This issue contains a commentary on the paper by Degenhardt et al. and one review on participant distress in psychiatric research. Other sets of papers examine various aspects of cannabis and other substance use disorders, borderline and other personality disorders, and six individual papers examine a variety of topics.

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. 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. The aim was to examine the temporal relationships over 10 months between cannabis use and symptoms of psychosis and depression in people with schizophrenia and related disorders. The design was a prospective study of 101 patients with schizophrenia and related disorders who were assessed monthly over 10 months on medication compliance, cannabis and other drug use, symptoms of depression and symptoms of psychosis.

Method. Linear regression methods to assess relationships between cannabis use and symptoms of psychosis and depression while adjusting for serial dependence, medication compliance and other demographic and clinical variables.

Results. Cannabis use predicted a small but statistically significant increase in symptoms of psychosis, but not depression, after controlling for other differences between cannabis users and non-users. Symptoms of depression and psychosis did not predict cannabis use.

Conclusion. Continued cannabis use by persons with schizophrenia predicts a small increase in psychotic symptom severity but not vice versa.

Background. A self-medication hypothesis has been proposed to explain the association between cannabis use and psychiatric and behavioral problems. However, little is known about the reasons for use and reactions while intoxicated in cannabis users who suffer from depression or problems controlling violent behavior.

Method. We assessed 119 cannabis-dependent subjects using the Schedules of Clinical Assessment in Neuropsychiatry (SCAN), parts of the Addiction Severity Index (ASI), and questionnaires on reasons for cannabis use and reactions to cannabis use while intoxicated. Participants with lifetime depression and problems controlling violent behavior were compared to subjects without such problems. Validity of the groupings was corroborated by use of a psychiatric treatment register, previous use of psychotropic medication and convictions for violence.

Results. Subjects with lifetime depression used cannabis for the same reasons as others. While under the influence of cannabis, they more often experienced depression, sadness, anxiety and paranoia, and they were less likely to report happiness or euphoria. Participants reporting problems controlling violent behavior more often used cannabis to decrease aggression, decrease suspiciousness, and for relaxation; while intoxicated they more often reacted with aggression.

Conclusions. Subjects with prior depression do not use cannabis as a mean of self-medication. They are more likely to experience specific increases of adverse symptoms while under the influence of cannabis, and are less likely to experience specific symptom relief. There is some evidence that cannabis is used as a means of self-medication for problems controlling aggression.

Background. Although an obvious environmental factor influencing drug use, the sources of individual differences in drug availability (DA) are unknown.

Method. This report is based on 1788 adult males from the Mid-Atlantic Twin Registry who participated in a structured telephone interview that included retrospective assessments of DA (cigarette, alcohol, marijuana, cocaine and stimulants) between ages 8 and 25. We fitted a biometric dual change score (DCS) model, adapted for ordinal data, to model latent growth and estimate the genetic and environmental components of variance over time.

Results. DA, despite being considered an environmental risk factor, is under both genetic and environmental control. For cigarette, alcohol, marijuana and cocaine availability, there was an overall increase in additive genetic variance and a decline in shared environmental variance over time. Non-shared environmental variance remained steady. Stimulant availability did not follow this pattern. Instead, there was an upswing in shared environmental effects with increasing age.

Conclusion. We have modeled the genetic and environmental architecture of changes in DA across adolescence. The rise in additive genetic variance over time coincides with acceleration in the expression of individual differences, probably brought on by an increase in personal freedom and a reduction in social constraints. Understanding the etiology of DA is likely to reveal key components, acting directly or indirectly, in the pathway(s) leading to drug initiation, abuse and dependence.

Background. Although affective instability is an essential criterion for borderline personality disorder (BPD), it has rarely been reported as an outcome criterion. To date, most of the studies assessing state affective instability in BPD using paper-pencil diaries did not find indications of this characteristic, whereas in others studies, the findings were conflicting. Furthermore, the pattern of instability that characterizes BPD has not yet been identified.

Method. We assessed the affective states of 50 female patients with BPD and 50 female healthy controls (HC) during 24 hours of their everyday life using electronic diaries.

Results. In contrast to previous paper-and-pencil diary studies, heightened affective instability for both emotional valence and distress was clearly exhibited in the BPD group but not in the HC group. Inconsistencies in previous papers can be explained by the methods used to calculate instability (see Appendix). In additional, we were able to identify a group-specific pattern of instability in the BPD group characterized by sudden large decreases from positive mood states. Furthermore, 48% of the declines from a very positive mood state in BPD were so large that they reached a negative mood state. This was the case in only 9% of the HC group, suggesting that BPD patients, on average, take less time to fluctuate from a very positive mood state to a negative mood state.

