Aggressive behaviour

Aggression can be defined as either verbal (e.g. verbal threats or derogatory statements towards others) or physical behaviour (e.g. hitting, biting, kicking or throwing objects at others) that may result in harm or injury to another individual (Fitzpatrick Reference Fitzpatrick, Srivorakiat and Wink2016). Although estimates vary, studies have shown that between 22 and 56% of children diagnosed with ASD exhibit aggression (Kanne Reference Kanne and Mazurek2010). It is essential to treat aggressive behaviour, as it is associated with several adverse outcomes, such as increased use of psychotropic medications, parental stress, educator burnout, relationship deficits and an increased risk of physical abuse (Fitzpatrick Reference Fitzpatrick, Srivorakiat and Wink2016).

Non-compliant behaviour

Non-compliant behaviour is generally marked by a failure to respond with desired and appropriate behaviour when presented with a request (Luiselli Reference Luiselli and Matson2009). Non-compliance may include a ‘passive response’ in which the individual fails to follow through with instructions, although this is often accompanied by other challenging behaviours, such as aggression or property destruction (Luiselli Reference Luiselli and Matson2009: p. 176). Prevalence rates between 25 and 65% are reported by studies of children and adolescents without disabilities (Kalb Reference Kalb and Loeber2003). However, non-compliant behaviours can be especially alarming for caregivers of children with developmental disabilities, as they are associated with poor academic progress and delays in acquiring new skills (Lipschultz Reference Lipshultz and Wilder2017a).

Property destruction

Property destruction can be considered a subcategory of aggressive behaviour. Whereas aggressive behaviour is generally directed towards others, property destruction is directed toward objects and includes damaging personal or public property through tearing, hitting, breaking or kicking objects (Didden Reference Didden, Sturmey, Sigafoos and Matson2012). As previously noted, it is important to treat behaviours involving property destruction, as they are associated with increased caregiver stress, an increased likelihood of out-of-home placements and of psychotropic medication use, and interference with educational instruction (Didden Reference Didden, Sturmey, Sigafoos and Matson2012).

Self-injurious behaviour

Self-injurious behaviour (SIB) is characterised as behaviour directed towards one's own body that can result in harm or tissue damage (Summers Reference Summers, Shahrami and Cali2017). SIB has been reported to occur in approximately 50% of children with ASD and can present on continua of both severity and frequency, ranging from mild forms (e.g. head rubbing, thigh slapping) to severe forms of behaviour (e.g. head banging, eye poking, rumination) (Summers Reference Summers, Shahrami and Cali2017). Among individuals with ASD and intellectual disability, head banging has been reported as the most common form of SIB, although other forms include head hitting, hair pulling, rumination and pica. SIB can cause serious concerns related to the individual's safety, as well as an increased risk of hospital admission, the use of mechanical and/or physical restraints and psychotropic medication use (Didden Reference Didden, Sturmey, Sigafoos and Matson2012).

Stereotypical behaviour

Stereotyped behaviour, defined as repetitive vocal or motor behaviours, are a characteristic feature of ASD (American Psychiatric Association 2013). Some of the most common forms of stereotypical behaviour include body rocking, spinning, repetitive hand movements and posture abnormalities (APA 2013). Although typically developing children may display repetitive motor movements, these often diminish with age and do not interfere with daily living. Compared with other common challenging behaviours, stereotypical behaviour has been considered less problematic. However, engagement in stereotypical behaviours by those with developmental disabilities can impede skill acquisition, be socially stigmatising and may develop into self-injury and other forms of challenging behaviour (Didden Reference Didden, Sturmey, Sigafoos and Matson2012).

