When assessing mood or formally rating the clinical symptoms of mood disturbance it is not uncommon to ask how an individual is feeling in comparison to their ‘usual self’. The assumption is that everyone is intrinsically able to gauge his or her mood and do so accurately. The difficulty however, is that mood fluctuates and is subject to modulation not only by contextual events but also by personality factors. In practice, this means that mood is often an unreliable indicator of clinical change and that it needs to be assessed carefully and repeatedly in order to be of discriminatory value when determining mental state psychopathology. It is therefore not surprising that mood disorders are described on the basis of syndromes rather than individual symptoms such as mood with equal if not greater reliance on additional symptoms such as guilt, hopelessness, changes in energy levels and ability to derive pleasure.

In recent years there has been increasing interest in subsyndromal mood symptoms and their impact on functionality. Separation of these from ‘normality’ and temperamental traits has also been explored. This is interesting and important research as it is literally ‘cutting edge’ in that it is attempting to define the boundaries of illness and that of normal experience itself.

In this issue of Acta Neuropsychiatrica, Dr Sara Reference Sara(1) addresses the broader issue of statistical normality in our one of our regular sections, Statistically Speaking. Grappling to some extent with this clinically, the original articles by Heinzel et al., Reference Heinzel, Northoff, Boeker, Boesiger and Grimm(2) De Macedo-Soares et al., Reference De Macedo-Soares, Brietzke, Da Silva Dias, Mendonca, Moreira and Lafer(3) and Larsen et al., Reference Larsen, Bendsen, Foldager and Munk-Jørgensen(4) each examine an aspect of mood, emotion or the clinical symptoms of depression. The exploration of this theme continues in the special section Intervention Insights by Tufrey and Coulston Reference Tufrey and Coulston(5) that examines cognitive remediation for bipolar disorder and the Comment and Critique by Baccaro et al. Reference Baccaro, Brunoni, Bensenor and Fregni(6) that reports on brain stimulation-induced hypomania in major depression. Brain stimulation is also the focus of Brain Bytes by Hoy and Fitzgerald Reference Hoy and Fitzgerald(7), which recounts succinctly the origins of brain activation in psychiatry.

Professor Gin S. Malhi ¹