One of the most strongly held beliefs in developmental psychiatry is that various emotional, cognitive, behavioural and temperamental factors observed in childhood set the individual trajectory for the risk of onset, course and likely response to treatments in youth and adults with depressive and other mood disorders (Hickie et al., 2019).
The potential relationships between traumatic experiences and the onset and course of major mood disorders have always been controversial. Some experiences, most notably physical or sexual abuse, as well as substantive bullying in childhood, are clearly recognised as major risk factors for a range of mental disorders, as well as a range of linked phenomena including self-harm and suicidal behaviours (McKay et al., 2021; Zatti et al., 2017). There is considerable interest and ongoing research into how these adverse experiences come to be ‘encoded’ via neurobiological or genetic mechanisms that then transmit those effects into later-onset major mental disorders, substance misuse or other self-harming behaviours (Maddox et al., 2019).
In recent years, there has been considerable enthusiasm among research groups focused on developing novel therapies for treatment-resistant depression, and a wider community that has had experiences using recreational drugs, in more systematic evaluation of the therapeutic value of these compounds (Goodwin et al., 2022; Young, 2023). This has also been associated with advocacy for decriminalization, legalization and possible public licensing for their ‘medicinal’ use (Siegel et al., 2023).
One of the greatest global threats to mental health and wellbeing is the already discernible impact of climate change on local communities, particularly those living in the most vulnerable places on the planet, as well as the predicted impacts globally over the next 25–50 years (Romanello et al., 2021). Impacts have already been reported in those communities which have been devastated, often repeatedly, by extreme weather events (floods, cyclones, drought, bushfires, etc.) (Obradovich et al., 2018). These include massive social dislocation, loss of social connections and breakdowns in education, employment, economic and housing security – all factors known to increase the risk of common mental health conditions including anxiety, depression and other mood disorders.
One of the long-standing challenges in the field of depressive and other mood disorders is to have a clear conceptualisation of the relationships between childhood temperaments, personality development and adult self and interpersonal function, and depressive and other mood disorders. Some biologically-based dispositional (or temperamental) traits are present from birth and are relatively stable from infancy through to adulthood. These characteristics (e.g., anxious attachment or social inhibition) are commonly seen as ‘at-risk’ traits for later formal diagnoses of anxiety disorders in pre-pubertal children and anxiety and depression in teenagers (Compas et al., 2004; Rothbart, 2007).
The advent of new non-invasive (largely EEG and MRI-based) methods for recording the activity of critical brain circuits (frontotemporal and subcortical) and networks (Default Mode, Salience, Central Executive), cross-sectionally and longitudinally, as well as concurrently (EEG and fMRI), has led to a focus on whether such techniques could be used to guide individual treatment selection. While this work has commenced with specific relevance to depression and other mood disorders (Goldstein-Piekarski et al., 2022; Hack et al., 2023; Scangos et al., 2023), there is still much to be learnt and a great need to replicate findings across different cohorts and different research centres.
One of the areas of greatest public interest is whether altering your diet can reduce your risk of developing depression and whether there are any dietary manipulations that are effective treatments for depression? Many epidemiological studies have suggested associations between lower rates of depression and specific dietary types (e.g., Mediterranean, ‘anti-inflammatory’, Keto, low carbohydrate and Fish oil-rich) (Dietch et al., 2023). These epidemiological data are buttressed by post hoc analyses of several large-scale clinical trials with other primary outcomes – the PREDIMED study being an exemplar (Sánchez et al., 2013). In addition, the first generation of randomised controlled trials is now available suggesting that a healthier diet pattern especially the Mediterranean diet reduces the symptoms of depression in clinical populations (Jacka et al., 2017).
The most basic distinction between depressive (and other mood) disorders and other major mental disorders is the notion that they are primarily mood or affective disorders and not fundamentally perturbations of other cognitive, perceptual, motor, communication, impulse, sleep−wake, fear-response, arousal, developmental or personality functions. The primacy of mood or affective state is captured in the ‘core’ criteria for major depression (depressed mood or loss of pleasure) and the other major mood disorders (e.g., for dysthymia – prolonged depressed mood) (American Psychiatric Association, 2013). For bipolar disorder, while the presence of manic features (with increased motor activity) (Scott et al., 2017) is the core element, the depressive phase is described in similar terms, with the emphasis on the same shared features of major depression (i.e., depressed mood or loss of pleasure).
