Diatheses confer vulnerability to disorder but are not necessarily manifest overtly or consistently. It is suggested that the main empirical findings of studies with abnormal personality support the notion that they are diatheses rather than disorders. This includes their onset early in life, their variability of expression dependent on setting, their greater association with more severe disorders and their acceptance as intrinsic components of functioning by most suffering from these conditions. It is argued that a separate axis of classification for personality diatheses rather than disorders is justified.

Background. Hopelessness is considered a pre-eminent risk factor for suicide and non-fatal self-harm. We aimed to quantify the ability of the Beck Hopelessness Scale (BHS) to predict these two outcomes.

Method. Medline, Embase, PsycINFO and Cinahl were searched to January 2006. We included cohort studies in which the BHS was applied and patients were followed-up to establish subsequent suicide or non-fatal self-harm. Four studies provided usable data on suicide, and six studies provided data on non-fatal self-harm. Summary sensitivity, specificity, likelihood ratios and diagnostic odds ratios (DORs) were calculated for each study. Random effects meta-analytic pooling across studies at the standard cut-off point ([ges ]9) was undertaken and summary receiver operating characteristic (ROC) curves constructed.

Results. For suicide, pooled sensitivity was 0·80 [95% confidence interval (CI) 0·68–0·90], pooled specificity was 0·42 (95% CI 0·41–0·44), and the pooled DOR was 3·39 (95% CI 1·29–8·88). For non-fatal self-harm, pooled sensitivity was 0·78 (95% CI 0·74–0·82), pooled specificity was 0·42 (95% CI 0·38–0·45), and the pooled DOR was 2·27 (95% CI 1·53–3·37).

Conclusion. The standard cut-off point on the BHS identifies a high-risk group for potential suicide, but the magnitude of the risk is lower than previously reported estimates. The standard cut-off point is also capable of identifying those who are at risk of future self-harm, but the low specificity rate means it is unlikely to be of use in targeting treatment designed to lower the rate of repetition.

Background. Cost evaluation research in the mental health field is being increasingly recognized as a way to achieve a more effective deployment of scarce resources. However, there is a paucity of studies that seek to identify predictors of psychiatric service utilization and costs. This paper aims to critically review the published research in the field of psychiatric service utilization and costs, and discusses current methodological developments in this field.

Method. Sixteen studies were identified and are critically reviewed.

Results. No single variable alone can explain variations in costs between patients; instead, a range of different clinical and non-clinical variables provides a greater explanation of cost variations. Having a history of previous psychiatric service use is the most consistent predictor of higher psychiatric costs. Only one study considers indirect costs incurred by users, their families and friends and society as a whole, with the remaining 15 studies focusing on direct mental health care costs. There is a lack of studies that consider the future psychiatric service utilization and costs of care of children and older people. The cross-validation of predictive models is not yet routine, with only four of the studies including a cross-validation procedure.

Conclusions. The predictive approach in mental health cost evaluation has relevance for both mental health policy and practice. However, there is a paucity of studies that focus on children, older people and indirect costs. Furthermore, there remain a number of methodological challenges to address.

A high proportion of people who have a serious mental illness also use non-prescribed psychoactive drugs. This association is perhaps most apparent, and possibly also has the greatest implications for health, in relation to tobacco use. In fact recognition of the special relationship between mental illness and smoking was recently reflected in exemption of psychiatric units from legislation to ban smoking in enclosed public spaces in the UK (UK Smoking Law Resource Centre, 2007). The prevalence of tobacco use has generally decreased in most European, North American and Australasian countries, however, use of other psychoactive drugs, has not followed this pattern (Advisory Council on the Misuse of Drugs, 2006). Cannabis use in particular is widespread, both in the general population but especially so amongst people with serious and enduring mental illness, particularly psychotic illness. Recognition of the particular coincidence of cannabis use with psychotic illness amongst psychiatric patients was one of the observations that precipitated current debate around the possible aetiological role of cannabis use in relation to incidence of schizophrenia (Thornicroft, 1990; Hall, 2006; Macleod et al. 2006).

Background. Traditional models of psychiatric epidemiology often assume that the relationship between individuals and their environment is unidirectional, from environment to person. Accumulating evidence from developmental and genetic studies has made this perspective increasingly untenable.

Method. Literature search using Medline, PsycINFO, article references and contact with experts to identify all papers examining the heritability of measures of environments of relevance to psychiatry/psychology.

Results. We identified 55 independent studies organized into seven categories: general and specific stressful life events (SLEs), parenting as reported by child, parenting reported by parent, family environment, social support, peer interactions, and marital quality. Thirty-five environmental measures in these categories were examined by at least two studies and produced weighted heritability estimates ranging from 7% to 39%, with most falling between 15% and 35%. The weighted heritability for all environmental measures in all studies was 27%. The weighted heritability for environmental measures by rating method was: self-report 29%, informant report 26%, and direct rater or videotape observation (typically examining 10 min of behavior) 14%.

