Few studies have assessed psychopathic traits in community samples of young people. We investigated the predictive utility of callous and unemotional traits in a representative sample of 5770 young people from Great Britain. Teachers provided information on the presence of callous and unemotional traits and parents completed the Strengths and Difficulties Questionnaire to determine the level and impact of psychiatric problems at baseline, 12 and 24 months later. Baseline callous and unemotional trait scores independently predicted the number and intensity of conduct, emotional and hyperactivity symptoms at follow-up. Callous and unemotional traits are longitudinally associated with the level and impact of childhood psychiatric problems.

Cannabis contains various cannabinoids, two of which have almost opposing actions: δ9-tetrahydrocannabinol (Δ9-THC) is psychotomimetic, whereas cannabidiol (CBD) has antipsychotic effects. Hair samples were analysed to examine levels of Δ9-THC and CBD in 140 individuals. Three clear groups emerged: ‘THC only’, ‘THC+CBD’ and those with no cannabinoid in hair. The THC only group showed higher levels of positive schizophrenia-like symptoms compared with the no cannabinoid and THC+CBD groups, and higher levels of delusions compared with the no cannabinoid group. This provides evidence of the divergent properties of cannabinoids and has important implications for research into the link between cannabis use and psychosis.

Although the hippocampus has been found to be smaller in people with depression, the clinical relevance of this is unclear. We investigated hippocampal volume (using high-resolution magnetic resonance imaging) and 2-year outcome in 57 patients with major depression. The left and right hippocampal volumes of patients with a depression relapse were significantly smaller than those of healthy controls. Our results support the hypothesis that the hippocampus is crucial in the outcome of depression.

The relationship between DSM-IV anxiety disorders and their clinical characteristics in mothers and anxiety in offspring was examined in 933 mother–child pairs from a longitudinal community study. Offspring of mothers with an anxiety disorder had an elevated risk of developing any anxiety disorder, compared with offspring of mothers with no anxiety disorder. Increased risk of anxiety in the offspring was especially associated with maternal social phobia and generalised anxiety disorder, and with maternal diagnoses of early onset, greater number and more severe impairment. These results suggest that the type of maternal anxiety disorder and its severity of manifestation contribute to mother-offspring aggregation of anxiety.

Facial affect discrimination and identification were assessed in 86 clinical high-risk individuals and compared with 50 individuals with first-episode psychosis, 53 with multiepisode schizophrenia and 55 non-psychiatric controls. On the identification task the non-psychiatric controls performed significantly better than all other groups, and on discrimination significantly better than both patient groups. Deficits in facial affect recognition appear to be present before the onset of psychosis and may be a vulnerability marker.

We examined nationally representative data from the 2002–2004 South Africa Stress and Health Study, a national household probability sample of 4351 persons aged 18 years and older: 9.1% of respondents reported lifetime suicide ideation, 3.8% a plan and 2.9% an attempt. Among four ethnic groups, the Coloureda group had the highest lifetime prevalence for attempts (7.1%). Those at higher risk of suicide attempts had one or more DSM-IV disorders.

It is commonly – but wrongly – assumed that there are no important differences between the clinical presentations of major depressive disorder and bipolar depression. Here we compare clinical course variables and depressive symptom profiles in a large sample of individuals with major depressive disorder (n=593) and bipolar disorder (n=443). Clinical characteristics associated with a bipolar course included the presence of psychosis, diurnal mood variation and hypersomnia during depressive episodes, and a greater number of shorter depressive episodes. Such features should alert a clinician to a possible bipolar course. This is important because optimal management is not the same for bipolar and unipolar depression.

The relative incidence of childhood-onset bipolar illness in the USA compared with that in Europe is controversial. We examined this issue in more than 500 out-patients (average age 42 years) with bipolar illness who reported age at onset of first episode, family history, and childhood physical or sexual abuse. Childhood or adolescent onset of bipolar illness was reported by 61% of those in the US cohort but by only 30% of those in The Netherlands or Germany. In the USA there was also twice the incidence of childhood adversity and genetic/familial risk for affective disorder. The findings deserve replication and further exploration.

The incidence of depression is higher in women than men but the reverse pattern is seen with suicide. In a cohort of 50 692 Norwegians we found that suicide risk associated with comorbid anxiety and depression was two-fold higher in men (OR=7.4, 95% CI 3.1-17.5) than women (OR=2.9, 95% CI 0.8-10.6), although statistical evidence for a difference was weak (P=0.4). If real, these gender differences could reflect either a more severe symptom profile in men with self-reported anxiety and depression, perhaps because of gender differences with regard to the stigma associated with mental illness, or gender differences in the way men respond to mental illness (e.g. self-medication/help-seeking).

This paper investigates how childhood socio-economic position influences the risk for midlife depressive and anxiety disorders at 45 years of age, assessed by the Clinical Interview Schedule in 9377 participants of the 1958 British Birth Cohort. Socio-economic position was measured by Registrar General Social Class in childhood and adulthood. The association of paternal manual socio-economic position with any diagnosis at 45 years of age was accounted for after adjustment for adult socio-economic position. Manual socio-economic position in women at 42 years of age was associated with midlife depressive disorder and any diagnosis; these associations were diminished by adjustment for childhood psychological disorders. Effects of childhood socio-economic position on adult depressive disorders may be mediated through adult socio-economic position.

Traditional healers' practices are widespread around the world, yet their diagnostic skills have rarely been investigated. This exploratory study examines whether yachactaitas (Quichua healers) in the Andes identify cases of psychiatric illness in their communities. For over 18 months, ten yachactaitas participated in the identification of 50 individuals with the condition known as llaqui. Medical and psychiatric evaluation indicated that most of those so diagnosed had a DSM–III–R mental disorder. None of the participants with llaqui was considered healthy in biomedical or psychiatric terms. It is suggested that yachactaitas might indeed identify general psychiatric cases in their communities, and that this might be useful for screening purposes.