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International Journal of Developmental Disabilities logoLink to International Journal of Developmental Disabilities
. 2016 Aug 18;64(1):45–52. doi: 10.1080/20473869.2016.1221233

Challenging behavior, functioning difficulties, and quality of life of adults with intellectual disabilities

Ayelet Gur a,*
PMCID: PMC8115461  PMID: 34141290

Abstract

Objective: The current study aimed at examining the correlations between challenging behaviors, difficulties in functioning, and quality of life in institutionalized adults with intellectual disabilities.

Methods: A sample of 53 people with intellectual disabilities and challenging behavior who resided in a large institutional care facility was recruited. The research questionnaire included the following instruments: (1) The challenging behavior scale; (2) The World Health Organization Disability Assessment Schedule 2.0; and (3) The Personal Well-Being Index.

Results: No significant correlation was found between challenging behavior and quality of life. However, more challenging behavior found to be correlated with greater difficulties in functioning. Furthermore, a weak correlation was found between difficulties in functioning and quality of life. Participants who had greater difficulty functioning tended to exhibit lower levels of quality of life. No significant associations were found between the sample’s personal characteristics (gender, age, and the severity of intellectual disability) and challenging behavior, difficulties in functioning, and quality of life.

Conclusion: Empowering personal functioning of people with intellectual disabilities is important in planning rehabilitation interventions. Such interventions are likely to promote a higher quality of life. There is the need for future research to further investigate the relationship found in this study.

Keywords: intellectual disability, challenging behavior, functioning, quality of life

Introduction

Although there are many studies about the quality of life of people with intellectual disabilities, few empirical studies have focused on the additional impact of challenging behaviors (Morisse et al. 2013). A critical review of the research on treatments for challenging behavior has revealed that quality of life as an outcome of behavioral interventions is rarely reported (Grey and Hastings 2005). Moreover, the effect of challenging behavior on quality of life has not been examined with regard to the difficulties people have in functioning. The current study aims to fill these gaps by exploring the correlations between challenging behavior, difficulties in functioning, and quality of life in institutionalized adults with intellectual disabilities.

Background

The concept of quality of life

The concept of quality of life, which represents the overall assessment of human experience (Costanza et al. 2007), has been of great interest among scholars and professionals for many years (Schalock et al. 2010; Veenhoven 2000). Quality of life is considered a universal concept relevant to all people in any culture (Schalock et al. 2002; Skevington et al. 2004), including individuals with disabilities in general and those with intellectual disabilities in particular (Cummins 2005; Rapley 2003).

However, there is no agreed-upon definition or standard of measurement (International Wellbeing Group 2013). Most quality of life perspectives in the intellectual disabilities field fall into one of four approaches (Felce and Perry 1995). First, the objective approach defines quality of life as the quality of the individual’s living conditions. Although the number of quality of life dimensions varies slightly, most conceptions include general well-being, positive social involvement, and opportunities to achieve personal potential (Schalock et al. 2002). Note that the objective approach has been criticized for not considering that individuals differ in their perceptions of what is important and satisfying (Nota et al. 2006).

Second, the subjective approach claims that quality of life is the individual’s overall satisfaction with his/her life. This approach is perceived as lacking because individuals tend to adapt to the conditions of their lives, even to negative experiences (Brickman and Campbell 1971; Headey and Wearing 1992; Nota et al. 2006; Suh et al. 1996). The third approach combines the objective and subjective elements, and defines quality of life as a combination of living conditions and satisfaction with life (Borthwick-Duffy 1992; Cummins 2000; Dijkers 1997). The fourth approach (Felce 1997; Felce and Perry 1995; World Health Organization [WHO] 1997) suggests that there is a need to consider the importance of each domain for each individual.

Quality of life of people with intellectual disabilities

Sheppard-Jones et al. (2005) reported that adults with intellectual disabilities had a lower quality of life than the general population. Other researchers have separated the objective and subjective dimensions. For example, Cummins et al. (1997) found that in terms of objective quality of life, those with intellectual disabilities had significant disadvantages overall, with lower scores in material well-being, health, intimacy, and emotional well-being. However, assessments of their subjective quality of life did not reveal this effect. Similarly, Hensel et al. (2002) demonstrated that people with intellectual disabilities had a lower objective quality of life, scoring lower than those without intellectual disabilities with regard to their health, productivity, community, and emotional well-being.

