William I. Gardner, Ph. D., Emeritus Professor Rehabilitation Psychology Program, University of Wisconsin-Madison
Impulse control difficulties represent a major feature of a number of behavioral and mental disorders in children, youth, and adults with intellectual disabilities (ID). These difficulties of impulse control can play a prominent role in such actions as physical violence, property destruction, pyromania, paraphilia, trichotillomania, self-injurious behavior, oppositional behavior, and a range of other behavioral difficulties and mental disorders. In fact, in discussion of the presence of impulsivity as a prominent feature in a number of DSM-IV Axis II personality disorders, Coles (1997) noted that impulsivity is "widely considered to be a characteristic of the other major Axis II category, mental retardation"(p. 188). Problems of impulse control thus are frequently encountered by professionals working in the care and treatment of persons with a mental handicap and represent both diagnostic and treatment challenges.
This paper examines the concept of impulsivity and its developmental pathways. Using a developmental psychopathology framework, the role of impulse control disorders within a broader context of mental disorders is highlighted. Both biomedical and psychological conceptualizations are offered as a basis for management and treatment approaches.
Definition and Terminology of Impulsivity
Even a casual reading of the psychological and psychiatric literatures reveals that the concept of impulsivity is complex in nature and does not enjoy a comprehensive uniform and consistently used definition or related terminology. In referring to impulsivity, most writers describe three components involving (a) an impulse, (b) an ensuing impulsive act, and (c) the conditions or situation in which the sequence of impulse ==> impulsive behavioral act occurs. Further, the impulse is described as having motivational properties of behavioral activation as well as behavior selection and specificity, e.g., to pull hair, to start fires, to smoke, to molest a child, to be aggressive toward others, to self-mutilate. More specifically, a person with a diagnosis of trichotillomania, in response to an activating urge or impulse, engages in hair pulling acts rather than other activities such as reciting poetry or urinating on the heating ducts.
Additionally, writers typically imply that the impulsive behavioral act is beyond the personal control of the individual. This is noted in use of such descriptions as "lack of inhibitions," "unpremeditated," "more reflexive than volitional action," in the presence of an" "irresistible urge," and thus "compelling the person to act" in a manner that is "beyond rational control," and thereby the impulsive behavioral act reflects "irrationality," and a "hastiness," in response to a "welling up of drive to act." These and similar terms denote an absence of executive function or deliberate cognitive mediational influence, consideration, or deliberation of circumstances or consequences of the impulsive act.
Descriptions of impulse control also suggest a further conceptual and definitional distinction. Terms such as "lack of inhibitions" imply the absence of or weak impulse control features while terms such as "disinhibition" and "impulse dyscontrol" suggest an impairment of impulse control or inhibitory processes that typically or historically is or has been present. These terms more frequently are used to label loss of inhibitions due to various neurobiological abnormalities such as severe alcohol intoxication or neurological impairments associated with dementia or injury to the frontal lobes (American Psychiatric Association, 1994). Coles (1997, pp. 184-185) also noted that distinction should be made between impulsivity and activities that reflect major impairments in affect, mood, or emotions such as the irritability of dementia due to Huntington's disease, mood lability of alcohol intoxication and manic episodes, the irritability or anxious mood of cannabis-related disorders, and the poor-low frustration tolerance of major depressive episodes. These mood and affective states, while different from impulsivity, may render more likely the occurrence of impulsive acts under more specific impulse activation conditions.
The implication in this distinction is that the person's impulse control on occurrence of an impulse to act is disinhibited under these major neuropsychiatric impairment conditions and, that under more normal mood or emotional conditions, the person could demonstrate more typical control of impulses. As noted later in this paper, pharmacological interventions appear to be most successful in addressing these contributing emotional or mood conditions rather than directing alleviating the difficulties of impulse control that reflect the absence of or inadequately developed impulse control skills.
In sum, a person with impulse control difficulties is described at the time of the impulsivity as being compelled to engage in the impulsive act, as being unable to exert cognitive inhibitory control or resistance over the impulse or urge to act in a manner that has the potential for harm to self or others. The diagnostic and related therapeutic implications of such impulsivity are evident and are discussed in subsequent sections.
