Synonyms

ABC; ABC-C; ABC-R; Aberrant Behavior Checklist – community; Aberrant Behavior Checklist – residential

Description

The Aberrant Behavior Checklist (ABC) is an informant rating instrument that was empirically derived by principal component analysis (Aman et al. 1985a). It contains 58 items that resolve onto five subscales. The subscales and the respective number of items are as follows: (a) Irritability (15 items), (b) Social Withdrawal (16 items), (c) Stereotypic Behavior (7 items), (d) Hyperactivity/Noncompliance (16 items), and (e) Inappropriate Speech (4 items). A total score for this instrument was not psychometrically derived and is not valid. The ABC was designed to be completed by any adult who knows the client well. This could be a parent, teacher, workshop supervisor, case worker, or informants in other roles. Depending upon reading ability, completion time varies, but most raters complete the ABC in 10–15 min the first time. Thereafter, rating times usually decline.

A revised version of the ABC was published in 2017, along with a detailed manual (Aman and Singh 2017) and freely available annotated bibliography (https://psychmed.osu.edu/index.php/instrument-resources). With respect to the actual content of the scale, although the wording of a handful of items was generalized (e.g., references to “the ward” and “patients” have been altered), the meaning of all items remains the same as in the original version. Subscale titles similarly underwent slight changes; “Irritability, Agitation, Crying” is now entitled Irritability and “Lethargy, Social Withdrawal” is now Social Withdrawal. Finally, substantive changes to the face sheet were undertaken in an effort to create more usable data. More general terms for school and other settings were used to facilitate comparison, as such terms are variable over time and across geographic location. Rather than querying individual diagnoses, the face sheet now requests explanations and, where relevant, severity about various conditions that might impact behavior (e.g., sensory or physical impairments, developmental disabilities, medical diagnoses).

The remainder of the face page is unchanged from the previous version; the rater is asked to provide the client’s sex, date of birth, and the rater’s relationship to the client, and a listing of any medicines being used by the client. In the context of treatment studies, this information (other than the subject’s name and date) is often not collected.

Instructions for completing the ABC and its 58 items are found on the second page of the instrument. The period over which informants rate the client defaults to 4 weeks. However, depending on the clinical or research needs, this period can be increased or decreased. The instructions ask the informant to rate the client on a scale ranging from 0 (not at all a problem) to 3 (the problem is severe in degree). Further, the instructions ask raters to take relative frequency into account, such that if a given behavior occurs more than the client’s reference group (e.g., other children of the same age and sex), scores greater than or equal to 1 are warranted. The instructions also encourage informants to consider observations and reports of other responsible adults who know the client well when making their ratings. Finally, the instructions indicate that behaviors which interfere with the client’s development, functioning, and/or social relationships should be rated as a problem, even if these behaviors do not interfere with other people around the client. The 58 behavior items consume about 1½ pages of the form.

Initially, the ABC was developed primarily as a measure of treatment effects, especially as an outcome measure for pharmacological intervention. With time, the use of the ABC has expanded, and it has been employed, fairly frequently, for the following applications: (a) to examine psychometric characteristics of other instruments and/or the ABC itself, (b) to study the behavioral phenotypes of individuals with genetic and metabolic conditions, (c) to examine the effects of different environmental variables (e.g., size of housing arrangements) on behavior, (d) to characterize the composition of subjects within studies and/or programs, (e) to assess the effects of sleep disruption on client behavior, (f) to characterize individuals with different types of psychiatric disorders, and (g) to evaluate quality of life.

There are at least 35 languages into which it has been translated, including the following: Afrikaans, Arabic, Chinese, Czech, Danish, Dutch, Filipino, Finnish, French (Belgian, Canadian, and European), German, Greek, Hebrew, Hungarian, Indonesian, Italian, Japanese, Korean, Lithuanian, Norwegian, Persian (Farsi), Polish, Portuguese, Romanian, Russian, Serbian, Slovak, Slovenian, Spanish (Colombian, Mexican, Spanish, and USA), Swedish, Thai, Turkish, Telugu (regional language of Andhra Pradesh, India), Ukrainian, Urdu, Vietnamese, and Zulu. At the time of this writing, the following language translations were revised for compatibility with the 2017 ABC revision: Afrikaans, Arabic, Canadian French, European French, Chinese (Traditional), English (USA), Filipino, Hebrew, Kannada, Korean, Norwegian, Polish, Portuguese, Russian, Spanish (Spain and USA), and Urdu.