Challenging behavior of people with intellectual disabilities

Challenging behavior is an umbrella term for different types of behaviors that challenge services (Bell and Espie 2002; Emerson 1995) and is a socially constructed concept (Banks et al. 2007; Lowe and Felce 1995) that describes a range of behavioral disorders. Challenging behavior includes behaviors either harmful to the individual, challenging for those providing care to the individual, or considered objectionable by the public (Emerson and Einfeld 2011), or any combination thereof. The most common definition of challenging behavior cited in the literature holds that it is:

Culturally abnormal behavior(s) of such an intensity, frequency or duration that the physical safety of the person or others is likely to be placed in serious jeopardy, or behavior which is likely to seriously limit or deny access to and use of ordinary community facilities. (Emerson 1995, p.4)

Its prevalence varies between 10 and 15% among people with intellectual disabilities (Emerson et al. 2001), which is higher than in the general population (Matson and Boisjoli 2009). Studies indicate that challenging behavior is positively related to the severity of intellectual disabilities (Emerson and Bromley 1995; Emerson et al. 2001) and that it is a chronic condition, meaning that those with intellectual disabilities who are diagnosed with challenging behavior continue to display such behavior several years later (Chadwick et al. 2005; Murphy et al. 2005; Totsika et al. 2008). Nevertheless, therapeutic strategies have been shown to reduce challenging behavior (Didden et al. 2006; Hassiotis et al. 2009). Challenging behavior has a significant impact on people’s lives and can interfere with their development, harm their social functioning, and reduce their quality of life (Holden and Gitlesen 2006).

Difficulties in functioning of people with intellectual disabilities

According to the American Association of Intellectual and Developmental Disabilities,1 intellectual disabilities are characterized by limitations in adaptive behavior, i.e. the variety of skills that are learned and used by people in their everyday lives, including activities of daily living (ADL). Furthermore, difficulties in functioning are affected by challenging behavior (Matson and Boisjoli 2009) and influence the quality of life (Holden and Gitlesen 2006).

According to the International Classification of Functioning, Disability, and Health (ICF) developed by the WHO, the term ‘functioning’ is defined as a ‘generic term which includes body functions and structures, activities and participation. It indicates the positive aspects of the interaction between the individual (with a health condition) and its context factors (personal and environmental factors).’ The term ‘disability’ refers to impairments, limitations on activities, or restrictions on participation (WHO 2001, pp.212–213). People with intellectual disabilities tend to have greater functioning difficulties that may limit them from independently performing basic ADL or other tasks essential for independent living (Irazábal et al. 2012).

Challenging behavior, difficulties in functioning, and quality of life

Challenging behavior threatens the individual’s quality of life (Banks et al. 2007). It is associated with difficulties in functioning in a broad range of areas of life such as leisure, work, and social life that influence quality of life (Gerber et al. 2008; Hastings 2002; Totsika et al. 2010). Thus, it is reasonable to assume that challenging behavior has an indirect effect on quality of life. For instance, activities such as self-injury and aggression can seriously damage people’s health and functioning, which, in turn, may affect their quality of life (Emerson and Einfeld 2011). Furthermore, challenging behavior can significantly impact the development and display of appropriate social skills. Studies have demonstrated that people with intellectual disabilities and challenging behavior score lower than their peers without such issues with regard to their social skills (Kearney and Healy 2011). Social skills shown to have a dramatic influence on quality of life; a sense of closeness and affiliation with others on a daily basis contributes to well-being and positive interactions, both of which are strong predictors of quality of life (Mayers 2003; Reis et al. 2000).

A broader perspective argues that the most important aspect of quality of life is social inclusion, and that people with intellectual disabilities and challenging behavior are at greater risk of exclusion from society (Murphy 2009). It is well documented that severe challenging behavior can result in institutionalization for many years (Emerson 1995) and exclusion from community-based services (Allen et al. 2007; Borthwick-Duffy et al. 1987). More specifically, studies in Israel have documented that challenging behavior harms people’s chances for community living (Gur et al. 2015; Nissim et al. 2011). Furthermore, living in an institutional setting correlates with a poor quality of life (Emerson et al. 2000; Kozma et al. 2009; Mansell et al. 2001).

While challenging behavior is negatively correlated with quality of life, studies have shown that people with intellectual disabilities and behavioral disorders have more functioning difficulties than people who have only intellectual disabilities (Irazábal et al. 2012). For example, among adolescents with challenging behavior in special education settings, their behavior appears to be a strong predictor of their dysfunction across all areas of life, indicating that those who engage in such behavior have poorer functional outcomes (McGeown et al. 2013).

