DM-ID: Diagnostic Manual - Intellectual Disability

--Excerpt from Chapter 20, Obsessive-Compulsive Disorder, by Robert King, M.D., FRCP (C), Chrissoula Stavrakaki, M.D., Ph.D., and Angela Gedye, Ph.D.

Issues Related to Diagnosis in Persons with ID

1. Compulsions that require abstract thinking are common in OCD in the general population, but can be rare or absent in OCD in individuals with ID. Clinicians familiar with OCD in people of average intelligence may believe that OCD is absent if a person with ID does not engage in “classic” compulsions. Compulsions that require counting skills or abstract concepts such as contamination or germs (compulsive hand washing) or safety (repetitive checking of door locks or stove dials) do not occur in those individuals with ID who are unable to think abstractly or to count.

2. Limited language ability in individuals with ID reduces the likelihood of self-report of obsessive thoughts, clinical interviews eliciting obsessive thoughts or images, or clinical observations of obsessive speech patterns.

3. Limited language ability in individuals with ID often prevents clinicians from being able to directly interview the person or have the person complete assessment questionnaires, scales, or inventories. This greatly increases the need to conduct structured interviews with knowledgeable informants and to use instruments designed for this population.

4. Additional sensory impairments (such as blindness or deafness) in some individuals with ID further restrict the range of obsessive-compulsive phenomena. An individual with ID who has OCD and blindness will not be visually stimulated to enact ordering, cleaning, or deviant grooming compulsions, but may have compulsions mainly involving touch (e.g., repetitive tapping or compulsive daily ripping of clothing). An individual with ID who has OCD and deafness will not talk obsessively or orally asking questions endlessly, but may repeat hand signs obsessively and present with a variety of other observable compulsive actions.

5. Not all repetitive behaviors in individuals with ID can be demarcated as obsessive-compulsive phenomena (Clarke et al., 2002; Gedye, 1996; King, Fay, Turcotte, Wheildon, & Preston, 2002; McBride & Panksepp, 1995; Vitiello et al., 1989). Repetitive behaviors with physiologically rewarding properties should not be used to make the diagnosis, namely, masturbation, stealing, hyperventilation (aerophagia), overeating, overdrinking (polydipsia), smoking, humming, and pacing. Self-injurious movements may be present in persons with OCD (Bodfish, Symons, Parker, & Lewis, 2000; Hyman, Oliver, & Hall, 2002), but “the fact that there is an association &ldots; is not sufficient evidence to support the hypothesis that SIB is an involuntary, compulsive behavior” (Hyman et al. 2002, p. 151).

6. Anxiety does not occur in all OCD patients in the general population (e.g., Barnhill, 1999; Insel, 1985) and is even less commonly reported or observed in OCD in individuals with ID (Deb, Matthews, Holt, & Bouras, 2001), especially those with Severe or Profound ID. Moreover, “young children may lack obsessional anxiety” (Dar & Greist, 1992, p. 891). Anxiety is not a diagnostic requirement for OCD (Strength of evidence: V, III).

7. People of average intelligence with OCD may try to reduce their compulsions or hide them from society, fearing loss of a highly paid career or marriage. Individuals with ID and OCD may lack awareness of societal disapproval and hence not try to reduce their compulsive behaviors.

8. Among people with ID, aggression may be the presenting concern, and caregivers may not mention “compulsions” or “obsessions.” The clinician needs to ask if the aggressive actions are directed toward “removing an obstacle” that impedes the individual with ID from completing a ritual or fixed way of doing something. Does hitting and kicking stop when the staff who has been intervening stop preventing the individual with ID from engaging in their compulsive activity? The clinician needs to collect information about other behaviors as well (e.g., the Compulsive Behavior Checklist for Clients with Mental Retardation [CBC], Gedye, 1992; 1996) because individuals with ID may have many benign rituals and fixations which are nonproblematic but collectively are consistent with the obsessive-compulsive spectrum. Furthermore, an individual with ID and OCD may engage in many types of compulsive activities, but only one type causes caregivers to intervene provoking an aggressive response by the individual. If clinicians do not know what questions to ask informants in order to elicit possible obsessive-compulsive behaviors, then the OCD may continue unrecognized and no connection be made between aggression and OCD activities.