In 2017, a single manual for the community and residential versions of the ABC replaced previous separate versions (Aman and Singh 1986, 1994). This new manual addresses an array of subjects not covered in the original manuals, including sections on giving instructions to raters, practices to avoid, and using the ABC for characterizing change at the individual and group levels. The ABC-Second Edition Community/Residential Manual (Aman and Singh 2017) gives the history of the ABC’s development and elaborates upon the meanings of all 58 items. Average subscale scores and standard deviations (normative data) are provided for adults, sourced from developmental centers in the United States and New Zealand. Normative data for teacher ratings of children and adolescents in special educational classes are provided in the following formats: (a) T-scores and percentiles by sex and age, (b) T-scores with all ages and sexes combined, and (c) means and standard deviations broken out by age and sex, as well as collapsed across all ages. The group home norms are presented in the following ways: (a) T-scores and percentiles by age (10-year groupings) and functional levels (mild, moderate, severe, and profound intellectual disability); (b) T-scores and percentiles collapsed across functional level, summarized for age alone and for sex alone; and (c) means and standard deviations broken out by combinations of functional level and age and summarized by sex alone. Normative data for parent ratings of children and adolescents with intellectual disability are provided as means and standard deviations broken out by age and sex. The manual is also a comprehensive source for information on studies of the psychometric properties of the ABC, including internal consistency, interrater reliability, test-retest reliability, criterion group validity, concurrent and discriminant validity, and correspondence of ratings with direct observation scores. We summarize some of the information contained in the manual herein. There have been about 450 scientific studies conducted with the ABC, providing a rich literature against which new work can be compared.

Historical Background

The development of the ABC grew out of a practical need for an instrument to assess treatment effects in people with DD (e.g., Singh and Aman 1981). Development of the ABC was closely modeled on the Behavior Problem Checklist of Quay and Peterson (Quay 1977) and the enormously popular Conners’ Parent and Teacher Rating Scales (Conners 1969, 1970). The initial form of the ABC contained 125 items, developed after a review of residential center case records, a survey of existing instruments, and consultation with direct care staff regarding content and wording. A pilot study obtained ratings from caregivers of 418 adolescents and adults with DDs. Items endorsed for fewer than 10% of subjects were dropped, and a principal factoring method was conducted with oblique rotation, leaving 76 items. The intermediate 76-item scale was then used to rate a new group of 509 adolescents and adults.

The data from both samples were analyzed independently by a principal factoring method followed by oblique rotation. A five-factor solution seemed most interpretable in both analyses. Items that failed to load on the same respective factors across analyses were deleted, leaving 58 items in the ultimate ABC.

Two important subsequent changes took place more or less simultaneously. First, the original ABC contained some language that was distinctly institutional in flavor (e.g., “excessively active on the ward”). This language was modified in the early 1990s (e.g., “excessively active at home, school, work, or elsewhere”) to form what was then called the ABC-community. At about the same time, investigators assessed the ABC in child samples and found that the original factor structure was maintained for children and adolescents (e.g., Marshburn and Aman 1992; Brown et al. 2002). The earlier version of the ABC was dubbed the ABC-Residential to distinguish it from the newer ABC-Community. Thus, at this stage, there were residential and community versions available, and the Community version’s structure was validated for children, adolescents, and adults.

With time, the ABC came to be used more and more in pharmacological research involving people with intellectual disability and/or autism spectrum disorders (ASDs). Other uses are described under Clinical Uses, below. Much of the published research with the ABC can be accessed through the Annotated Bibliography on the ABC (Aman 2015; available at http://psychmed.osu.edu/resources.htm). One important development was the adoption of the ABC’s Irritability subscale as the primary outcome measure by the Research Units on Pediatric Psychopharmacology (RUPP et al. 2002, 2005), a network of experienced psychopharmacology laboratories funded by the US National Institute of Mental Health. In two studies, the RUPP network showed that risperidone was highly effective in reducing agitated and irritable behavior for children and adolescents with autistic disorder chosen for high initial scores on the Irritability subscale. Using data from these pivotal investigations and from another clinical trial, Johnson & Johnson Pharmaceuticals obtained a clinical indication from the United States Food and Drug Administration for the use of risperidone in children and adolescents with autism and significant agitation and irritability. At that point, it was the only medication approved by the FDA for treating patients with autism. Subsequently, Bristol-Myers Squibb Company launched two pivotal clinical trials of aripiprazole in children and adolescents with autism and agitated/irritable behavior, again with the ABC Irritability subscale as the primary outcome measure. Bristol-Myers Squibb was also able to obtain a clinical indication for its product.

These developments have made the ABC a popular choice as an outcome measure for the pharmaceutical industry when targeting behavior problems in patients with DD. However, it is important to realize that individual academic investigators were using the ABC long before it was adopted as an outcome by industry. In 2015, Bearss et al. published an experiment showing that psychosocial training, administered by parents of children with autism spectrum disorder, was highly effective in reducing disruptive behavior in the children as assessed by parent ratings on the Irritability subscale of the ABC. It seems probable that the ABC will be used widely in future to assess the impact of psychosocial treatments in children with DDs. As noted under Clinical Uses, below, the ABC has been used for approximately 450 pharmacological and nonpharmacological purposes over the last 30+ years.

Psychometric Data

There is a wealth of psychometric data on the ABC.

Construct Validity. There have been several independent factor analyses with the ABC which have supported its construct validity (a) across versions of the ABC, (b) across settings (large residential vs. small, within the community), and (c) across age groups. Most of these studies have been referenced and summarized in the Annotated Bibliography on the ABC (Aman 2015; freely available at http://psychmed.osu.edu/resources.htm), and they are summarized in Table 1.