As aforementioned, challenging behavior is associated with both greater difficulties in functioning and lower quality of life. Nonetheless, evidence exists that difficulties in functioning and quality of life are also correlated. Persons with intellectual disabilities often experience difficulty in functioning in their daily lives (Kottorp et al. 2003). The ability to perform ADL tasks independently, confidently, efficiently, and with minimal effort is essential for this population and affects their quality of life; deficits in these skills are a primary impediment to independent living (Soenen et al. 2009). Furthermore, studies have demonstrated a connection between greater physical dependency and a low quality of life (Gonzalez-Salvador et al. 2000).

To conclude, although challenging behavior influences negatively many life domains, there is scarce data on the quality of life of persons with intellectual disabilities and challenging behaviors. Literature implies that challenging behavior is connected with personal functioning in daily life and that functioning relates to quality of life. However, additional data are required in order to establish a theoretical model. This study aims to examine three hypotheses:

H1: Challenging behavior will be negatively correlated with quality of life.

H2: Challenging behavior will be positively correlated with difficulties in functioning.

H3: Difficulties in functioning will be negatively correlated with quality of life.

These hypotheses will be tested using data from intellectually disabled individuals exhibiting challenging behavior and living in a private institution in Israel.

Method

Sample

An opportunity sample (based on convenience) of 53 people with intellectual disabilities and challenging behavior was recruited from one of the largest private institutions for people with intellectual disabilities in Israel. All the participants were Jewish Israelis. It is noteworthy that in 2011, an International Committee of Experts headed by Prof. Arie Rimmerman presented its report on integrated community living for people with ID in Israel (Blanck et al. 2011). The Committee recommended that Israel should plan and execute, over a period of 10 years, a transition plan for moving from institutional care facilities to community-based services. As a result, the Israeli Ministry of Social Affairs and Social Services presented a new policy directed at transferring residents of institutional residences to apartments in the community.

According to the Israeli Welfare Law (Treatment of Retarded Persons) 1969, diagnosis of intellectual impairment can only be established by a statutory diagnosis committee (Knesset Law Book 1969). Persons who are believed to have intellectual impairment are referred to one of the 10 diagnosis centers which perform various tests (i.e. Wechsler Intelligence Scale) whose results are summarized in a written report submitted to the diagnosis committee. The committee is comprised of the following five professionals appointed by the minister of Social Affairs and Social Services: A welfare officer, a psychologist, an educator/teacher, a physician, and a psychiatrist. The committee determines whether the tested individuals have intellectual impairment, the severity of the intellectual impairment, and possibilities of care (Nissim and Ben Simhon 2013). The participants in this study were diagnosed by a diagnosis committee with intellectual disabilities and challenging behavior with no additional diagnoses or comorbidities. Fifty-three individuals expressed their interest to participate in the study.

More than one half (58%) of the participants were men. Participants’ ages ranged from 20 to 64 years old, with a mean age of 40.2 years old (SD = 11.9). The largest group of participants (42%) was diagnosed with mild intellectual disabilities, followed by moderate intellectual disabilities (26%), mild to moderate intellectual disabilities (17%), and moderate to severe intellectual disabilities (13%).

Measurements

Challenging behavior scale

The Challenging Behavior Scale (CBS; Moniz-Cook et al. 2001) is a 25-item closed-ended questionnaire for service providers. The CBS was originally designed to measure challenging behavior among older people with dementia in nursing homes. The CBS was chosen because it covers both global and specific behaviors in residents with challenging behavior such as lack of occupation, agitation, aggression, eating, and sleep problems. In addition, this scale is a valid and reliable measure commonly used to measure challenging behavior in residential care settings (Moniz-Cook et al. 2001). For the purpose of this study, the CBS was translated into Hebrew and back to English by professional social science translators.

The CBS comprises 25 behaviors. The respondent is first asked to indicate whether the resident in question has displayed the given behaviors over the past eight weeks. Second, for each displayed behavior, the respondent is asked to indicate the frequency of the behavior on a scale from 1 to 4 (from less than once a month to daily) as well as the severity of the behavior, on a scale from 1 to 4 (from easily managed to extremely difficult to manage). The total score, that is, the total ‘level of challenge’ is the sum of the scores on the frequency and severity items and ranges from 0–400; the higher the score, the more challenging the behavior. The CBS was completed by a key staff member who knew the participant well and took approximately 10–15 min to complete.

