Enseñanzas de una crisis
2. ANÁLISIS DE CONTEXTO
As we can see, uncertainties surrounding the appropriate classification of TTM provide an excellent opportunity to further its understanding. The purpose of this thesis is to present a comprehensive series of studies designed to investigate attitudes towards, and attentional biases in, TTM. In this thesis, we use data from self-reported hair-pullers sourced from online support sites as opposed to clinical samples. As reviewed in section 1.3 of this introduction, prevalence rates for TTM are still uncertain and studies (e.g., Duke et al., 2009; Duke et al., 2010b; Stanley et al., 1994) highlight the importance of sampling individuals from non-clinical samples.
The investigation of attitudes towards TTM is crucially important. As this chapter has shown, TTM research is relatively in its infancy and the condition merits more investigation. Chapter 2 will begin by introducing the role of stigma in mental health. Stigma from the public has been shown to promote isolation and barriers to treatment in those with mental health conditions (Botha & Dozois, 2015; Chan & Mak, 2015; Corrigan, 2004). Given the relatively low number of individuals who present for treatment with TTM, and those who receive an incorrect diagnosis from health professionals, we will first present a study investigating stigmatising attitudes towards TTM (along with other
conditions). It is possible that stigmatising attitudes towards TTM may be higher than that of other conditions and this in itself is important to investigate. This opening study will set the scene as to why it is important increase awareness and understanding of the under- researched condition of TTM.
We live in an environment where we are exposed to effectively unlimited stimuli, however, our brain has been conceptualised as a limited capacity processor (e.g., Moray, 1967). Classically, in order to deal with this sensory overload, Broadbent (1958) proposed the idea of a filtering system as way of selecting what is attended to. Essentially, to make sense of our environment, we selectively attend to some information more than others. It is beyond the scope of this thesis to consider the intricacies and various models of selective attention, and what will follow focusses on attentional bias.
An attentional bias reflects selective allocation of resources towards, or away from, a specific stimulus relative to other information that is accessible at the same time. A more detailed review of attentional biases will be presented throughout this thesis in the relevant chapters, however, in summary, attentional bias has shown to be important in the
maintenance of several mental health disorders and extensive evidence has consistently indicated the existence of strong attentional biases in: anxiety disorders (Dresler et al., 2009; Mathews & MacLeod, 1985); addictive disorders (Cane et al., 2009; Cox et al., 2006; Fadardi & Cox, 2009; Shiffman, Sayette, Paty, Gwaltney & Balabanis, 2003; Waters, Field, Munafo & Franken, 2009); and depression (Kerr, Scott & Phillips, 2005; Mitterschiffthaler et al., 2008).
Experiment 2 of Chapter 2, and the experiments in Chapters 3 and 4 of this thesis will focus specifically on attentional processing in people with TTM symptomology. In attentional bias research, various paradigms exist. Typically, these tasks measure reaction times where a participant has to respond to a trial as quickly as possible and their response is measured in milliseconds (ms). The time that is taken for the response is indicative of their attentional processing of the stimuli presented in the task. Attentional bias paradigms and corresponding literature will be reviewed in the context of the relevant chapters in this thesis, but an overview will be presented here.
The Stroop task (Stroop, 1953) requires participants to name the ink colour of a word while ignoring the meaning of the word. Responses are typically slower when the semantic meaning of the word is incongruent with the colour of the word presented (e.g., “blue” in red ink) compared with congruent trials (e.g., “blue” in blue ink). The modified emotional Stroop task (Mathews & MacLeod, 1985) expands on this by using words with emotional significance as stimuli (e.g., high and low valence words, high arousal words). Then there are lexical decision tasks, where participants are presented with a letter string and have to respond as quickly as possible as to whether it is a word (e.g., hair, died) or a non-word (e.g., clat, nump). Words yield a quicker response than non-words because the time taken to search one’s lexical memory for a non-word takes longer, before making a response.
To date, only a handful of studies have employed paradigms investigating attentional processing in TTM and this literature will be reviewed in detail in the relevant chapters. We use modified emotional Stroop tasks in Experiment 2 (shame-related words in Chapter 2) and Experiment 4 (hair-related words in Chapter 3). Experiment 2 in Chapter 2 will look more closely at the affective correlate of shame by investigating attentional bias to shame-related words in a TTM population, relative to a control group. While literature that will be reviewed in Chapter 2 has shown that people with TTM experience shame more than the general population, to our knowledge, Experiment 2 is the first study to investigate lower-level cognitive biases to shame in a TTM sample. As reviewed earlier in this introduction, TTMs often report negative affect both before and after hair-pulling episodes, and this may be reflected in an attentional bias towards shame- related stimuli in our TTM sample. Experiment 2 contributes to this literature by
presenting shame-related words (matched with positive and neutral words) in a modified emotional Stroop task to explore any differential attentional processing in people with TTM compared to a non hair-pulling control group.
Chapters 3 and 4 will move away from the theme of affective correlates (i.e., shame) towards the role of specific disorder-related stimuli, that is, hair-related stimuli. Chapter 3 presents three experiments that focus on the processing of hair-related words in a series of lexical studies. Experiment 3 in Chapter 3 uses hair-related words (matched with positive, neutral, and negative words) in a lexical decision task. Experiment 4 uses the same word-set in a modified emotional Stroop task. The aim of these studies is to identify any differences in the processing of hair-related words in a TTM group, relative to a non hair-pulling control group. Finally, Experiment 5 in Chapter 3 is a word-rating task where valence and arousal ratings are obtained for our hair-related words by both a TTM and control group.
The final experimental chapter, Chapter 4, develops from Chapter 3 by continuing to investigate attentional biases, but rather by exploring pictorial stimuli in a dot probe study using hair-related (and neutral) stimuli. Two images (one hair-related, one neutral) are presented simultaneously on either side of a fixation cross, competing for the viewer’s attention. Upon the disappearance of the two stimuli, a cue appears to either the left or the right of the screen, replacing one of the previously presented stimuli. The participant has to respond quickly as possible to the location of the cue. Our use of images in Chapter 4 increases the ecological validity of our hair-related stimuli. Dot probe literature will be reviewed in significantly more detail in Chapter 4 this section of the thesis.
In sum, the literature presented throughout this thesis will provide a review of evidence that biased attitudes and disorder-related attentional biases are present in several mental health conditions, and that these impact on the experience and maintenance of these conditions. With existing attitude and attentional research into TTM being scarce, this thesis will use a series of specific paradigms to out more about the nature of attitudes and biases towards, and in, TTM. Findings can contribute the understanding of factors that