Anxiety disorders are common, often have a chronic course and frequently coexist with other psychiatric disorders. Psychological therapy is recommended as first-line treatment, but equitable access remains a challenge. This month's Cochrane Corner review assesses the evidence for the efficacy of therapist-supported cognitive-behavioural therapy (CBT) for anxiety disorders delivered via the internet. Although internet delivery of therapy is attractive for many reasons, and the results of this preliminary review suggest that it is efficacious, this is a rapidly expanding field. Further updates of this review will include more evidence to support or refute the use of this new method of treatment delivery, either alongside or in preference to standard face-to-face CBT.

This commentary questions a Cochrane review that examined whether first-rank symptoms are a useful diagnostic tool for differentiating schizophrenia from other psychotic disorders. It concludes that first-rank symptoms are not particularly accurate in this role, although they might be useful initial screening questions in community surveys or waiting-room screening.

Drug treatments are commonly used for sleep disturbance in Alzheimer's disease, although none have a specific licence for this indication. This month's Cochrane review assessed the available evidence of benefit or harm in the use of these medications. The review identified two studies of melatonin, which did not show significant improvement in sleep over placebo. One study of trazodone suggested a beneficial effect on sleep, but its small sample size limits the generalisability of the results. Larger studies are needed, with careful assessment of the evidence for possible improvements in sleep but also of important side-effects such as falls and increased confusion.

The Mini-Mental State Examination (MMSE) is the most widely used bedside cognitive test. It has previously been shown to be poor as a case-finding tool for both dementia and mild cognitive impairment (MCI). This month's Cochrane Corner review examines whether the MMSE might be used as a risk prediction tool for later dementia in those with established MCI. From 11 studies of modest quality, it appears that the MMSE alone should not be relied on to predict later deterioration in people with MCI. As this is the case, it is likely that only a combination of predictors would be able to accurately predict progression from MCI to dementia.

Maintenance drug treatment in bipolar disorder is a key component of management. There is clinical uncertainty about the relative efficacy of valproate, either alone or in combination, particularly in comparison to lithium. This month's Cochrane corner review aimed to summarise the best evidence available. This commentary puts the findings into their clinical context and updates them in the light of subsequent analyses and the recent revision of the NICE guidelines on bipolar disorder.

Individuals with severe mental illness have increased rates of physical health problems and reduced life expectancy. As a vulnerable population, they have been identified as needing increased physical health monitoring and treatment. The first of two Cochrane reviews considered here assessed the evidence for the benefit of monitoring but found no studies that could be included. The second reviewed the evidence for provision of general physical healthcare advice. Although the results were suggestive of benefit, the evidence, where available, was of poor quality. These reviews highlight an important area for future research to evaluate the relative health and cost benefits of different types of intervention.

It is well established that the immune system can modulate brain functioning and influence behavioural processes. Awareness of communication between the immune and nervous systems has, over the years, progressively heightened interest in the relationship between psychiatric disorders and immune function. By reviewing findings from studies investigating inflammation in the periphery and in the central nervous systems, we summarise here the evidence linking inflammation to the development of depression, schizophrenia and bipolar disorder. We discuss how a pathophysiological role for inflammation has now been recognised across different psychiatric disorders, at least in a significant subpopulation of patients. Finally, we discuss a possible role for these findings in the development of future diagnostic classifications of psychiatric disorders as well as of new treatment strategies.