Increasing attention has been given by researchers to cannabis use in individuals with psychosis. As psychoses are relatively low-prevalence disorders, research has been mostly been restricted to small-scale studies of treatment samples. The reported prevalence estimates obtained from these studies vary widely.

To provide prevalence estimates based on larger samples and to examine sources of variability in prevalence estimates across studies.

Data from 53 studies of treatment samples and 5 epidemiological studies were analysed.

Based on treatment sample data, prevalence estimates were calculated for current use (23.0%), current misuse (11.3%), 12-month use (29.2%), 12-month misuse (18.8%), lifetime use (42.1%) and lifetime misuse (22.5%). Epidemiological studies consistently reported higher cannabis use and misuse prevalence in people with psychosis.

The factor most consistently associated with increased odds of cannabis prevalence was specificity of diagnosis. Factors such as consumption patterns and study design merit further consideration.

Obsessions and compulsions may occur in the post-streptococcal disorders Sydenham's chorea and paediatric autoimmune neuropsychiatric disorders associated with streptococcus (PANDAS). The proposed mediators are anti-basal ganglia antibodies (ABGA)

We tested the hypothesis that post-streptococcal autoimmunity may have a role in ‘idiopathic’ obsessive–compulsive disorder (OCD)

We examined 50 children with OCD for ABGA using enzyme-linked immunosorbent assay (ELISA) and western immunoblotting. The findings were compared with paediatric autoimmune (n=50), neurological (n=100) and streptococcal (n=40) controls.

The mean ABGA binding on ELISA was elevated in the patient cohort compared with all control groups (P<0.005 in all comparisons). Western immunoblotting revealed positive antibody binding (as seen in Sydenham's chorea) in 42% of the patient cohort compared with 2–10% of control groups (P<0.001 in all comparisons)

Our findings support the hypothesis that central nervous system autoimmunity may have a role in a significant subgroup of cases of OCD. Further study is required to examine whether the antibodies concerned are pathogenic.

Studies have shown increased bilateral activation in the prefrontal cortex when normal individuals lie, but there have been no structural imaging studies of deceitful individuals.

To assess whether deceitful individuals show structural abnormalities in prefrontal grey and white matter volume.

Prefrontal grey and white matter volumes were assessed using structural magnetic resonance imaging in 12 individuals who pathologically lie, cheat and deceive (‘liars’), 16 antisocial controls and 21 normal controls.

Liars showed a 22–26% increase in prefrontal white matter and a 36–42% reduction in prefrontal grey/white ratios compared with both antisocial controls and normal controls.

These findings provide the first evidence of a structural brain deficit in liars, they implicate the prefrontal cortex as an important (but not sole) component in the neural circuitry underlying lying and provide an initial neurobiological correlate of a deceitful personality.

Abnormal illness behaviour by proxy (also known as factitious illness by proxy or Munchhausen syndrome by proxy) is a type of child maltreatment, the origins of which are poorly understood.

To describe attachment representations in a cohort of mothers demonstrating abnormal illness behaviour by proxy.

Sixty-seven mothers who had shown this behaviour took part in a semi-structured interview assessing their attachment representations.

Only 12 mothers (18%) were rated secure in terms of their own childhood attachments. There was evidence of unresolved trauma or loss reactions in 40 mothers (60%). Eighteen mothers (27%) gave unusually disorganised and incoherent accounts of attachment relationships in their own childhoods. The frequency of these attachment categories is higher than in normal non-clinical samples.

Insecure attachment is a risk factor for this type of child maltreatment. Therapeutic interventions could be offered in relation to unresolved traumatic stress or bereavement responses. Further study of similar groups, such as mothers with sick children or mothers with histories of traumatic experience, would be a useful next step.

For decades there has been interest in the possibility that people with schizophrenia might have some protection against cancer, and that, if this were so, it might hold clues about aetiological mechanisms in schizophrenia.

To study cancer incidence in schizophrenia.

Cohort analysis of linked hospital and death records was used to compare cancer rates in people with schizophrenia with a reference cohort.

We did not find a reduced risk for cancer overall (rate ratio 0.99, 95% CI 0.90–1.08) or for most individual cancers. There was, however, a significantly low rate ratio for skin cancer (0.56, 95% CI 0.36–0.83)

We found no evidence that schizophrenia confers protection against cancer in general. Low rates of skin cancer are consistent with the hypothesis that sun exposure may influence the development of schizophrenia, although other explanations are also possible.

Much of China lacks well-developed services for people with schizophrenia and their families, and most of the existing services focus on hospitals. There is a need for culturally sensitive family treatments offered by nurses.

To conduct a longitudinal experimental study examining the effect of patient and family education in a sample of Chinese people with schizophrenia.

A randomised controlled trial was conducted in a large hospital with a sample of 101 patients with schizophrenia and their families. Data were collected at admission and at discharge, and then at 3 and 9 months after discharge. The intervention group received family education, and data on their knowledge about schizophrenia, symptoms, functioning, psychosocial behaviour, relapse and medication adherence were collected and compared with the control group.

There was a significant improvement in knowledge about schizophrenia in the experimental group and a significant difference in symptom scores and functioning at 9 months after discharge. Patients who were non-adherent to medication regimens were more likely to relapse.

Family education on schizophrenia by nurses in China was effective in improving knowledge and promoting improvement in patients' symptoms.

People with schizophrenia make poor dietary choices.