Conclusion. Genetic influences on measures of the environment are pervasive in extent and modest to moderate in impact. These findings largely reflect ‘actual behavior’ rather than ‘only perceptions’. Etiologic models for psychiatric illness need to account for the non-trivial influences of genetic factors on environmental experiences.

Background. We studied to what extent internet-based cognitive behaviour therapy (CBT) programs for symptoms of depression and anxiety are effective.

Method. A meta-analysis of 12 randomized controlled trials.

Results. The effects of internet-based CBT were compared to control conditions in 13 contrast groups with a total number of 2334 participants. A meta-analysis on treatment contrasts resulted in a moderate to large mean effect size [fixed effects analysis (FEA) d=0·40, mixed effects analysis (MEA) d=0·60] and significant heterogeneity. Therefore, two sets of post hoc subgroup analyses were carried out. Analyses on the type of symptoms revealed that interventions for symptoms of depression had a small mean effect size (FEA d=0·27, MEA d=0·32) and significant heterogeneity. Further analyses showed that one study could be regarded as an outlier. Analyses without this study showed a small mean effect size and moderate, non-significant heterogeneity. Interventions for anxiety had a large mean effect size (FEA and MEA d=0·96) and very low heterogeneity. When examining the second set of subgroups, based on therapist assistance, no significant heterogeneity was found. Interventions with therapist support (n=5) had a large mean effect size, while interventions without therapist support (n=6) had a small mean effect size (FEA d=0·24, MEA d=0·26).

Conclusions. In general, effect sizes of internet-based interventions for symptoms of anxiety were larger than effect sizes for depressive symptoms; however, this might be explained by differences in the amount of therapist support.

Nearly a century of observational studies and more recent longitudinal surveys reveal that, in infancy, girls and boys use force at similar rates. Over the next few years boys become significantly more aggressive. Alternative hypotheses accounting for the widening gender gap are evaluated. These include hypotheses about normative patterns of male escalation and female desistance; boys' preference for active play that promotes aggression; girls' tendency to hide aggression; girls' use of alternative forms of aggression; boys' increased risk for the cognitive and emotional problems that are linked to aggression; boys' sensitivity to situational triggers of aggression; and boys' vulnerability to adverse rearing environments. The evidence bearing on each hypothesis is mixed. In general, the overall difference between the sexes appears to be produced by a minority of boys who deploy aggression at high rates. Three general principles govern the emergence of sex differences in aggression: female precocity, male vulnerability, and the salience of sex as a social category that shapes children's lives.

Background. Gender differences are commonly reported in schizophrenia research, especially with regard to age at onset. Few studies have reported the age- and gender-specific incidence of schizophrenia in people aged up to 71 years, and no studies have reported the cumulative incidence of schizophrenia in people aged up to 71 years.

Method. Two cohorts were established by linking data from the Danish Civil Registration System (DCRS) with data from the Danish Psychiatric Central Register (DPCR), which covers all incident cases of schizophrenia from 15 to 71 years. We estimated the gender- and age-specific incidence rates of schizophrenia for people aged up to 71 years. We also estimated the cumulative incidences.

Results. The incidence rates for males significantly exceeded those for females in the age range from 17 to 40 years. By their 72nd birthday, 1·59% of males and 1·17% of females had developed schizophrenia.

Conclusion. Male sex is a major risk factor for the development of schizophrenia.

Background. This review tackles the question: ‘Is bereavement related depression (BRD) the same or different from standard (non-bereavement-related) major depression (SMD)?’ To answer this question, we examined published data on key characteristics that define and characterize SMD to assess whether they also characterize BRD.

Method. We searched all English-language reports in Medline up to November 2006 to identify relevant studies. Bibliographies of located articles were searched for additional studies.

Results. Consistent with the position that BRD is distinct from SMD, some, but not all, studies report that men are as likely as women to have BRD and that past or family histories of SMD do not predict BRD. With greater consistency, studies suggest that, like SMD, BRD is: more common in younger than in older adults, predicated by poor health or low social support, followed by recurrent episodes of major depressive episode (MDE), and associated with impaired immunological responses, altered sleep architecture, and responsivity to antidepressant treatment.

Conclusions. Overall, the prevailing evidence more strongly supports similarities than differences between BRD and SMD. Because so few studies focus on BRD occurring within the first 2 months of bereavement, the period identified by the DSM to exclude the diagnosis of MDE, more research is needed specifically on this group to help us evaluate the validity of this important diagnostic convention.

Background. Childhood factors have been associated with increased risk of developing post-traumatic stress disorder (PTSD). Previous studies assessed only a limited number of childhood factors retrospectively. We examined the association between childhood neurodevelopmental, temperamental, behavioral and family environmental characteristics assessed before age 11 years and the development of PTSD up to age 32 years in a birth cohort.

Method. Members of a 1972–73 New Zealand birth cohort (n=1037) who were assessed at ages 26 and 32 years for PTSD as defined by DSM-IV.