Toe-walking behaviour

Toe-walking refers to ambulatory stance in which individuals walk with a toe-to-toe gait, without making heel contact with the ground (Sala Reference Sala, Shulman and Kennedy1999). Although toe-walking can be present in typically developing children in early childhood, it is not considered to be problematic until after 2 years of age. Toe-walking commonly affects children diagnosed with ASD, with a prevalence rate of nearly 20.1% (Barrow Reference Barrow, Jaworski and Accardo2011). Toe-walking can be caused by spinal or muscular abnormalities, although its cause is often unknown in individuals with ASD (Sala Reference Sala, Shulman and Kennedy1999). Assessment and intervention targeting toe-walking are beneficial, as it can lead to medical difficulties (e.g. foot and ankle abnormalities or pain, limping, bunions), social stigmatisation or reduced exercise if left untreated (Caserta Reference Caserta, Pacey and Fahey2019).

Transition-related challenging behaviour

Resistance to change, including extreme distress at small changes and adherence to specific routines, are distinctive features of ASD (APA 2013). Challenging behaviours often occur as a result of resistance to change and can intensify if they are not treated (Neil Reference Neil and Sturmey2014). These transition-related challenging behaviours can adopt multiple topographies, including destructive behaviour (e.g. aggression, property destruction), elopement (e.g. leaving a designated area without permission) or uncooperative behaviour (e.g. tantrum or dropping behaviours) (Lehardy Reference Lehardy, Lerman and Evans2013). Transition-related challenging behaviours can present safety concerns and can interfere with educational and social opportunities in the classroom (Varni Reference Varni, Lovaas and Koegel R1979).

Indirect assessment

Several tools have been developed to properly assess challenging behaviours in those with developmental disabilities. It is essential to identify the function of presented challenging behaviours so that an appropriate behavioural intervention plan can be developed. The first step in identifying the function of challenging behaviours is often the use of indirect assessment tools. These tools typically consist of interviews, rating scales or questionnaires rated by caregiver informants (e.g. parents or teachers) to obtain information about challenging behaviours and the environmental context in which they occur. Several such assessment tools are available, some of which assess the topography, intensity and frequency of the behaviours while others assess their function (Cividini-Motta Reference Cividini-Motta, Bloom, Campos and Matson2017). Table 1 presents key details regarding a number of rating scales available for the former purpose.

TABLE 1

Rating scales to assess the severity, frequency and topography of challenging behaviours

Although the scales identify the topography, severity and frequency of challenging behaviours, other measures provide indirect assessment of behavioural function. The Functional Assessment Interview (FAI; O'Neill Reference O'Neill, Albin and Storey2015) is a semi-structured interview that consists of 11 sections designed to acquire information about setting events (events that ‘set off’ the behaviour), the immediate antecedent (trigger) and consequences of the behaviour, as well as the possible function(s) maintaining the behaviour. Additionally, information about the individual's communication skills, the efficacy of the behaviour (e.g. amount of effort required, reward frequency), preferred rewards and activities, and previous behavioural intervention strategies is collected to formulate hypotheses about the behaviour. Unlike other indirect measures of behavioural function, the FAI does not produce a score to aid in differentiating a behaviour's functions; however, it provides useful qualitative information for intervention planning (O'Neill Reference O'Neill, Albin and Storey2015). Several brief structured rating scales for assessing the function of behaviour are also available (Table 2).

TABLE 2

Rating scales to assess the functions of challenging behaviours

Direct assessment

Direct assessment requires observation of challenging behaviours in the setting in which they take place, such as the school, home or clinic (Cividini-Motta Reference Cividini-Motta, Bloom, Campos and Matson2017). Direct observation techniques and obtaining quantifiable data can be essential to the development of treatment plans to reduce target behaviours (Cohen Reference Cohen, Yoo, Goodwin, Matson and Sturmey2011). Clinical psychologists primarily use indirect rating scales, whereas psychologists in special education and school psychology may espouse an applied behaviour analysis method to assess challenging behaviours. These direct assessment techniques include constructing operational definitions, antecedent–behaviour–consequence recording and experimental functional analyses (Cohen Reference Cohen, Yoo, Goodwin, Matson and Sturmey2011).