To measure the impact of giving free fruit and vegetables for 6 months on eating habits in schizophrenia.

We randomly allocated 102 people with schizophrenia in two areas of Scotland to receive free fruit and vegetables for 6 months, supported by instruction in meal planning and food preparation; free fruit and vegetables alone; or to continue as before. Diet was assessed using the Scottish Health Survey questionnaire. Blood samples to measure micronutrients were taken and mental state, body mass index, level of physical activity and future risk of coronary heart disease (CHD) were assessed.

After the intervention, those who received free fruit and vegetables, or free fruit and vegetables and associated instruction, were consuming significantly more fruit and vegetables than those in the treatment as usual group. Consumption fell to pre-intervention levels 12 months after the intervention stopped. There was no between-group difference at any time in blood micronutrients, body mass index, physical activity or risk of CHD.

The diet of people with schizophrenia improved when they were given free fruit and vegetables but this was not sustained after withdrawal of the intervention. A support programme added no benefit.

Venlafaxine extended-release (ER) has proven efficacy in the treatment of anxiety symptoms in major depression, generalised anxiety disorder and social anxiety disorder.

To evaluate the efficacy, safety and tolerability of venlafaxine ER in treating panic disorder.

Adult out-patients (n=361) with panic disorder were randomly assigned to receive venlafaxine ER (75–225 mg/day) or placebo for up to 10 weeks in a double-blind study.

Venlafaxine ER was not associated with a greater proportion of patients free from full-symptom panic attacks at the finalon-therapy evaluation, but was associated with lower mean panic attack frequency and a higher proportion free from limited-symptom panic attacks, higher response and remission rates, and improvements in anticipatory anxiety, fear and avoidance. Adverse events were comparable with those of the drug in depression and anxiety disorders.

Venlafaxine ER seems to be effective and well tolerated in the short-term treatment of panic disorder.

The outcome for opiate-dependent patients seeking abstinence is unclear in this era of improved access to methadone maintenance.

To measure the outcome 2–3 years after in-patient treatment.

Opiate-dependent patients admitted with a goal of abstinence were followed-up. A structured interview examined drug use and treatment in the preceding month.

Five patients had died and 109 (76%) of the remaining 144 were interviewed. Fifty per cent (54 patients) reported recent opiate misuse and 57% (62) were on methadone maintenance. Twenty-three per cent (25 patients) were abstinent (i.e. neither using opiates nor on methadone maintenance). Abstinence was significantly associated with completion of the 6-week in-patient treatment programme and attendance at out-patient after-care, and negatively associated with a family history of substance misuse.

Abstinence remains an attainable goal. As the principal influence on outcome was treatment adherence, inpatient services should seek to enhance rates of programme completion. Aftercare should be provided to patients. We caution against use of pre-treatment patient characteristics as criteria for prioritising access to in-patient treatment.

Despite the widespread use of the Brief Psychiatric Rating Scale (BPRS), the clinical meaning of its total score and cut-off values used to define treatment response are unclear.

To link the BPRS to Clinical Global Impression (CGI) ratings.

Equipercentile linking of BPRS and CGI ratings from seven drug trials in acutely ill patients with schizophrenia (n=1979).

‘Mildly ill’ according to the CGI approximately corresponded to a BPRS total score of 31, ‘moderately ill’ to a BPRS score of 41 and ‘markedly ill’ to a BPRS score of 53. ‘Minimally improved’ according to the CGI score was associated with percentage BPRS reductions of 24, 27 and 30% at weeks 1, 2 and 4, respectively. The corresponding numbers for a CGI rating of ‘much improved’ were 44, 53 and 58%

The results provide a clearer understanding of how to interpret BPRS total and percentage reduction scores in clinical trials with patients acutely ill with schizophrenia who are experiencing positive symptoms.

Previous work on the reliability of mental capacity assessments in patients with psychiatric illness has been limited.

To describe the interrater reliability of two independent assessments of capacity to consent to treatment, as well as assessments made by a panel of clinicians based on the same interview.

Fifty-five patients were interviewed by two interviewers 1–7 days apart and a binary (yes/no) capacity judgement was made, guided by the MacArthur Competence Assessment Tool for Treatment (MacCAT-T). Four senior clinicians used transcripts of the interviews to judge capacity.

There was excellent agreement between the two interviewers for capacity judgements made at separate interviews (kappa=0.82). A high level of agreement was seen between senior clinicians for capacity judgements of the same interview (mean kappa=0.84)

In combination with a clinical interview, the MacCAT–T can be used to produce highly reliable judgements of capacity.

Little is known about the proportion of psychiatric in-patients who lack capacity to make treatment decisions, or the associations of lack of capacity.

To determine the prevalence of psychiatric in-patients who lack capacity to make decisions about current treatment and to identify demographic and clinical associations with lack of mental capacity.

Patients (n=112) were interviewed soon after admission to hospital and a binary judgement of capacity was made, guided by the MacArthur Competence Tool for Treatment. Demographic and clinical information was collected from an interview and case notes.

Of the 112 participants, 49 (43.8%) lacked treatment-related decisional capacity Mania and psychosis, poor insight, delusions and Black and minority ethnic group were associated with mental incapacity. Of the 49 patients lacking capacity, 30 (61%) were detained under the Mental Health Act 1983. Of the 63 with capacity, 6 (9.5%) were detained.

Lack of treatment-related decisional capacity is a common but by no means inevitable correlate of admission to a psychiatric in-patient unit.