World health organization disability assessment schedule 2.0

Functioning difficulties were assessed with the World health organization disability assessment schedule 2.0 (WHODAS-II; WHO, 2010). WHODAS-II is based on the International Classification of Functioning, Disability and Health, which systematically organizes the consequences of disease into three dimensions: body functions and structure, activities, and participation (Chwastiak and Von Korff 2003). WHODAS-II covers all types of disabilities (e.g. physical, mental, sensory) for various countries, languages and contexts, making it useful for cross-cultural comparisons. WHODAS-II includes four alternative versions of 89, 36, 12, and 6 items covering different ranges of impairment (Dubois and Trani 2009). In this study, the 12-item version was used. WHODAS-II consists of a set of items in which difficulty in quotidian functions is assessed over the previous 30 days. The difficulty is rated on five-point Likert scales that range from ‘no difficulty’ to ‘extreme difficulty or cannot do.’ In a validation study of 904 participants across 10 different conditions, the WHODAS-II schedule has been shown to have good reliability (Pösl et al. 2007). The WHODAS-II was chosen because it has been developed with the clear ICF bio-psycho-social conceptual model, it has satisfying psychometric properties, and it is easy to use. For the purpose of this study, the WHODAS-II was translated into Hebrew and back to English by professional social science translators. The WHODAS-II was completed by a key staff member who knew the participant well and took approximately five minutes to complete.

Personal well-being index

There are several quality of life measures for people with intellectual disabilities, but no universally accepted instrument exists for assessing the quality of life of people with intellectual disabilities who exhibit challenging behavior (Townsend‐White et al. 2012). The present study adopts the integrative approach that indicates that the quality of life consists of both objective and subjective elements (Cummins 2005) and uses the personal well-being index (PWI), which has been used successfully to measure the subjective well-being of people with intellectual disabilities (Cummins 1995; McGillivray et al. 2009).

The PWI scale contains seven items assessing satisfaction, each one corresponding to an area of quality of life: standard of living, health, achievement in life, relationships, safety, community connectedness, and future security. Scores in these areas are used to determine the answer to the first question: ‘How satisfied are you with your life as a whole?’ (International Wellbeing Group 2013) and provide insights into the various aspects that shape subjective well-being (Cummins 1996). Answers are reported on an 11-point Likert-type scale with anchor points of ‘completely satisfied’ (10), ‘neutral’ (5), and ‘completely dissatisfied’ (0) (McGillivray et al. 2009).

Raw scores were converted into standard 0–100 scale according to the PWI manual (intellectual disability version) (Cummins and Lau 2005a). The item ‘satisfaction with life as a whole’ is not a component of the PWI, which is analyzed as a separate variable (Yiengprugsawan et al. 2010). For Western populations, the normative range has been found to be 70–80 points on a 0–100 scale with a mean of 75, as in Australia (Cummins et al. 2003). PWI has demonstrated good psychometric performance in terms of its reliability, validity, and sensitivity (Yiengprugsawan et al. 2010); a correlation of .78 with the Satisfaction with life scale was reported (Diener et al. 1985). A variety of studies have reported a good Cronbach’s α coefficient (Cummins and Lau 2005b).

The intellectual disability version of the PWI was completed by the participants. The pretesting protocol and contents of the PWI were administered according to the test manual (Cummins and Lau 2005a). For participants unable to comprehend the standard 11-point scale, a set of reduced-choice format scales were provided. Those five-point, three-point, and two-point scales use drawings of faces from very happy to very sad.

Personal data

The institution’s social worker provided information about the gender, age, and the severity of intellectual impairment of the participants. The severity of intellectual impairment was determined by a diagnosis committee.

Data collection

The study was approved by the institutional review board of the University of Haifa in Israel. After receiving signed assent from the sampled individuals and informed consents from their legal guardians, structured interviews with 53 key staff members were conducted over a two-month period. All sampled individuals agreed to participate in the study.

Statistical analysis

To test the three hypotheses regarding the correlations between the research variables (e.g. challenging behavior, difficulties in functioning, and quality of life), Pearson’s r was employed.

Furthermore, the differences between participants according to their personal characteristics in regard to the research variables were also tested. An independent sample t-test was conducted to find whether any significant difference existed between men and women and between two groups of participants that was divided by the median values of age and ID severity.