The initial step in direct observation involves the formation of an operational definition of the target behaviour to obtain reliable data. When creating the operational definition, clinicians should describe the target behaviour in detail to prevent disagreement between observers. Rather than identifying the category of a target behaviour (e.g. aggression), the topographies (e.g. hitting, slapping, kicking) should be listed to ensure that the target behaviour can consistently be observed and measured. For example, for one child aggression might consist of multiple behavioural topographies, including biting, hitting and kicking. However, another might engage in just one behavioural topography (e.g. kicking) that serves multiple functions (Cohen Reference Cohen, Yoo, Goodwin, Matson and Sturmey2011).

One of the most widely used forms of direct assessment is known as antecedent–behaviour–consequence (ABC) recording. This form of recording involves tracking the antecedent (events preceding the target behaviour), the target behaviour and the consequence (events following the target behaviour) in a narrative format. These data can aid in hypothesising the function of the target behaviour, as well as identifying any strategies that may reduce the challenging behaviour in the future. ABC recording is frequently used, as it is time effective and requires minimal training. Scatterplots are another descriptive direct assessment method. They can be used to identify time periods that may be associated with challenging behaviours, although they do not assist with the identification of functions maintaining the behaviours (Cividini-Motta Reference Cividini-Motta, Bloom, Campos and Matson2017).

Other direct assessment techniques involve collecting quantifiable data and, in such cases, specifying the procedures for recording observations, length of time for observations and interval between sessions is crucial. One form of collecting data, continuous recording, involves tracking one or more dimensions of a challenging behaviour each time it occurs. These dimensions include frequency, duration, latency, intensity and physical impact (e.g. whether bruising is caused). Continuous measurement systems allow for a comprehensive record under observation. For example, a clinician may track the frequency of a target challenging behaviour (e.g. tantrum behaviour) using a hand-held counter or electronic counting system. Clinicians may use duration recording for behaviours that are non-discrete, such as persistent mouthing of objects, to track the total amount of time the individual engaged in the behaviour during an observation period. Latency recording tracks the time between the occurrence of an antecedent event and the child starting (or ceasing) to engage in the behaviour of concern. Continuous observation and recording can be difficult and demanding, and as a result several methods (e.g. partial interval recording, whole interval recording and momentary time sampling) have been developed to provide estimates of levels of behaviours while reducing demands on the observer (Cohen Reference Cohen, Yoo, Goodwin, Matson and Sturmey2011).

Following the use of scales or interviews and direct observation methods, an experimental functional analysis (EFA) may be conducted to identify the definite function that a target challenging behaviour serves (Cividini-Motta Reference Cividini-Motta, Bloom, Campos and Matson2017). The completion of an EFA is considered best practice in the field of applied behaviour analysis, as it allows for function-based treatment plans. Unlike other forms of descriptive direct assessment, such as ABC recording, EFAs experimentally manipulate the antecedents and consequences of a target behaviour in both control and test conditions (Cividini-Motta Reference Cividini-Motta, Bloom, Campos and Matson2017). Although EFAs are beneficial in developing function-based treatments, they can be impractical to complete in everyday clinical practice as they require specialised training and can be time intensive. As a result, alternative indirect methods that provide information about the functional variables maintaining behaviours, such as the Questions About Behavioral Function (QABF) checklist or Motivation Assessment Scale (MAS) (Table 2), can be especially useful for clinicians.

Behavioural intervention

The most widely investigated treatment option for ASD is applied behaviour analysis, which provides the basis for several evidence-based interventions for challenging behaviours. Applied behaviour analysis strives to use the least restrictive intervention. Several non-aversive behavioural interventions have been found to be efficacious in reducing challenging behaviour. Behavioural interventions generally consist of both antecedent-based and consequence-based strategies (Lipshultz Reference Lipshultz and Wilder2017a). Antecedent-based strategies are interventions that modify environmental stimuli to prevent the occurrence of challenging behaviour, whereas consequence-based strategies involve modifying contingencies of reinforcement in the environment to promote the reduction of challenging behaviour (Cividini-Motta Reference Cividini-Motta, Bloom, Campos and Matson2017).