Applications of Diagnostic Criteria to People with ID

1. Obsessional slowness occurs in people without ID (Rachman, 1974; Rasmussen & Eisen, 1990; Ratnasuriya, Marks, Forshaw, & Hymas, 1991; Sawle, Hymas, Lees, & Frackowiak, 1991) and among individuals with ID (Charlot, 2002; Clark, Sugrim, & Bolton, 1982; Pary, 1994; Vitiello et al., 1989). Obsessional slowness has been described in Down syndrome (Charlot, 2002; Charlot, Fox, & Friedlander, 2002; Pary, 1994). It is considered rare in OCD patients from the general population and may be rare among people with ID (Charlot, 2002) (Strength of evidence: III, V, IV).

2. In applying diagnostic criteria to individuals with ID, the risk of diagnostic false negatives—missing OCD when it is present—increases with the following:

· Failing to inquire about compulsions that are common in persons with ID or failing to inquire about the full range of possible compulsions. It is important to collect information from informants using a checklist or scale designed for detecting OCD symptoms in individuals with ID (see list below);

· Regarding the absence of compulsions that require abstract thinking like excessive hand washing and counting as ruling out OCD;

· Regarding a lack of anxiety as automatically ruling out OCD;

· Regarding the lack of inner discomfort or “egodystonic” response to obsessive-compulsive behaviors as automatically ruling out OCD; and

· Using a medication trial as a way to “rule out” a diagnosis of OCD.

The risk of diagnostic false positives—labelling someone with OCD when it does not apply—increases with the following:

· Using a medication trial as a way to “confirm” a diagnosis of OCD;

· Regarding collecting behavior in a person with no other compulsive activities as a hoarding compulsion; and

· Overlooking the relation between onset or worsening of OCD symptoms and the use of certain neuroleptics that can induce OCD symptoms in persons with no prior symptoms (Baker et al., 1992; Mottard, & de La Sablonnière, 1999; Patel & Tandon, 1993; Patil, 1992; Remington & Adams, 1994) (Strength of evidence: IV, V).

The following instruments have been designed specifically for assessment of individuals with ID. The Compulsive Behavior Checklist for Clients with Mental Retardation (CBC, Gedye, 1992; 1996) is a guide for collecting information to aid in determining if OCD criteria have been met. This instrument has been analyzed psychometrically by independent researchers. It has good interrater reliability (84.8%), test-retest stability (83.3%), and validity (91.4%) (Bodfish et al., 1995). The factor structure of its items was found to be very robust (Feurer et al., 1998). The Obsessive Speech Checklist (OSC, Gedye, 1998) is a guide for collecting information on obsessive speech patterns in individuals with ID who are verbal and not functioning in the range of profound ID. No independent psychometric analyses have yet been reported. The OCD Severity Scale (Vitiello et al., 1989) is a scale for rating severity of OCD symptoms in individuals with ID. It is valuable for evaluating changes in OCD symptoms after treatment, but has limited value as a screen in making the diagnosis. No independent psychometric analyses have yet been reported (Strength of evidence: V, III, IV).

Research Applying to People with ID

A computerized search of the literature in English from 1985 until present day was performed using as key words: mental retardation, developmental disabilities, Obsessive Compulsive Disorder, assessment, treatment, diagnosis, pharmacology, obsessions, compulsions, repetitive behaviors, prevalence, etiology, genetics, and comorbid disorders. The following databases were examined: Medline, MD Consult, Medscape, Psychinfo, Embase, CINAHL, and the Cochrane Database of Systematic Reviews. Review of bibliographies and reference lists provided additional relevant articles. The Cochrane Convention method criteria were used to evaluate the evidence found within the literature.