Results

The internal consistency was measured by the Cronbach’s α, which is considered to be acceptable when it is equal or superior to 0.7 (Cronbach and Warrington 1951). The internal consistency of the CBS in this study was 0.80. The mean CBS score was 74.2 (SD = 45.5), that is, closer to the lower end of the CBS scale. The participants in this study exhibit between 1 and 18 different challenging behaviors (Mo = 12). The most prevalent challenging behaviors displayed by the participants in this study were verbal aggression (73%), shouting (68%), and demanding attention (66%), while the least common challenging behaviors were stripping (9%), inappropriate urinating (13%), and fecal smearing (15%).

For the WHODAS-II, the internal consistency (Cronbach’s )α was 0.87 and scores ranged from 13 to 51, with a mean score of 27.28 (SD = 11.15). As stated earlier, Cummins et al. (2003) reported 70–80 points to be the normative range of the scale, with a mean score of 75 points. Finally, in the present study, the mean PWI score was 67.13 (SD = 19.27) with a Cronbach’s α coefficient of 0.64, which is considered as demonstrating moderate internal consistency (Cronbach and Warrington 1951).

Pearson’s r was used to test three hypotheses: (1) challenging behavior will be negatively correlated to quality of life, (2) challenging behavior will be positively related to difficulties in functioning, and (3) difficulties in functioning will be negatively correlated with quality of life. Table 1 presents Pearson correlation matrix.

Table 1. Pearson’s correlations.

    1 2 3 4 5
1 Challenging behavior 1 .35* −.70 −.06 −.16
2 Difficulties in functioning   1 −.28* .18 .24
3 Quality of life     1 −.26 −.04
4 Age       1 −.13
5 Intellectual disability severity         1
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*

P < .05.

Hypothesis 1 was not confirmed. However, the results indicate that the second hypothesis was confirmed. It was established that a significant, moderate, and positive relationship exists between challenging behavior and difficulties in functioning. When we control the severity of intellectual disability on the relationship between challenging behavior and difficulties in functioning, the following partial correlation was found, r(50) = .40, P < .05.

The third hypothesis was also confirmed; a weak but significant negative correlation was found between difficulties in functioning and quality of life. Participants who had greater difficulty functioning tended to exhibit lower levels of quality of life. When we control the severity of intellectual disability on this relationship, partial correlation remains the same.

The differences between participants according to their personal characteristics with respect to the research variables (e.g. challenging behavior, difficulties in functioning, and quality of life) were also tested. An independent sample t-test found no significant effect of gender, age, and ID severity on challenging behavior, difficulties in functioning and quality of life (see Table 2).

Table 2. Independent sample t-test of personal data and research variables.

  Men (N = 31) Women (N = 22)  
M SD M SD t
Challenging behavior 66.84 49.04 84.68 38.70 –1.48 n.s.
Difficulties in functioning 25.13 9.81 30.32 12.40 –1.70 n.s.
Quality of life 71.84 13.45 60.50 24.13 2.19 n.s.
  Age ≤ 38 (N = 27) Age > 38 (N = 26)  
  M SD M SD t
Challenging behavior 75.67 47.80 72.77 43.90 0.23 n.s.
Difficulties in functioning 26.67 10.50 27.92 11.96 –0.41 n.s.
Quality of life 69.63 18.76 64.53 19.82 0.96 n.s.
  Mild-moderate ID (N = 31) Moderate-severe ID (N = 22)  
  M SD M SD t
Challenging behavior 82.35 45.30 62.82 44.30 1.57 n.s.
Difficulties in functioning 25.19 10.88 30.23 11.09 –1.65 n.s.
Quality of life 67.60 16.01 66.46 23.52 0.21 n.s.
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*

Participants were subdivided according to median values of age and ID severity (38 years old and mild to moderate ID).

Discussion

There are scarce data on the quality of life of persons with intellectual disabilities and challenging behaviors. Challenging behavior is perceived as one that presents a challenge for policy-makers and service providers to provide appropriate and effective supports (Banks et al. 2007). Therefore, there is a growing interest in studying its relations with different aspects of the individual’s life. The present study examined three hypotheses with respect to challenging behavior, difficulties in functioning, and quality of life. First, it was expected that high levels of challenging behavior would be related to lower quality of life, but no support for this supposition was found. However, findings did indicate that high levels of challenging behavior are associated with greater difficulties in functioning in institutionalized adults with intellectual disabilities. Finally, it was established that difficulties in functioning were connected to reductions in quality of life.

