The presence of challenging behaviour, evident in various forms, in children who have a developmental or intellectual disability is apparent throughout the literature (Adams & Allen, 2001; Allen et al., 2007; Einfeld & Tonge, 1996; Emerson, 2003; Goodman & Linn, 2003; Hastings, 2002; Kopp, 1990; McWilliam & Bailey, 1995; Mundy & Kasari, 1990; Quine, 1986; Roberts, Mazzucchelli, Studman, & Sanders, 2006; Roberts, Mazzucchelli, Taylor, & Reid, 2003; Tomporowski & Hager, 1992; Van Nieuwenhuijzen, De Castro, Wijnroks, Vermeer, & Matthys, 2004). For example, Allen et al. (2007) identified that challenging behaviours are evident in 10-17% of people with intellectual disabilities. McCarthy (2007) also acknowledged the heightened prevalence of behavioural disorders in those with intellectual and developmental disability, which appears to be more evident in children than adults. For example, Einfeld and Tonge (1996) found that challenging behaviours of an emotional or behavioural nature were evident in four out of ten (40%) children with intellectual disabilities. Quine (1986) identified that 64% of children aged 3-5 with developmental disability exhibit challenging behaviour. Other studies have found that 45 and 50% of children with developmental disabilities demonstrate challenging behaviour or a behavioural disorder (Corbett, 1985; Rutter, Tizard, Yule, Graham, & Whitmore, 1976).
Research has also identified the variety of challenging behaviours in children with developmental disabilities. In a sample of children with intellectual disabilities and challenging behaviour, 75% exhibited aggressive behaviours that were rated as moderate or severe. Threats to the safety of the child or someone else were identified in 87% of families as the most serious behaviour they had dealt with (Allen, Hawkins, & Cooper, 2006). A child’s challenging behaviours can also be multiple and varied based on their situation. For example, Pithouse and Lowe (2008) found an average of 21 challenging behaviours for children. Piling, McGill, and Cooper (2007) reported that on average, children with intellectual disabilities attending residential day schools, displayed 10.8 various types of challenging behaviours (Piling, McGill, & Cooper, 2007). Challenging
behaviours such as self-injury and stereotyped behaviour are the two most commonly researched behaviours evident in those with developmental disabilities (Bodfish, 2007).
Theorists offer varied explanations for this significant correlation between developmental disability and challenging behaviour. For children with behavioural, social and emotional difficulties, even small things easily tolerated by the majority of children can provoke anxiety and result in the production of inappropriate outbursts or behaviours (Howarth, 2008). Thus having a disability or existing difficulty of a social, emotional or behavioural kind may work to lower tolerance levels and enhance inappropriate behavioural responses (Roberts, Mazzucchelli, Taylor, & Reid, 2003). Imray (2008) and Gallico, Burns, and Grob (1988) offer an explanation for this correlation in proposing that a lot of people with learning difficulties have problems expressing their needs. It is hard enough for a child with a learning disability and communication issues to address their basic needs such as asking for food when hungry, let alone expressing and understanding their emotional state appropriately. Frustration begins to build up, and a child begins to feel increasingly isolated, as if they are not achieving and do not belong (Gallico, Burns, & Grob, 1988). Imray (2008) points out that it is likely that the more severe the communication impairment or inability to get needs met, the greater the likelihood for the development of challenging behaviour. Learning difficulties may also reduce self-esteem and limit reflection on such things as emotional states and behaviour. Because of this, there is potential for less understanding and tolerance for others’ behaviours and emotions (Imray, 2008).
An emotional perspective on the correlation between challenging behaviour and developmental disability is also described in the literature. For example, some authors note a frequent experience of failure and rejection, which children use in a repetitive, maladaptive sequence to problem solve (Zigler, 1999). One study found that 40% of children with developmental disabilities engaged in a form of destructive challenging behaviour at least once every day (Dunlap, Robbins, & Darrow, 1994). Challenging behaviour in children with developmental disabilities has been found to serve two social purposes: social attention-seeking and social avoidance (Taylor & Carr, 1992). These children may be constantly put in situations in which their frustration at being given tasks which are not suited to their developmental level becomes apparent through their behaviour. In fact these ‘challenging’ behaviours may actually be viewed as adaptive
responses to a world that is difficult to adapt too (Goodman & Linn, 2003). Conditions of poverty also appear to be related to the onset of both developmental disability and challenging behaviours through exposure to undesirable environmental conditions. Exposure to the metal lead in the environment and subsequent elevated blood lead levels has an impact on the development of children. This impact is evident in brain (Boivin & Giordani, 1995) and, cognitive development (Tong, 1998) as well as lower emotional regulation, destructive behaviours and withdrawn tendencies (Mendelsohn, Dreyer, Fierman, Rosen, Legano et al., 1998; Wasserman, Staghezza-Jaramillo, Shrout, Popovac, & Graziano, 1998).
Although research has clearly identified many links between challenging behaviour and developmental disability, this does not imply that if a child has one difficulty they also have the other, as often this is not the case. Also these correlations do not necessarily suggest that when a child does have these difficulties (developmental disability and challenging behaviour), research and treatment for this population integrates both difficulties. Traditionally, the disorder-specific behaviour or additional challenging behaviours have been focussed upon neglecting other components of a child’s presentation, such as emotional factors underlying behaviour. Therefore, a review of traditional approaches and the progression toward new theory solidifies the need for the current study.