Practice parameters reflect the difficulty in eliciting DSM-IV-TR defined obsessions in individuals without verbal skills who have ID (Szymanski & King, 1999). These difficulties were acknowledged with the introduction of the DSM-III (APA, 1980), with an emphasis on behavioral and phenomenologically-based criteria. Less emphasis was placed on subjective psychological symptoms and inner conflicts requiring a verbal exchange between the clinician and patient. This shift was a major development in facilitating the diagnosis of psychiatric disorders in individuals with limited cognitive or language skills. Research on the presentation of psychiatric disorders in children has also facilitated this process, prompting allowances for developmental influences on symptom expression in individuals with ID.

Concern has been expressed regarding wide discrepancies in reported prevalence rates of psychopathology in individuals with ID. These parameters have suggested that these discrepancies are due to variations in methodology, diagnostic definitions, and population sampling procedures. A number of factors limiting the establishment of a valid DSM-IV-TR Axis I diagnosis in individuals with ID were cited. These included the experience and training of the clinician, the patient’s limited communication skills, a lack of reliable history, and a lack of sufficient time for a diagnostic assessment. With respect to the diagnosis of OCD, it was noted that “differentiating between self-stimulatory stereotypic behavior and compulsions can be difficult in non-verbal individuals who cannot describe obsessional thoughts or identify compulsions as obsessions” (Szymanski & King, 1999, p. 20S) (Strength of evidence: V).

The limitations of the DSM-IV and ICD criteria with respect to their applicability to individuals with ID have been further discussed in Rush and Frances (2000). In establishing an expert consensus panel, forty-eight psychosocial experts and forty-five medication experts in the field concluded that “in the context of more severe MR, the experts did not believe that it is possible routinely and reliably to make any of the specific DSM-IV diagnoses (except for Autistic Disorder), and they have little enthusiasm for structured or unstructured interviews in this population” (Rush & Frances, 2000, p. 166). The necessity of focusing on behavioral symptoms as a target of treatment was cited when “a specific DSM-IV created diagnostic approach yields no more than a relatively non-specific diagnosis” (Rush & Frances, 2000, p. 166) (Strength of evidence: V).

The use of DSM-IV and ICD diagnostic criteria for people with ID has also been reviewed by Sturmey (1993). Studies he reviewed were based on clinical interviews, as well as case notes or structured checklists. Sturmey noted that (1) not a single study reviewed reported reliability of psychiatric diagnoses, and (2) all studies, other than a single study, modified diagnostic criteria in some way. He noted that even seemingly minor changes in diagnostic criteria have been shown to lead to substantial changes in diagnosis. He was concerned that these studies could not be well replicated or compared given that these studies lacked explicitness as to how ICD-9 and DSM-IV criteria were modified. He concluded that in order to establish a valid psychiatric diagnosis in individuals with ID and mental health concerns, specific procedures and diagnostic algorithms would have to be developed and the integrity of these processes demonstrated. He also reviewed a number of behavioral checklists with an emphasis on the Psychopathology Inventory for Mentally Retarded Adults (PIMRA) and the Diagnostic Assessment for the Severely Handicapped (DASH), suggesting that items in these scales were explicitly related to DSM-III criteria and yielded sub-scales corresponding to DSM-III disorders. Acknowledging that these scales have good psychometric properties, he expressed concern that they failed to address information other than current behavior, thereby limiting their role in the diagnostic process (Strength of evidence: I).

In reviewing the epidemiology and prevalence of psychopathology in people with ID, Borthwick-Duffy (1994) noted that there was a wide range of reported prevalence rates of psychiatric disorders in people with mental retardation, ranging from less than 10% to greater than 80%. These discrepancies were attributed to (1) definitional and identification issues and (2) sampling issues. Again, a need for valid and reliable assessment of the conditions of both ID and the co-presence of mental disorders was stressed (Strength of evidence: IV).