Conclusion. Future ambulatory monitoring studies will be useful in clarifying which events lead to the reported, sudden decrease in positive mood in BPD patients.

Background. Current biological concepts of borderline personality disorder (BPD) emphasize the interference of emotional hyperarousal and cognitive functions. A prototypical example is episodic memory. Pre-clinical investigations of emotion–episodic memory interactions have shown specific retrograde and anterograde episodic memory changes in response to emotional stimuli. These changes are amygdala dependent and vary as a function of emotional arousal and valence.

Method. To determine whether there is amygdala hyper-responsiveness to emotional stimuli as the underlying pathological substrate of cognitive dysfunction in BPD, 16 unmedicated female patients with BPD were tested on the behavioural indices of emotion-induced amnesia and hypermnesia established in 16 healthy controls.

Results. BPD patients displayed enhanced retrograde and anterograde amnesia in response to presentation of negative stimuli, while positive stimuli elicited no episodic memory-modulating effects.

Conclusion. These findings suggest that an amygdala hyper-responsiveness to negative stimuli may serve as a crucial aetiological contributor to emotion-induced cognitive dysfunction in BPD.

Background. The categorical classification system for personality disorder (PD) has been frequently criticized and several alternative dimensional models have been proposed.

Method. Antecedent, concurrent and predictive markers of construct validity were examined for three models of PDs: the Five-Factor Model (FFM), the Schedule for Nonadaptive and Adaptive Personality (SNAP) model and the DSM-IV in the Collaborative Study of Personality Disorders (CLPS) sample.

Results. All models showed substantial validity across a variety of marker variables over time. Dimensional models (including dimensionalized DSM-IV) consistently outperformed the conventional categorical diagnosis in predicting external variables, such as subsequent suicidal gestures and hospitalizations. FFM facets failed to improve upon the validity of higher-order factors upon cross-validation. Data demonstrated the importance of both stable trait and dynamic psychopathological influences in predicting external criteria over time.

Conclusions. The results support a dimensional representation of PDs that assesses both stable traits and dynamic processes.

Background. Although communication disturbances (CD) have been associated with poor cognitive control, it is unclear whether they are associated specifically with poor cognitive control or with poor cognition in general. The current research examined whether (a) two specific components of cognitive control, working memory and interference resolution, were associated with CD, and (b) associations between CD and cognitive control could be accounted for by generalized poor cognitive performance.

Method. In this study, as healthy volunteers spoke, the level of cognitive demands was experimentally increased, thereby simulating cognitive deficits (i.e. a reduction in the degree to which certain types of cognitive processes could be used for speech). Hence, this research examined whether simulated cognitive deficits would cause an increase in CD. Participants also completed separate cognitive tasks that assessed working memory, interference resolution and general cognitive ability.

Results. An increase in working memory demands caused an increase in CD. Moreover, working memory demands interacted with interference resolution demands, with the greatest amount of CD caused by both high working memory and high interference resolution demands. By contrast, increasing another cognitive demand, sustained attention, did not increase CD. Furthermore, performance on separate working memory and interference resolution tasks interacted to predict CD on the experimental speech task. However, performance on a psychometrically matched cognitive task did not predict CD.

Conclusion. Overall, the current study provides evidence that working memory and interference resolution may be specifically associated with CD and that manipulations of these cognitive control processes can cause an increase in CD.

Background. Well-being is an important determinant of health and social outcomes. Measures of positive mental health states are needed for population-based research. The 12-item General Health Questionnaire (GHQ-12) has been widely used in many settings and languages, and includes positively and negatively worded items. Our aim was to test the hypothesis that the GHQ-12 assesses both positive and negative mental health and that these domains are independent of one another.

Method. Exploratory (EFA) and confirmatory (CFA) factor analyses were conducted using data from the British Household Panel Survey (BHPS) and the Health Survey for England (HSE). Regression models were used to assess whether associations with individual and household characteristics varied across positive and negative mental health dimensions. We also explored higher-level variance in these measures, between electoral wards.

Results. We found a consistent, replicable factor structure in both datasets. EFA results indicated a two-factor solution, and CFA demonstrated that this was superior to a one-factor model. These factors correspond to ‘symptoms of mental disorder’ and ‘positive mental health’. Further analyses demonstrated independence of these factors in associations with age, gender, employment status, poor housing and household composition. Statistically significant ward-level variance was found for symptoms of mental disorder but not positive mental health.

Conclusions. The GHQ-12 measures both positive and negative aspects of mental health, and although correlated, these dimensions have some independence. The GHQ-12 could be used to measure positive mental health in population-based research.