Impulsive vs. Controlled Behavioral Acts
As noted, definitions typically contrast impulsive behavioral acts that have the potential for harm to the person or others with those behavioral acts that are functional for the person, are planned, controlled, deliberate, and are under effective rational cognitive self-controlling personal features. On some occasions this seemingly logical distinction becomes a bit fuzzy. Well-practiced acts of self-defense as examples, may be functional and become quite habitual and seemingly reflexive, as these occur on appropriate occasions without mediated deliberation. Some writers thus suggest that distinction be made between "functional impulsivity" and "dysfunctional impulsivity" (Dickman, 1990).
Variability in Impulsivity
These and similar descriptions also indicate that impulsivity is not an all-or-nothing feature of a person. Each person experiences a variety of impulses and varies in the manner in which these are acted upon. Lack of impulse control may be descriptive of a person's actions across a number of situations and impulses or may be restricted to specific impulses, motives, drives, temptation areas, or emotional states (e.g., impulsive behaviors involving smoking, ingestion of dangerous objects, setting fires, excessive water intake, hair pulling, stealing, acts of violence, molesting children, self-mutilation, academic tasks, and the like). The obesity, excessive use of alcohol and tobacco, and overindulgence in work and sex to the detriment of a person's physical, psychological, and interpersonal well being all attest to the variability between self-controlled and impulsive actions. Thus, a person can be quite self-controlled in numerous aspects of his or her life (e.g., consistent in resisting temptation to engage in illegal behaviors) and quite impulsive and reflexive in other areas of life (e.g., eating high fat food even when knowledgeable about high personal cholesterol levels and the related detrimental health effects) to the extent that short and long term negative consequences ensue. As discussed in the following sections, problems of impulse control are magnified in persons with features depicting various mental disorders and among persons with limited cognitive skills that interfere with development and effective use of self-controlling skills to inhibit impulses to respond. As implied earlier, impulsivity is generally viewed as a common feature of persons with ID, especially among those with increasingly limited cognitive and language skills.
Impulsivity and DSM-IV Disorders
Impulsivity and difficulties in impulse control occur as features of most DSM-IV Axis I and Axis II disorders (APA, 1994). In the general section on "Impulse Control Disorders Not Otherwise Classified," with an essential defining feature of failure to resist an impulse, drive, or temptation to perform an act that is harmful to the person of to others," descriptions are provided of intermittent explosive disorder, kleptomania, pyromania, pathological gambling, trichotillomania, and impulse-control disorder not other wise specified. Other disorders with features that may involve problems of impulse control include substance-related disorders, paraphilias, borderline and antisocial personality disorders, conduct disorders, schizophrenia, and mood disorders. Thus, problems of impulse control are pervasive among persons with the dual diagnosis of ID and mental health disorders. Some disorders reflect primary deficits in self-controlling features while others disorders reflect temporary or more long lasting loss of control related to disruption of neurological integrity.
A Developmental View of Impulsivity
Impulsive destructive and related disruptive behaviors in adults with ID predominately represent social behaviors that been influenced over time by the effects produced by these acts. Exceptions may be seen in reflexive or involuntary reactions associated with painful aversive stimulation, infrequently occurring involuntary aggressive movements associated with seizure disorders, or organically-related rage arousal levels that may serve a major instigating role in influencing occurrence of impulsive aggressive acts (Barnhill, 1999; Gedye, 1989). Even in these instances, the personal and environmental effects produced by these acts serve to influence the likelihood of recurrence whenever the person is exposed to similar conditions of impulse instigation. During the developmental years, a range of biomedical and psychosocial conditions acts as risk factors and contribute to the occurrence, and repeated recurrence, of impulsive modes of responding to various activating conditions.
