INTRODUCTION:Mental health problems are most prevalent during adolescence. Emotional granularity, the ability to identify distinctions between different emotion states in our mental experience, is said to contribute to the onset and maintenance of depression and anxiety in adults, through the evidence for its role in adolescent depression and anxiety is less well established. Theoretically, better emotional granularity facilitates adaptive selection and targeted deployment of emotion regulation strategies to manage negative emotions, thereby bolstering mental health. METHODS:In this mixed methods scoping review, 40 studies of emotional granularity in adolescents (aged < 25) were examined to establish: (i) how it is measured; (ii) its relationship with measures of anxiety/depression; and (iii) if it is related to and/or moderates the relationship between emotion regulation and anxiety/depression. Adolescent contributors with a lived experience of depression/anxiety were interviewed to gain their insights on emotional granularity. RESULTS:The review revealed: (i) the most common method of measuring emotional granularity was with ecological momentary assessment; (ii) good evidence that lower emotional granularity tracked greater levels of depressive symptomology, with less evidence for a relationship with levels of anxiety; and (iii) inconclusive evidence of granularity moderating the relationship between emotion regulation and depression/anxiety. Adolescent contributor views are presented, and knowledge gaps in our understanding and suggestions for further research are discussed. CONCLUSIONS:Emotional granularity well may be related to depression in adolescents, but crucially, there were few studies focussing on younger adolescents and no studies with adolescents diagnosed with anxiety or depression, so conclusions drawn are tenuous.

Emotional Granularity (EG) refers to the precision with which we describe and differentiate between our emotion states. Emerging evidence suggests that having poorer EG contributes to the onset and maintenance of psychiatric conditions such as depression. The likely mechanisms of action for this being that poor EG means inferior selection and deployment of relevant emotion regulation strategies to combat negative emotional turbulence. The following reviews research evidence for EG in adolescents (aged 14-24), specifically: (i) how it is measured; (ii) its role in anxiety and depression; (iii) its role as a moderator between emotion regulation and anxiety/depression. In addition, we spoke to adolescent stakeholders with a lived experience of anxiety/depression to gain their insights on EG.A literature review revealed 39 qualitative studies, however there were no studies that examined EG in adolescent populations with clinical diagnoses of anxiety or depression. In typical groups we found: (i) the most common method of measuring EG was with ecological momentary assessment methods; (ii) although there was good evidence that lower EG means greater levels of depressive symptomology, there was less evidence for EGs role in anxiety; (iii) inconclusive evidence of EG as a moderator between emotion regulation and depression/anxiety. Adolescent stakeholders had no difficulty understanding the concept of EG and believed it was one that young people would likely engage with. Importantly, they also felt it was a skill that has the potential to be improved. In sum, although EG shows promise as an active ingredient in adolescent depression, there is insufficient evidence for it playing a role in anxiety and inconclusive evidence of it as a moderator between emotion regulation and mental ill-health. Future studies, should both test EG’s role in depressed and anxious adolescent samples and investigate its potential to be trained.

Introduction. Decentering describes the ability to voluntarily adopt an objective self-perspective from which to notice internal, typically distressing, stressors (e.g. difficult thoughts, memories, and feelings). The reinforcement of this skill may be an active ingredient through which different psychological interventions accrue reductions in anxiety and/or depression. However, it is unclear if decentering can be selectively trained at a young age and if this might reduce psychological distress. The aim of the current trial is to address this research gap. Methods and analysis. Adolescents, recruited from partnering schools in the UK and the EU (n = 48 per group, age range = 16-19 years), will be randomised to complete of five-weeks of decentering training, or form an active control group that will take part in in light physical exercise and cognitive training. The co-primary training outcomes include a self-reported decentering inventory (i.e. the Experiences Questionnaire) and the momentary use of decentering in response to psychological stressors, using experience sampling. The secondary mental health outcomes will include self-reported inventories of depression and anxiety symptoms, as well as psychological wellbeing. The initial statistical analysis will use mixed-model analysis of variance (ANOVA) to estimate the effect of training condition on self-rated inventories across three timepoints: baseline, mid-intervention and post-intervention. Additionally, experience sampling data will be initially interrogated using hierarchical linear models. Ethics and dissemination. This study was approved by the Cambridge Psychology Research Ethics Committee, University of Cambridge (PRE.2019.109). Findings will be disseminated through typical academic routes including poster/paper presentations at (intern)-national conferences, academic institutes and through publication in peer-reviewed journals.