Attention to deficits of mixed mood states: Hype or activity?

Those of you interested in such matters will no doubt have noticed modest but important changes in the internal architecture of the Journal. Despite the outcome of the Cricket World Cup, the ties between Australia and New Zealand are stronger than ever – at least in psychiatry – as reflected by the appointment of Professor Richard Porter as Deputy Editor for Australian & New Zealand Journal of Psychiatry (ANZJP) and the reappointment of Professor Roger Mulder as an Associate Editor – finally returned from the wilds of administrative responsibility. Both are wonderful Kiwis ¹ and both will no doubt further enliven the Anglo – Indian – Scottish – South African – Australian mix in our ‘batting order’ making the ANZJP even more varied and interesting.

Fielding papers bowled to the Journal is very much like playing cricket: a misjudged googly can easily lead to losing a wicket, but at the same time playing it safe and avoiding difficult deliveries is just not cricket. Despite the challenges, the editors of ANZJP remain focused on key topics of clinical and research importance. The Journal refuses to shy away from contention and controversy and continues to navigate difficult clinical issues by way of encouraging thought-provoking debates.

This issue of ANZJP is no exception and features robust discussion on the reliability and validity of attention deficit hyperactivity disorder (ADHD) and the definition and implications of mixed mood states as defined by Diagnostic and Statistical Manual of Mental Disorders–Fifth Edition (DSM-5). These diagnoses are difficult and problematic. The putative intersection between depression and mania (major depression and bipolar disorder) is of particular interest because it may hold the key to understanding the neurobiology of mood disorders and possibly the development of novel and more effective treatments. Clinically, this is important because diagnosis inevitably leads to treatment, but in practice this varies considerably. Primarily, this is a consequence of mixed mood states being poorly characterised in both clinical and research settings. Several definitions of mixed moods have been proposed, but a reliable and clinically meaningful definition is yet to emerge. Mixed mood states are not unique in this regard and a similar problem plagues ADHD, with many challenging the usefulness of current DSM diagnostic criteria, while others defend them vehemently. Again this debate is important because, in reality, diagnosis almost always precipitates some form of treatment.

In psychiatry, such discussions are vital and necessary for building a solid platform for research from which understanding can be translated into clinical practice. Facilitating this process are advances in technology and scientific endeavour that continue to shed light on brain biology as wonderfully exemplified by the Key Review article in this issue by Brain Power and Jeffrey Looi, on the role of the thalamus and how it serves as the lens through which the brain perceives (Power and Looi, this issue). With ease and purpose, the authors provide coruscating insights into the neurobiology of the thalamus and its possible role in neurodegenerative disorders. Crammed with illuminating figures and an informative narrative that melds history with cutting-edge neuroscience, their erudite article is truly enlightening in every sense of the word.

A similarly exciting, but distinctly shorter, article is this month’s Editor’s Choice. This article (Guo et al., this issue) interrogates medication-naïve individuals with major depression using the latest neuroimaging techniques, Wenbin Guo and colleagues identify dramatic fronto-limbic network activity and homogeneity changes that appear to be independent of clinical variables. The novel findings from this study point to a possible neural marker for major depression – and perhaps suggest a potential first step to further understanding this illness and developing new therapies.

Thinking along these lines, Steven Marwaha and colleagues (this issue) propose that mood instability is a precursor to depressive illness and that interventions targeting sleep difficulties alongside mood instability may diminish the risk of future depressive episodes. This requires characterising mood with greater granularity and better understanding its nature. In this vein, Maria Reinares and colleagues (this issue) tackle the mind-boggling topic of mixed features in mania. They reveal that mixed features are relatively common in the context of mania and that these can impact treatment and outcome and therefore warrant routine clinical inquiry. Another attempt to disambiguate mixed mood states is described by Gin Malhi and colleagues (this issue), who additionally question the validity of DSM-5-defined mixed features. These are all weighty issues, as is the impact of growing obesity in bipolar disorder, a concern addressed by Emily Bernstein and colleagues (this issue) who hypothesise that perhaps disinhibition and the perception of hunger in bipolar disorder contribute to obesity in those with this illness.

It is clear from many Papers, Debates, Commentaries and Letters in the pages of ANZJP that few matters in psychiatry are as yet fully settled, and while this is perturbing, it does mean that we need to actively continue to search for clarity among the hype that besets our profession.