Background. Brain reserve is a property of the central nervous system related to complex mental activity which may mediate the course and clinical expression of brain injury. Since there is no instrument that comprehensively assesses complex mental activity through the lifespan, we developed and tested the Lifetime of Experiences Questionnaire (LEQ) in a prospective study of healthy ageing.

Method. The LEQ assesses educational, occupational and cognitive lifestyle activities at different stages through life. Test–retest, item analysis and Item Response Theory (IRT) were used to determine reliability. Dimensionality was evaluated using factor analysis. Validity was established through IRT analysis of test performance, correlation with an extant contemporaneous instrument (Cognitive Activities Scale; CAS) and prediction of global cognitive change over 18 months controlling for age, baseline cognition and hypertension.

Results. In a sample of healthy older individuals (n=79) the LEQ was found to be consistent, coherent and discriminate between individuals with high and low mental activity levels. Factor analysis revealed a dominant factor which loaded heavily on education, occupation and leisure activity. Total LEQ was significantly correlated with the CAS. Furthermore, individuals with higher LEQ scores showed less cognitive decline over 18 months, independent of covariates (r=0·37, p=0·003).

Conclusions. The LEQ is a reliable and valid instrument for assessing complex lifespan mental activity which is protective against cognitive decline. The LEQ is therefore proposed as a useful tool for estimating brain reserve in older individuals and further development is anticipated.

Background. The extended recession and stagnant housing market in the 1990s following the boom of the late 1980s resulted in more than half a million housing repossessions. This study explores the impact of unsustainable housing commitments on psychological well-being. We test the hypotheses that housing payment problems and housing arrears have adverse impacts on heads of households' psychological well-being over and above those caused by financial hardship more generally.

Method. Data came from the British Household Panel Survey 1991–2003 and the samples for analysis consist of: (1) 5651 male head of households producing 26618 person-year observations, and (2) 2534 female head of households producing 9091 person-year observations. Summary statistics and multivariate, fixed effects regression models are used. Mental health was measured by the 12-item General Health Questionnaire.

Results. For male heads of households housing payment problems and entering arrears have significant detrimental effects on mental well-being and for female heads of households longer-term housing payment problems and arrears have significant detrimental effects on mental well-being. The sizes of these effects are in addition to and larger in magnitude than those associated with financial hardship more generally. The net effects appear to be relatively stable over the time of the panel data.

Conclusions. This study provides evidence that housing payment problems have independent psychological costs over and above those associated with general financial hardship. The magnitude of the effect is similar to that shown for marital breakdown and job loss.

Background. Reduction of health inequalities is a major policy goal in the UK. While there is general recognition of the disadvantaged position of people with mental health problems, the extent of inequality, particularly the association with socio-economic characteristics, has not been widely studied. We aimed to measure income-related inequality in the distribution of psychiatric disorders and to compare with inequality in other health domains.

Method. The concentration index (CI) approach was used to examine income-related inequality in mental health using data from the Psychiatric Morbidity Survey 2000 for Britain.

Results. There is marked inequality unfavourable to lower income groups with respect to mental health disorders. The extent of inequality increases with the severity of problems, with the greatest inequality observed for psychosis. Income-related inequality for psychiatric disorders is higher than for general health in the UK. Standardized CIs suggest that these inequalities are not due to the demographic composition of the income quintiles.

Conclusions. Income-related inequalities exist in mental health in Britain. As much of the observed inequality is probably due to factors associated with income and not due to the demographic composition of the income quintiles, it may be that these inequalities are potentially ‘avoidable’.

Background. There is a lack of current detailed national data on the prevalence, correlates, disability and co-morbidity of DSM-IV specific phobia (SP), the prevalence of specific objects and situations feared, and associations between impairment, treatment and co-morbidity and the number of specific situations and objects feared, among adults in the USA.

Method. The data were derived from a large (43093) representative sample of the adult population in the USA.

Results. Prevalences of 12-month and lifetime DSM-IV SP were 7·1% and 9·4% respectively. Being female, young, and low income increased risk, while being Asian or Hispanic decreased risk (p<0·05). The mean age at onset of SP was 9·7 years, the mean duration of episode was 20·1 years and only 8·0% reported treatment specifically for SP. Most specific phobias involved multiple fears, and an increasing number of fears, regardless of content, was associated with greater disability and impairment, treatment seeking and co-morbidity with other Axis I and II disorders.

Conclusions. SP is a highly prevalent, disabling and co-morbid disorder in the US adult population. The early onset of SP and the disorders most strongly associated with it highlights the need for longitudinal studies beginning in early childhood. Results suggest the existence of a generalized subtype of SP much like social phobia, which, once revealed, may lead to a classification of SP that is more etiologically and therapeutically meaningful.