A study of impulsive destructive and disruptive behavior patterns within the framework of developmental psychopathology examines the historical physiological, psychological (affective, cognitive, behavioral), and social environmental characteristics and related experiences of a person (Cicchetti & Cohen, 1995; MacLean, Stone, & Brown, 1994). This is undertaken to understand the manner over the course of the person's life span in which these interactive classes of characteristics have contributed to the origin and habitual recurrence of impulsive destructive and other disruptive behaviors. Few studies are available that describe the developmental course over time of impulsive behavior problems among persons with ID. It is reasonable to assume nonetheless that related destructive and disruptive behaviors in people with mental retardation develop in the same way as does similar impulsive activities in persons without significant cognitive impairments (MacLean, Stone & Brown, 1994).
Early Origins of Impulsive Disruptive Responding
During the early developmental years, the very young child initially reacts in a semi-differentiated rage manner at sources or conditions of restriction or aggravation. At around age two, impulsive acts typically are seen in attempts to obtain a desired object from another child. In the ensuing months and years, as a result of neurological maturation and the assimilation of the socialization experiences, such impulsive acts as fighting, temper tantrums, attacking, and property destruction typically reduce for most children. These emerging self-controlling features reflect a normal neurological development in interaction with social experiences that stimulate their expression. Some writers suggest these evolving personal features are guided by an underlying instinct for self control that emerges from the neurological development and sustained by a social environment that supports its appearance and use (Barkley, 1997). This supposition was advanced much earlier by Darwin (1871/1992) who suggested "It is possible or as we shall see later, even probable, that the habit of self-command may, like other habits, be inherited" (p. 314).
This evolving self-control becomes evident during the time that most children acquire two critical sets of skills. First, the child acquires skills to inhibit disruptive impulse-related emotional arousal and random impulsive responding. The second set involves skills of selecting from an expanding repertoire of coping or problem-solving skills those alternatives that will accomplish the same or similar results of gaining attention, solving problems, and expressing anger, over arousal, and frustration.
A number of biomedical and psychosocial risk or vulnerability factors, however, may compromise this developmental learning sequence, impede the evolution of this typical socialization process, and leave a child with ID with stronger than typical features of impulsivity. Simply stated, a child may remain at a more primitive earlier level of socialization. Without critical skills to control or inhibit impulses or to select alternative coping skills, the child is prone to continue use of impulsive acts when confronted with a range of conditions of provocation. These compromising influences may include a range of both biomedical and psychosocial conditions.
Developmental Risk Factors for Impulsive Responding in Children with ID
More specifically, children with ID and other developmental disabilities are at increased risk for continuation and elaboration of the impulsive-like responding developmentally typical of the young child. Brief discussion is provided the following significant risk factors:
"features of temperament,
"parenting and related dysfunctional social experiences,
Temperament and Impulsive Destructive Acts
Although no systematic studies have been conducted of the role of temperament in development of impulsive destructive acts in persons with ID, some writers have noted the relationship between a child's temperament and the nature of interactions with the environment (Chess, 1971; Webster, 1971). Temperament refers to "constitutionally based individual difference in behavioral style that are visible from early childhood (Sanson & Prior, 1999, p. 397)." Differences in temperament among children are reflected in reactivity to internal and external stimulation and in patterns of motor and attentional self-regulation. As such, temperamental features represent the emotional, motivational, and attentional basis for the developing personality (Sanson & Rothbart, 1995).
Three aspects of temperament that emerge relatively consistently in children are those of (a) positive affects and approaching tendencies, (b) negative emotionality, and (c) effortful control or self-regulation (Sanson & Prior, 1999). Although temperament is viewed as a biologically based construct, a child's experience with the environment may either reduce or magnify individual differences in temperament features. In general, children may change to some degree over time but stability of features is not unusual.
Negative emotionality is viewed as an irritable affective state or readiness for outbursts of anger and aggressive reactions. This feature is seen as involving impulsivity as reflected in intense and highly reactive responses to a variety of situations, and inflexibility which encompasses resistance to control, unmanageability, and nonadaptability. It also may be described as a negative irritable temperament style
Negative emotionality is viewed as a vulnerability or predisposition for continued impulsive destructive responding. When viewed within a transactional model, the risk or vulnerability becomes activated when other adverse circumstances of the child's environment co-occur (stressors in the family environment; poor parenting interactions with the child). The continuous interactions over the developmental years between the child's temperament features and the environment result in a negative outcome. The tendency to a demanding or coercive type of behavioral disposition as an intrinsic temperamental precursor will impact parental practices that in turn may magnify the temperament features. To illustrate, a temperament cluster of difficultness that comprised negative emotionality, nonadaptability to the new, and resistance to control was associated with negative management interactions and conflict with parents. Patterson, Reid, and Dishion (1992) provide detailed description of the ensuing coercive interaction style.
