Community in Western New York.
Semi-structured interviews were conducted with representatives of three TM agencies (n=8) participating in the pilot. Interviews were conducted over the phone or in person and lasted ~30 min. Interviews were audio-taped and transcribed. Analysis was conducted using immersion-crystallization to identify themes.
TM staff revealed several themes related to the experience of delivering TM in real-world primary care: (1) the nurse–patient relationship is central to a successful TM experience, (2) TM is a useful tool for understanding socio-economic context and its impact on patients’ health, (3) TM staff anecdotally report important potential impacts on patient health, and (4) integrating TM into primary care practices needs to be planned carefully.
This qualitative study identified challenges and unexpected benefits that might inform future efforts. Communication and integration between the TM agency and the practice, including the designation of a point person within the office to coordinate TM and help address the broader contextual needs of patients, are important considerations for future implementation. The role of the TM nurse in developing trust with patients and uncovering the social and economic context within which patients manage their diabetes was an unexpected benefit.
Africa is experiencing a rapid increase in adult obesity and associated cardiometabolic diseases (CMDs). The H3Africa AWI-Gen Collaborative Centre was established to examine genomic and environmental factors that influence body composition, body fat distribution and CMD risk, with the aim to provide insights towards effective treatment and intervention strategies. It provides a research platform of over 10 500 participants, 40–60 years old, from Burkina Faso, Ghana, Kenya and South Africa. Following a process that involved community engagement, training of project staff and participant informed consent, participants were administered detailed questionnaires, anthropometric measurements were taken and biospecimens collected. This generated a wealth of demographic, health history, environmental, behavioural and biomarker data. The H3Africa SNP array will be used for genome-wide association studies. AWI-Gen is building capacity to perform large epidemiological, genomic and epigenomic studies across several African counties and strives to become a valuable resource for research collaborations in Africa.
The contribution of subsidized food commodities to total food consumption is unknown. We estimated the proportion of individual energy intake from food commodities receiving the largest subsidies from 1995 to 2010 (corn, soyabeans, wheat, rice, sorghum, dairy and livestock).
Integrating information from three federal databases (MyPyramid Equivalents, Food Intakes Converted to Retail Commodities, and What We Eat in America) with data from the 2001–2006 National Health and Nutrition Examination Surveys, we computed a Subsidy Score representing the percentage of total energy intake from subsidized commodities. We examined the score’s distribution and the probability of having a ‘high’ (≥70th percentile) v. ‘low’ (≤30th percentile) score, across the population and subgroups, using multivariate logistic regression.
Community-dwelling adults in the USA.
Participants (n 11 811) aged 18–64 years.
Median Subsidy Score was 56·7 % (interquartile range 47·2–65·4 %). Younger, less educated, poorer, and Mexican Americans had higher scores. After controlling for covariates, age, education and income remained independently associated with the score: compared with individuals aged 55–64 years, individuals aged 18–24 years had a 50 % higher probability of having a high score (P<0·0001). Individuals reporting less than high-school education had 21 % higher probability of having a high score than individuals reporting college completion or higher (P=0·003); individuals in the lowest tertile of income had an 11 % higher probability of having a high score compared with individuals in the highest tertile (P=0·02).
Over 50 % of energy in US diets is derived from federally subsidized commodities.
Smaller hippocampal volume has often been observed in patients with post-traumatic stress disorder (PTSD). However, there is no consensus whether this is a result of stress/trauma exposure, or constitutes a vulnerability factor for the development of PTSD. Second, it is unclear whether hippocampal volume normalizes with successful treatment of PTSD, or whether a smaller hippocampus is a risk factor for the persistence of PTSD.
Magnetic resonance imaging (MRI) scans and clinical interviews were collected from 47 war veterans with PTSD, 25 healthy war veterans (combat controls) and 25 healthy non-military controls. All veterans were scanned a second time with a 6- to 8-month interval, during which PTSD patients received trauma-focused therapy. Based on post-treatment PTSD symptoms, patients were divided into a PTSD group who was in remission (n = 22) and a group in whom PTSD symptoms persisted (n = 22). MRI data were analysed with Freesurfer.
Smaller left hippocampal volume was observed in PTSD patients compared with both control groups. Hippocampal volume of the combat controls did not differ from healthy controls. Second, pre- and post-treatment analyses of the PTSD patients and combat controls revealed reduced (left) hippocampal volume only in the persistent patients at both time points. Importantly, hippocampal volume did not change with treatment.
Our findings suggest that a smaller (left) hippocampus is not the result of stress/trauma exposure. Furthermore, hippocampal volume does not increase with successful treatment. Instead, we demonstrate for the first time that a smaller (left) hippocampus constitutes a risk factor for the persistence of PTSD.