King, DeAntonio, McCracken, Forness, and Ackerland (1994) presented a naturalistic study of 951 individuals with Severe to Profound ID referred for psychiatric assessment over a three-year period in a California developmental center. An attempt was made to use diagnoses based on DSM-III criteria. They acknowledged, however, that a rigid interpretation of DSM-III criteria might alter diagnostic accuracy, particularly in nonverbal individuals. In discussing the difficulties in establishing a diagnosis of OCD, they suggested that simple repetitive behaviors as opposed to compulsive behaviors that appear driven or an insistence on sameness that can accompany PDD should not be given a separate OCD spectrum diagnosis (Strength of evidence: IV).

The categorical and phenomenological approach of the DSM-IV has been criticized by Barnhill (1999) with respect to its applicability to individuals with ID. He suggested that the diagnosis of an Anxiety Disorder requires, in addition, a careful evaluation of the setting, set, and the behavioral repertoire of the individual. Setting is defined as clues to specific triggers, the level of complexity of the environment, demands for novelty, and requirements for behavioral adaptation. Set is defined as an individual’s temperament, the intensity of physiological arousal, an individual’s threshold for repetitive stereotypic behavior, and their genetic vulnerability to Anxiety Disorders. He also noted that it is often difficult in individuals with Severe to Profound ID to identify the intensity of symptoms and the degree of social impairment as is required by the DSM-IV. He suggested specific modifications to diagnostic criteria, including: (1) a description of physiological arousal, fear responses, reactions to novelty, and thresholds for repetitive and stereotypic behavior, (2) an observational approach reflecting the state of the individual and the level of reactivity, adaptivity, and proneness to repetitive behavior, and (3) more emphasis on observation of attachment behaviors, which would intensify in stressful situations in individuals with Severe to Profound ID, particularly in stressful situations which would be perceived as a loss or disruption. He noted the current statistical discrepancy between prevalence rates of Anxiety Disorders diagnosed in individuals with Mild versus Severe ID, despite high rates of language impairment, brain dysfunction, seizure disorder, and sensory impairments in the latter group. He concluded that this discrepancy reflected limitations of the current diagnostic system, rather than true prevalence rates (Strength of evidence: V).

Deb et al. (2001) have established best practice guidelines for the assessment and diagnosis of health problems in adults with ID. These guidelines list ICD-10 criteria for OCD. They include obsessions and compulsions recognized as originating in the subject’s mind. These are described as being repetitive, unpleasant, excessive, and non-reasonable. The subject is required to attempt to resist thinking about the obsessions or carrying out the compulsions. Expressing the obsession or carrying out the compulsion is deemed to be not pleasurable, although it is noted that it may bring temporary relief. Interference with social functioning or the development of stress is cited. These guidelines noted:

It may be difficult to elucidate the presence of obsessions in an individual with an intellectual disability. They may be unable to recognize it as coming from their own mind and resistance may not occur. Anxiety is not always a recognized feature&ldots;[Compulsive behavior needs] to be distinguished from stereotyped behavior and movement disorders caused by underlying brain damage (p. 710) (Strength of evidence: V).

Citing Vitiello et al. (1989), they concur that there should be an emphasis on behavioral, generally observable, components of the disorder, rather than observable states of behavior. Deb and associates (2001) note that in this context, Bodfish and Madison (1993) have proposed the term “compulsive behavior disorder”. (Strength of evidence: IV, V, III).

Adults with Mild to Moderate ID

The higher the level of intellectual performance, including complex speech development, the closer the clinical presentation of OCD adheres to the DSM-IV-TR criteria. The clinical presentation of OCD at the Mild degree of ID is similar to that within the general population (Jenike, Baer, & Minichiello, 1998; King, State, Shah, Davanzo, & Dykens, 1997; Stavrakaki & Mintsioulis, 1996). However in persons with Moderate ID, the clinical symptoms of OCD are dependant upon the degree of the disability itself as well as speech development. Lower functioning individuals within this range, especially if speech is absent or underdeveloped, present OCD as aberrant behaviors such as excessive repetitive behaviors that can be difficult, at times, to distinguish from stereotypies and SIB (Davidson et al., 1996; Khreim & Mikkelsen 1997; Prasher & Day 1995) (Strength of evidence: V, IV, III).

