Theoretical conceptualisations of firesetting by adults with intellectual disabilities: Development of a fire interest and attitudes assessment scale

Deliberate firesetting behaviour is an ongoing international problem, which has devastating consequences for victims and wider society. Adults with IDD who engage in firesetting have received little attention from researchers and practicing professionals, and this is particularly notable when the literature about firesetting is compared to other types of offending behaviour. The purpose of this thesis was to expand our knowledge and understanding of firesetting by adults with IDD across four separate but related studies.

The aim of Study 1 was to systematically examine and synthesise existing research to determine what was known about adults with IDD who set fires. The specific aims were to identify the prevalence of adults with IDD who set fires, highlight their characteristics and treatment needs, highlight offence related characteristics associated with deliberate firesetting, and evaluate assessment tools and interventions available to professionals working with this population. Several databases were searched for relevant articles, including PsychINFO, PsychARTICLES, Medline, CINAHL Plus with Full Text, Criminal Justice Abstracts, SCOPUS, Open Grey, and the University of Kent arson library. The methodological quality of studies was assessed using the Mixed Methods Appraisal Tool (Hong et al., 2018). Systematic searches of the literature resulted in 100 articles that met the specific inclusion criteria. Findings indicated that adults with IDD shared some characteristics with other adults who set fires (e.g., aggression, impulsivity). They also faced additional challenges, which may have implications for treatment and risk formulation (e.g., communication difficulties, lack of support). However, research was generally of poor methodological quality, limiting our ability to fully understand the characteristics and treatment needs of this population.

The aims of Study 2 were to validate Barnoux et al. (2015) and Tyler et al. (2014) micro-level theories of adult firesetting with a sample of adults with IDD who have set fires, and offer a preliminary unified descriptive model of the offence chain for adults with IDD who set fires. Thirteen adults with IDD in England were interviewed about the affective, cognitive, behavioural, and contextual factors leading up to and surrounding a recorded firesetting incident. Offence account interviews were analysed using a Grounded Theory approach. The resulting model consisted of four main phases: (1) background, (2) early adulthood, (3) pre-offence period, and (4) offence, and post offence period. The model accounted for prominent precursors to firesetting within this population including mental health deterioration, poor problem solving, and new motivations for firesetting. Unlike other offence chain theories, the Firesetting Offence Chain for Adults with IDD highlighted the significance of post offence behaviour and cognitions (e.g., an attempt to extinguish the fire).

The aims of Study 3 were to evaluate the accessibility of scales that appraised fire-related factors likely to be associated with firesetting behaviour for adults with IDD, and to develop an accessible self-report scale of fire-related factors likely to be associated with firesetting behaviour. Qualitative and quantitative data from three rounds of a Delphi exercise with practitioners and a focus group with adults with IDD were used to generate consensus about the accessibility of item adaptations made to the Fire Interest Rating Scale (Murphy & Clare, 1996), Fire Attitudes Scale (Muckley, 1997), and the Identification with Fire Questionnaire (Gannon et al., 2011). Findings suggested the accessibility of current measures could be improved to better meet the needs of adults with IDD, and adaptations to all questionnaire items were needed. Following feedback, revisions to current measures were implemented leading to the development of the Adapted Firesetting Assessment Scale for adults with IDD.

The aims of Study 4 were to investigate the reliability, validity, comprehensibility, relevance, and comprehensiveness of the Adapted Firesetting Assessment Scale when used with adults with IDD. Fifty-nine adults with IDD, some of whom had a history of firesetting completed the Adapted Firesetting Assessment Scale (AFAS) on two occasions. Feedback about the questionnaire was sought from both participants and professionals. The AFAS had acceptable internal consistency and good test-retest reliability. The attitudes towards fire, fire normalisation, poor fire safety subscales, and total scores discriminated firesetters from non-firesetters. Content analysis of feedback indicated the AFAS was easy to understand, relevant, accessible, and comprehensible. Findings offered some preliminary evidence to support the use of the AFAS with adults with IDD who have a history of firesetting.

The following conclusions were drawn from the combined findings. While there is evidence of a lack of research in this area relative to those without IDD, adults with IDD who set fires present with some prominent factors including circumscribed interests in fire or emergency services, negative social environments (including negative caregiver experiences and negative educational experiences), fire-related vulnerabilities (e.g., serious fire interest), or other vulnerabilities (such as other comorbidities, communication difficulties, and social exclusion). Adults with IDD also present with prominent motivations for setting a fire, including being motivated by a desire to express emotion, cause change, or illicit support from others. In addition, their cognitive and affective responses to starting a fire suggested adults with IDD had difficulties in understanding the consequences of their behaviour. From the findings, it can be concluded that the Adapted Firesetting Assessment Scale contributed towards the evidence base pertaining to the assessment of adults with IDD. Preliminary evidence suggested the Adapted Firesetting Assessment Scale was accessible, comprehensive, relevant, and reliable, and is likely a useful resource for future researchers and clinicians.