Results. We identified two sets of childhood risk factors. The first set of risk factors was associated both with increased risk of trauma exposure and with PTSD assessed at age 26. These included childhood externalizing characteristics and family environmental stressors, specifically maternal distress and loss of a parent. The second set of risk factors affected risk for PTSD only and included low IQ and chronic environmental adversity. The effect of cumulative childhood factors on risk of PTSD at age 26 was substantial; over 58% of cohort members in the highest risk quartile for three developmental factors had PTSD as compared to only 25% of those not at high risk on any factors. Low IQ at age 5, antisocial behavior, and poverty before age 11 continued to predict PTSD related to traumatic events that occurred between the ages of 26 and 32.

Conclusions. Developmental capacities and conditions of early childhood may increase both risk of trauma exposure and the risk that individuals will respond adversely to traumatic exposures. Rather than being solely a response to trauma, PTSD may have developmental origins.

Background. Both psychopathic personality traits and antisocial behavior are influenced by genetic as well as environmental factors. However, little is known about how genetic and environmental factors contribute to the associations between the psychopathic personality traits and antisocial behavior.

Method. Data were drawn from a longitudinal population-based twin sample including all 1480 twin pairs born in Sweden between May 1985 and December 1986. The twins responded to mailed self-report questionnaires at two occasions: 1999 (twins 13–14 years old), and 2002 (twins 16–17 years old).

Results. A common genetic factor loaded substantially on both psychopathic personality traits and antisocial behavior, whereas a common shared environmental factor loaded exclusively on antisocial behavior.

Conclusions. The genetic overlap between psychopathic personality traits and antisocial behavior may reflect a genetic vulnerability to externalizing psychopathology. The finding of shared environmental influences only in antisocial behavior suggests an etiological distinction between psychopathic personality dimensions and antisocial behavior. Knowledge about temperamental correlates to antisocial behavior is important for identification of susceptibility genes, as well as for possible prevention through identification of at-risk children early in life.

Background. There has been ethical concern that participants in psychiatric research will become distressed and their mental state might worsen.

Method. A systematic search was carried out for studies that examined distress following participation in research that involved the assessment of psychiatric state or associated risk factors. There were 46 relevant studies.

Results. A minority of participants become distressed immediately after participation, with distress more likely in studies of traumatic experiences. There is limited evidence on longer-term effects, but what there is suggests no adverse impact. Positive reactions to participation show little association with distress and these are more common than negative reactions. Very few studies of distress in research have used control groups to establish causal associations. However, what evidence there is suggests no causal role, including for research on suicidality. Researchers in this area have made a range of suggestions about ethical practice.

Conclusions. A minority of participants in psychiatric research become distressed, but there is no evidence of longer-term harm. Nevertheless, researchers need to take account of ethical concerns in designing studies. Future research in the area needs to be carried out with stronger designs involving control groups.

Background. Non-professional treatment programmes are presumed to relieve the extensive need for care of anxiety and depression disorders. This study investigates the effectiveness of cognitive self- therapy (CST) in the treatment of depression or generalized anxiety disorder.

Method. Patients (n=151) were randomized to receive CST or treatment as usual (TAU) in a trial lasting for 18 months, measuring symptoms (SCL-90; main outcome), social functions, quality of life and utilization of care.

Results. Patients in both conditions improved significantly, but no difference was found between the conditions. Reduction of symptoms, improvement of social functions and medical utilization were maintained at the end of the 18 months. Medical care utilization (therapist contact and hospitalization) was lower for CST than for TAU. No suicides occurred.

Conclusions. Cognitive self-therapy is likely to decrease the need for care of chronic depression and anxiety disorders, but it has not been proven to be more effective than treatment as usual.

Background. Urban birth, a risk factor for schizophrenia, is more frequent among second-generation immigrants. The aim of the current study was to determine whether the increased risk for schizophrenia found in second-generation immigrants is explained by the degree of urbanization of birthplace and/or factors related to parentage, such as geographic origin or history of residence abroad during upbringing.

Method. Using data from the Danish Civil Registration System (CRS), we established a population-based cohort of 2·0 million Danes (persons born in Denmark). Schizophrenia in cohort members was identified by cross-linkage with the Danish Psychiatric Central Register.

Results. The relative risk of developing schizophrenia was 1·93 [95% confidence interval (CI) 1·79–2·08] and 2·96 (95% CI 2·49–3·51) among persons with one or both parents foreign-born respectively compared to native Danes. Adjustment for urbanization of birthplace and parental characteristics reduced these risks slightly. However, urbanization had a lesser effect in second-generation immigrants than in Danes. History of residence abroad was a risk factor for schizophrenia, regardless of whether parents were foreign-born or native Danes.

Conclusion. The increased risk found in second-generation immigrants cannot be explained by urbanization or parental characteristics pertaining to age, mental illness, geographic origin or residence abroad during a child's upbringing.