Dementia is a progressive and irreversible deterioration in cognition that has a significant impact on the person’s activities of daily living and quality of life. Currently, there is no curative treatment for dementia, and the treatments used in clinical practice have limited therapeutic reach. We begin this descriptive review with a discussion of apolipoprotein E4 (apoE4) and its role in the pathogenesis of dementia. We consider the molecular involvement of statins and why they are no longer clinically indicated in mild cognitive impairment or mild to moderate dementia. We then explore the evidence regarding the effects of statins and cyclodextrins on apoE4, presenting evidence in support of and against their neuroprotective effects in cognitive impairment. Although the studies on cyclodextrins have all been on animals, they provide a strong background for a potential research hypothesis for future clinical trials in the treatment of dementia.

This editorial introduces the first of two special issues of BJPsych Advances devoted to liaison psychiatry, reflecting collaborative healthcare for patients presenting with both physical and mental health conditions, whether in acute general hospitals, out-patient clinics, in-patient wards or accident and emergency departments.

Music therapy attempts to facilitate communication and expression – core problems for autistic people – through the development of experiences and relationships mediated by music. This commentary assesses a Cochrane Review of the effects of music therapy, compared with placebo or standard care, for autistic people, and its conclusion that music therapy is probably associated with an increased chance of global improvement and perhaps a slight increase in quality of life and reduction in total autism symptom severity in the short to medium term. The review was not able to examine longer-term effects as the longest follow-up period was 12 months. The certainty of the evidence was graded from moderate to very low, and therefore the results need to be viewed with caution.

In the past 20 years, there has been growing interest in post-traumatic stress disorder (PTSD) in people with intellectual disabilities. It is now widely recognised that individuals with intellectual disabilities are more likely to be affected by traumatic experiences than those without. The authors discuss advancements in understanding trauma and PTSD in individuals with intellectual disabilities, as well as improvements in clinical assessment and treatment. They also emphasise the need for further research into the effects of trauma and PTSD on this vulnerable and often marginalised population.

The perinatal period is an important time for infant and parent. Vulnerable parents with pre-existing challenges, such as adverse experiences in their own childhood, might find the transition to parenthood particularly hard. The Cochrane Review considered here sought to assess the effectiveness of parenting interventions provided to parents with symptoms of complex post-traumatic stress disorder and/or a history of childhood maltreatment, with the aim of improving the parents’ well-being or parenting capacity. In this commentary we focus on how the limited evidence base, along with some key aspects of the review’s methodology, might have influenced its finding that such interventions showed little or no benefit.

This critical appraisal of a Cochrane Review assesses the efficacy of ketamine for treating unipolar major depressive disorder. The review included 31 randomised controlled trials involving ketamine. Results indicate that intravenous (i.v.) ketamine significantly improves antidepressant response compared with i.v. saline and, to a lesser extent, i.v. midazolam within 24–72 h. However, the evidence is constrained by performance bias owing to masking (‘blinding’) concerns and study heterogeneity, necessitating further robust research to confirm ketamine's clinical potential.

Overweight and obesity are growing health concerns globally. Technological advances drive interest in smartphone applications as possible health behaviour interventions to promote lifestyle change in these conditions. This article critically appraises a Cochrane Review of 18 studies (2703 participants) of smartphone app interventions for overweight or obesity in adolescents and adults and considers its relevance to clinical practice and research. The review's results suggest that there may be minimal benefit to the use of smartphone apps, but the evidence is very uncertain, lacking high-quality, replicable studies.

Metabolic dysfunction is an established phenomenon in people with severe mental illness (SMI), and it has a higher prevalence than in the general population. It is associated with increased morbidity and mortality, and effective recognition and management are essential to enable good psychiatric care. Despite widespread awareness of this disparity for several decades, health outcomes continue to worsen, highlighting the need for more effective preventive and treatment measures. This article outlines the risk factors that contribute to metabolic dysfunction in this population, including genetic, environmental and pharmacological factors, and considers underlying metabolic pathophysiological processes as part of SMI itself. To aid discussions with patients, recognition and interpretation of metabolic risk factors are outlined, together with mitigating strategies. Novel areas of uncertainty are discussed, including the use of a ketogenic diet. This article advocates use of the term ‘metabolic psychiatry’, to increase awareness of the significant overlap between psychiatric illness and metabolic dysfunction.

Sleep disturbances are common in dementia and are associated with numerous problems. Medication is not clearly effective and is potentially problematic, giving a clear role for non-pharmacological measures. The Cochrane Review discussed here suggested that physical and social activities and carer interventions potentially improve sleep in dementia, although the evidence was not conclusive. The review was limited by the heterogeneity present and the low quality of evidence. The authors’ choice of primary outcomes leads to a wider discussion on the clinical relevance of available outcomes in evaluating sleep in dementia and the potential role for patients and carers in informing this.