Table 1 Studies of the construct validity of the ABC
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As shown in Table 1, all studies of construct validity essentially verify the ABC factor structure as described in the original report (Aman et al. 1985a). Two studies failed to find the Inappropriate Speech factor in children, possibly because of a lack of participants with ASDs; it is worth noting that a very large study (n = 1,893) of children with ASD demonstrated excellent support for the original factor structure (Kaat et al. 2014). One study (Brinkley et al. 2007) found significant changes to the Irritability factor when subjects with high rates of self-injury (SIB) were included, but the factor structure was confirmed when these subjects were excluded.

Other Forms of Validity. The original ABC development study included several validity comparisons (Aman et al. 1985b). Concurrent validity was established through moderate correlations with existing standardized scales (e.g., the AAMD Adaptive Behavior Scale), and comparisons of criterion groups yielded predictable patterns of difference (e.g., individuals who attended formal training activities received lower subscale scores than those who did not). Further, direct observations of the individuals in their residences were well-correlated with ABC scores. Finally, compared to unmedicated individuals, those prescribed psychotropic medications had significantly higher ABC scores on all domains except Repetitive Speech.

Subsequently, numerous studies have demonstrated the validity of the ABC, and the manual cites about 35 studies addressing validity. Examples of this include concurrent validity between the ABC and other formal instruments, including (a) the Psychopathology Instrument for Mentally Retarded Adults, (b) the Nisonger Child Behavior Rating Form, (c) Conners’ Teacher Rating Scale, (d) Diagnostic Assessment for the Severely Handicapped-II, (e) Reiss Screen for Maladaptive Behavior, (f) Stereotyped Behavior Scale, (g) Teacher Report Form, and (h) The ADD-H Comprehensive Teacher’s Rating Scale.

Reliability Assessments. Many researchers, especially those who conducted factor analysis with the ABC, reported alpha coefficients – a measure of internal consistency. Generally, coefficient alpha ranged from the low 0.80s to the middle 0.90s, indicating a high level of consistency.

Interrater Reliability. Many of the studies that examined cross-informant reliability are summarized in Table 2. These generally fell into the low 0.50s to high 0.60s range, which is quite adequate for both research and clinical practice. Using criteria established by Cicchetti and Sparrow (1981), these reliabilities fall into the fair to good ranges.

Table 2 Summary of interrater reliability studies with the ABC
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Test-Retest Reliability. Several studies that examined test-retest reliability are summarized in Table 3. Median reliability ranged from the mid-0.60s to highs in the 0.90s. In general, test-retest reliably was quite high, falling within ranges characterized by Cicchetti and Sparrow (1981) as good to excellent.

Table 3 Summary of test-retest reliability studies with the ABC
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Clinical Uses

As noted, the ABC was developed as an outcome measure for pharmacological trials in people with developmental disabilities, and it has been used heavily for this purpose (see Annotated Bibliography, Aman 2015). However, use of the scale is not confined to research. The ABC can be used, in combination with other data-based approaches, to monitor the effects of routine clinical care in people with intellectual disabilities and/or ASD.

Its early use was primarily among individuals with intellectual disabilities alone, but in recent years it has been used a great deal to assess treatment outcomes in individuals with ASD. This is supported by the available data; one large study (n = 1,893) produced very strong evidence for the factor validity of the ABC when used in children and adolescents with ASD. However, it is worth noting that although several subscales assess features of ASDs (e.g., Social Withdrawal, Stereotypic Behavior, Inappropriate Speech), the ABC was not intended to be a measure of overall autism severity.

As research on specific genetic conditions becomes more common, investigators have attempted to identify syndrome-specific factor structures rather than employing the validated existing structure. This practice is likely to yield unstable results, and researchers are cautioned against this practice (Aman and Singh 2017). Recently, Aman et al. (2020) analyzed extensive data from participants with fragile X syndrome and concluded that the classical scoring algorithm, as presented in the ABC Manual, is the optimal way of presenting ABC results.

Periodically, the ABC had been used to assess the effects of behavior intervention, both in formal research (Aman et al. 2009; Bearss et al. 2015) and in everyday care. Obviously, it is important to document the efficacy of such treatment. The ABC has been used to select participants for various forms of research intervention, especially pharmacological investigations. It may serve a similar role in routine clinical care to identify individuals who warrant preventive care and/or active intervention. As noted earlier, the ABC has been used to monitor behavior in those experiencing transition, such as moving from one living environment to another. It has also been used to assess co-occurring behavioral issues in people with genetic or metabolic syndromes, and this is another likely area of clinical application.

The ABC has primarily been used to assess school-aged children, adolescents, and adults through late middle age. The largest psychometric study of the ABC in preschoolers (n = 556, Kaat et al. 2014) produced convincing evidence that it is valid for use in this age group, at least for those with ASD. Although there have been a few studies among elderly people, its utility here has yet to be properly and thoroughly established.

To conclude, the ABC is used to measure and document changes in behavior. These can be changes associated with pharmacological or behavioral intervention or those instigated by environmental alterations. The ABC appears well-suited to assessing a range of ages extending from school-age through late middle age. It has been useful for characterizing the behavior of people with ASD, ID, and a multitude of developmental disability-specific syndromes.