Major distinguishing factors at the Moderate range of ID are the apparent lack of exhibited anxiety, subjective resistance to these behaviors, and seeking of corrective remedies for these behaviors (McNally & Calamari, 1989) (Strength of evidence: V).

Adults with Severe or Profound ID

The absence of obsessions or compulsions which are very common, almost ‘classic,’ in OCD in individuals without ID, does not rule out OCD in individuals with ID. Obviously, people who are unable to think abstractly will not present with obsessions and compulsions that require abstract thinking. For example, obsessive thoughts of contamination fears that lead to frequent hand washing or safety-related doubts that lead to frequent checking of stove dials or door locks require abstract thinking. Compulsive hand washing is very common in OCD in individuals without ID (e.g., Insel, 1985; Khanna, Kaliaperumal, & Channabasavanna, 1990). However, many people in the Severe to Profound range of ID are dependent on caregivers to wash and bathe them, hence, they are incapable of independent hand washing. Moreover, most persons with Severe or Profound ID have limited access to stoves and door keys for safety reasons, and may lack the mental capacity to understand safety concerns (Strength of evidence: III, V).

Extant criteria state that the person has recognized that the compulsions are excessive or unreasonable. Note that this does not apply to young children (APA, 2000). Nor does this criterion apply to adults with developmental ages, or abstract reasoning skills, similar to those of young children. Most children over the age of 8 are aware that their obsessive thinking is abnormal. By extrapolation, children or adults with developmental ages under 8 years are unlikely to be aware that their obsessions and compulsions are abnormal. Furthermore, a person must have internalized concepts of normal or socially acceptable behavior, plus the capacity to make comparisons and judgments about behaviors, to be able to judge whether their own behavior is unusual or abnormal. For these various reasons, the diagnostic requirement that the person with OCD recognizes that his or her compulsions are excessive or unreasonable does not apply to persons with developmental ages of young children, and corresponding ID (Strength of evidence: V).

The DSM-IV-TR diagnostic requirement that the obsessions or compulsions cause marked distress (APA, 2000) may not be applicable to many individuals with ID and OCD given that they may (a) lack social awareness of how inappropriate such behaviors are and do not feel distress about them, (b) lack judgment to evaluate how unsafe or unacceptable such behaviors are and do not feel distress about them, and (c) lack the language skills to report subjective feelings of distress (Strength of evidence: V).

DSM-IV-TR states that a diagnosis of OCD should be reserved for obsessive-compulsive activities that are truly interfering with the person’s life and not merely excessive (i.e., that take more than one hour per day, APA, 2000). The diagnostic requirement that OCD can be diagnosed if the obsessions or compulsions take more than one hour per day may be invalid or misleading in individuals with ID. Some individuals with ID who spend a total of one, two, or more hours a day doing their morning hygiene in a fixed sequence, getting dressed just so, eating in a fixed order, and taking a fixed route to work, function very well and could be described as having ‘subclinical OCD.’ Their compulsions are not interfering with their routine, but have become an integral part of their daily routines. When an individual with ID shows many compulsive activities and such actions are not significantly interfering with their normal routine, usual social activities or relationships, the criterion of excessive time ought to be suspended. ‘Subclinical OCD’ refers to one part of a continuum of obsessive-compulsive phenomena where the symptoms have minimal interference in the person’s life (Apter et al., 1996). A diagnosis of OCD should be reserved for obsessive-compulsive activities that are truly interfering with the person’s life and not given if the only criterion met is that non-problematic rituals exceed one hour per day (Strength of evidence: V, IV).