Impulsivity and self-harm in adolescence

This thesis explores the relationship between dimensions of trait impulsivity and self-harm outcomes in school and college-based young people, drawing on a multi-method approach. Adolescence, and in particular early to mid-adolescence, is a vulnerable time for developing self-harm and this vulnerability may be amplified by levels of impulsivity and emotional reactivity which are also elevated during this period. Impulsivity is a broad, multi-faceted construct, the various dimensions of which have historically included the failure to analyse and reflect before engaging in behaviour, or to adequately think through the consequences of action. Recently, emotion-based dispositions towards rash action (Negative and Positive Urgency) have been differentiated from other non-emotion-based forms of impulsivity. Considerable empirical and theoretical work has implicated impulsivity across a range of problem behaviours in youth, yet the relevance of the construct in understanding and identifying behaviour engagement has been hampered by a failure to adequately specify which dimension of impulsivity is associated with the outcome of interest. Research is starting to specify with greater precision how impulsivity relates to self-harm behaviour in youth. This work is facilitated in large part by the delineation of unidimensional impulsivity traits within the UPPS-P (Urgency-Premeditation-Perseverance-Sensation-Seeking) Impulsivity model (Lynam, Whiteside, Smith, & Cyders, 2006; Whiteside & Lynam, 2001). The present thesis aims to contribute to this emerging body of work by empirically examining how unidimensional impulsivity traits are implicated in adolescent self-harm across different developmental stages and within cross-sectional, prospective and qualitative designs. As such, the work aims to deliver a body of evidence to guide future intervention and prevention work in this field. Ethical reflexivity should be central to any research endeavour and is particularly pertinent within the field of mental health. Additionally therefore, the thesis has engaged with the ethical impact of this body of work on the young people involved. The thesis begins by providing an overview of approaches to defining and measuring impulsivity in Chapter 1 and introduces the UPPS-P Impulsivity model. This chapter also explores emotion-based impulsivity in more detail and the potential mechanisms which underlie its importance. Chapter 2 examines self-harm and the relevance of this behaviour in adolescents. Key explanatory models of self-harm are described in this chapter and theorised links with impulsivity are discussed. Chapter 3 brings the preceding chapters together within a systematic review of the literature as it relates to self-harm and impulsivity in adolescents aged 11-24 years. Chapters 4 and 5 present research from the SHIP-SHAPE (Self-Harm and ImPulsivity in ScHool Aged young PeoplE) school study in which students aged 13-15 years completed a self-report questionnaire at two time points three months apart. The research sought to clarify concurrent (Study 1.1 within Chapter 4) and predictive (Study 1.2 within Chapter 5) relationships between dimensions of impulsivity and distinct categories of self-harm thoughts and behaviours. Logistic regression analyses in Chapter 4 confirmed that young people with a history of self-harm were impulsive, and this impulsivity related chiefly to emotional response. Negative Urgency also distinguished those who had self-harmed, from those who had thought about self-harm but not acted on their thoughts. However, more recent and frequent patterns of self-harm were better characterised by deficits in conscientiousness, or sensation-seeking. Analyses in Chapter 5 revealed that those who maintained their behaviour over the course of the study tended to respond impulsively to emotion, but first onset of behaviour during the study period was predicted by rash but not emotion-driven risk-taking. Chapter 6 presents additional findings from the SHIP-SHAPE school data (Study 2), which revealed the impact of participation via multi-methods analysis of mood-change scores, survey ratings, and open comments. Overall findings suggested that most young people valued participation and cited important benefits, but impact variations according to gender, self-harm status, and time of assessment were revealed. Chapters 7 and 8 present research from two Further Education College-based studies with adolescents aged 16-22 years. Each drew on separate methods to consider the interplay between dimensions of impulsivity and the broader cognitive context. Analyses in Chapter 7 using self-report survey data confirmed the concurrent relationship between self-harm and Negative Urgency (Study 3.1). Evidence also indicated an important transactional relationship, finding that low self-control and Negative Urgency, increased the risk of more frequent self-harm. Chapter 8 presents findings from Study 3.2, a qualitative study which examined the ways in which a multidimensional account of impulsivity, alongside other affective and cognitive factors, was meaningful to individual understandings and experiences of self-harm. Data was captured by exploratory card-sort tasks and face-to-face interviews. Dynamic processes associated with rash reactivity to emotion, inadequate deliberation, anger and low control were recognised as proximal and distal risk factors for self-harm. Together the studies support the utility of unidimensional facets of impulsivity in distinguishing distinct components of self-harm thoughts and behaviours across early and mid-to-late stages of adolescence. In particular, evidence supports the central role of emotion-based impulsivity in heightening risk for self-harm across adolescence. However, cognitive deficits may have a crucial role to play in exacerbating risk once self-harm behaviours are established. Moreover, multi-method data suggests that affect-driven responses and inadequate or over-taxed cognitive systems are likely to produce heightened risk profiles. The findings have implications for the delivery of research and interventions, primarily by demonstrating the utility of a short and relatively burden free impulsivity tool, which may be effective in specifying treatment and intervention targets in adolescents. Additionally, the work has ethical implications for conducting of self-harm research in schools and for facilitating the involvement of young people in research