It has been argued that challenging behavior has a significant impact on people’s lives and therefore reduces their quality of life (Banks et al. 2007; Gerber et al. 2008; Hastings 2002; Holden and Gitlesen 2006; Totsika et al. 2010), but only a few empirical studies have focused on the quality of life of people with both intellectual disabilities and challenging behavior (Grey and Hastings 2005; Morisse et al. 2013). In the present study, the correlation between challenging behavior and quality of life was not supported. One explanation for the lack of such an association might be the influence of quality of life on promoting stability and balance (Brickman and Campbell 1971; Headey and Wearing 1992; Suh et al. 1996). Studies have shown that challenging behavior is a chronic condition (Chadwick et al. 2005; Murphy et al. 2005; Totsika et al. 2008), so it is not unreasonable to assume that the participants’ challenging behavior influenced the baseline of their quality of life. Nota et al. (2006) argued that individuals tend to adapt to life’s conditions, even to negative experiences. Despite challenging behavior’s negative effect on social skills (Kearney and Healy 2011) and social inclusion (Murphy 2009), it is possible that the participants’ quality of life was initially poor but remained stable. Furthermore, it should be noted that no agreed-upon definition and measurement for quality of life exists (International Wellbeing Group 2013). In this study, the PWI was used to assess quality of life, but it is possible that a more detailed measurement is needed to explore the influence of challenging behavior on quality of life.

The second hypothesis which stated that challenging behavior would be positively correlated with difficulties in functioning was confirmed. It has been argued that challenging behavior can seriously damage both a person’s health and functioning (Emerson and Einfeld 2011). Moreover, Emerson et al. (2001) noted that people with intellectual disabilities and challenging behavior need more help eating, dressing, and walking, and that these individuals are more dependent on others. The study’s findings accord with those of Irazábal et al. (2012) that people with intellectual disabilities and challenging behavior exhibit higher levels of disability than people with just intellectual disabilities. McGeown et al. (2013) also discussed the effect of challenging behavior on dysfunction in many areas of life and found that challenging behavior is a strong predictor of poor functioning.

The third hypothesis, which claimed that difficulties in functioning would be negatively correlated with quality of life, was also confirmed. The finding is compatible with the Gonzalez-Salvador et al. (2000) study that found physical dependency to be associated with a poor quality of life. The concept of quality of life consists of several domains, including physical well-being (Schalock 2004), which refers to functioning and daily activities such as the ability to care for oneself and mobility. The correlation between difficulties in functioning and quality of life found here reinforces this concept of quality of life.

In light of these findings, it is reasonable to believe that interventions that empower personal functioning are likely to promote a higher quality of life for people with intellectual disabilities. Support and assistance in daily activities for those with intellectual disabilities and challenging behavior should contribute to a better quality of life. Although challenging behavior did not correlate with quality of life, it was found to be correlated significantly with functioning. However, it is not certain that challenging behavior causes an increase in difficulties in functioning rather than the other way around. Greater difficulties may cause negative feelings of frustration and irritability that manifest themselves through challenging behavior and also reduce one’s quality of life.

Unlike previous reports on the positive relationship between the severity of intellectual disability and challenging behavior (Emerson and Bromley 1995; Emerson et al. 2001), no correlation between these variables was found in this study.

The findings in this study should be interpreted with caution. The study has several limitations that open up avenues for future research. First, only 53 participants with challenging behavior were able to respond to the research measurements. The small sample and limited variance in challenging behavior influence the data analysis. A second limitation refers to the generalizability of the data; despite the fact that the study was conducted in a large facility typical of its type, we had only one such institution. A third limitation refers to the use of the CBS. Although it was developed to measure challenging behavior in residential care settings, the CBS was not designed specifically for individuals with intellectual disabilities.

Future research should address the relationships found in this study and investigates them further. It is important to determine whether difficulties in functioning affect quality of life directly or indirectly. A mediation model is proposed, in which challenging behavior is suggested to mediate the relationship between difficulties in functioning and quality of life. Another direction for an indirect correlation might involve various social factors, such as social participation, social capital or inclusion, or the person’s performance in other domains of life such as employment and leisure. It is also important to establish whether challenging behavior causes increased difficulties in functioning or vice versa and to explore this correlation among other relevant populations, such as elderly people with dementia and those with autism. Thus, despite its limitations, the study provides some initial insights into the relationships between challenging behavior, functioning, and quality of life, and offers practitioners some ideas about how to improve the last factor for intellectually disabled people who exhibit challenging behavior.

Footnotes

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