Mental health is a tricky branch of medicine – psychiatrists deal with significant diagnostic and research challenges, and some patients struggle with the stigma they may face socially due to having a mental disorder. In a bid to educate the public about psychiatric conditions, Mental Health Awareness Week, which this year runs from 13th–19th May, is focusing on raising awareness about how exercise can positively affect mental health. In fact, there is increasing focus on modifying key lifestyle factors as primary prevention strategies for mental health disorders, and in a recent opinion article published in BMC Medicine, Felice Jacka and colleagues argue that depression and anxiety should be ranked amongst prevalent medical conditions affected by poor diet and physical inactivity. In another opinion article, Almudena Sanchez-Villegas and Miguel Martínez-Gonzalez discuss how diet may help prevent depression, and recommend that observational studies and clinical trials need to be carried out to confirm the association.

Psychiatry is also very topical this week due to the imminent release of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) by the American Psychiatric Association. This has been undergoing revision for some time, and although greatly anticipated, has also led to much debate, with some arguing that the DSM-5 should not be heralded as the ultimate guide in diagnosing psychiatric disorders. To focus on the many controversies in this area of medicine, a new article collection, Current Controversies in Psychiatry, has been published in BMC Medicine to address the current challenges in psychiatry from diagnosis to co-morbidities.

As Michael Berk discusses in an editorial to launch our article collection, the debate on diagnostic categories in mental health based on DSM-5 is disproportionate to what the changes will actually mean. He highlights that while the modifications in diagnostic criteria are useful, the limitations should also be kept in perspective amongst clinicians and regulators, and warns that adhering too tightly to imperfect criteria will hamper progress in research.

In a debate article, Ian Hickie and colleagues argue that the diagnostic criteria can be improved by developing new approaches that identify pathways underlying the illnesses rather than using broad categories to describe psychiatric disorders. However, in another debate article, Victoria Cosgrove and Trisha Suppes highlight that boundaries between the diagnosis of bipolar disorder I, schizophrenia and schizoaffective disorder are preserved in the DSM-5 criteria, as there is not yet enough data to justify a continuous model of psychosis.

It should be noted that the DSM diagnoses are based on consensus guided by clinical symptoms, and are not derived from any quantifiable research measures. Another closely related diagnostic guideline is the tenth edition of the International Classification of Diseases (ICD-10) developed by the WHO, which is also undergoing revision (the ICD-11 is due for release in 2015); some argue that the two sets of guidelines, although developed for use by different branches of health professionals, suffer from similar limitations.

In an attempt to produce a more informative set of diagnostic guidelines, the National Institute of Mental Health (NIMH) launched the Research Domain Criteria (RDoC) project in 2009, which aims to incorporate genetics, neuroimaging and cognitive science to develop a new classification system. In a debate article, Bruce Cuthbert and Thomas Insel argue that future psychiatric nosologies will be informed by the RDoC, which will help achieve precision medicine for mental disorders. Thomas Insel expands on this project further in his NIMH blog. The move towards focusing on a more personalized approach to psychiatric research is also highlighted in a review article by Charles Nemeroff and colleagues, where the genetics, epigenetics, biomarkers, treatment response and environmental factors of mood disorders and schizophrenia are discussed, with particular emphasis on the impact of neuroimaging on personalized medicine in psychiatry.

The patient’s perspective in all this should also not be forgotten, and as Dan Stein and Katherine Phillips point out, the fifth DSM revision incorporated public feedback for the first time. Stein and Phillips both worked as part of the subgroup for the obsessive compulsive and related disorders criteria, and in a commentary describe the importance of taking patient opinion into account.

One thing that cannot be underestimated is the impact psychiatric conditions have on overall health. In particular, depression has been associated with obesity and cardiovascular diseases (CVD), and in a review article Brenda Penninx and colleagues examine the biological pathways and the dysregulation between depressive symptoms and somatic health. Additionally, Peter de Jonge and colleagues argue that although there is a link between coronary heart disease (CHD) and depression, this association is confounded by heterogeneity, such that depression is a non-causal risk factor for CHD. However, Kenneth Freedland and Robert Carney dispute that depression predicts CHD but admit that better methods are required to ascertain whether depression is a causal risk factor for CHD, which could help determine treatment strategies for CVD prevention.

Further articles will be added to this series to focus on some of the controversies and open questions in psychiatry, so keep an eye out for developments in our article collection. In the meantime, we wish you good mental health!