As noted, during the developmental years the typical young child demonstrates a decline in random display of rage and related impulsive behaviors and replaces these undifferentiated reactions with increasingly focused coping skills. These behaviors of a coping nature may involve discriminated acts of aggression and other disruptive acts directed toward specific victims. Gradually, as inner controls are learned due to neurological maturation and in response to socialization experiences, the child develops more socially acceptable and effective coping approaches, including impulsive control, anger management and interpersonal conflict resolution. Rules of desired interpersonal behaviors comprising both cognitive and affective components are assimilated into the child's evolving personal inhibitory impulse control structure. As a result of these interrelated socialization processes, impulsive destructive responding, especially of a physical nature, becomes an unusual occurrence for the majority of children. These personal and social characteristics reflecting interrelated cognitive and affective impulse control mechanisms become increasingly complex during adolescence and adulthood and continue to insure that destructive impulsivity is minimized.
The child with ID characterized by cognitive and related language impairments is at a distinct disadvantage in this learning process and is unable to fully benefit from critical early developmental experiences even if these were provided. The child with ID becomes delayed in developing essential self-controlling skills and related problem solving skills useful in inhibiting the continued expression of aggressive responding. To illustrate, there typically are deficits in self-control skills involving self-delivery of various inhibitory cues. The child is unlikely to inhibit impulses to behave disruptively by using such covert self-talk as, "Don't hit Sue. I'll get in trouble. Just ignore her. Turn away from her and don't let her get me too upset." Thus the child is less likely to acquire the skills to self-deliver inhibiting cues to him or herself to control impulsive aggressive acts.
Additionally, the child with cognitive impairment is less likely to acquire other skills of important in controlling impulsive destructive acts and in negotiating interpersonal conflicts (Gardner, 1998). The person has difficulty learning to use verbal skills of mediation such as self-monitoring (e.g., saying to oneself "I'm getting too upset and will lose my temper."), self-consequation (e.g., That's great! I calmed down and didn't yell at him!), self-instruction (e.g., Just relax now. Calm down") to cope with problem situations and to self-influence alternative adaptive behaviors. The child with ID typically learns few self-generated statements of caution or redirection that serve to inhibit various impulsive and disruptive reactions, or few self-generated cues for positive interpersonal or emotional reactions. Thus, the child with cognitive limitations is more likely to "be at the mercy" of whatever internal or external provoking stimulation that may occur and, as a result, is likely to be controlled by these impulses.
Restriction in the acquisition and rational selection of socially appropriate coping alternatives to impulsive responding represents a second major debilitating effect of cognitive limitations. During the socialization process, the child learns not only to inhibit impulsive responding but also acquires a number of behaviors as appropriate alternative ways of coping with the various impulses and related sources of provocation. Thus, the repertoire of potential coping behaviors expands as the child develops and serves as effective alternatives to impulsive responding.
As a result, a child with ID, especially when more severe cognitive impairments are present, may continue to display impulsive and rage-related destructive attacks in a relatively non-discriminating manner under a range of interpersonal and environmental conditions. These impulsive-like behavioral outbursts most typically become increasingly likely as a result of the contingent consequences produced by the disruptive acts. These consequences match one of two classes of activating or motivating conditions. The impulsive acts may result in the removal, delay, or reduction in conditions that triggered the impulse. Additionally, the impulsive acts may become the most successful means in the child's repertoire to insure reduction of the urge or impulse. As a result of this impaired developmental learning process, impulsive responding may become quite predominant and reflexive in nature as it represents a most effective and efficient coping behavior, and the one most available to the child whenever confronted with conditions that create distressful impulses.
In sum, the typically developing child acquires an increasingly large number of coping behaviors from which to select in a discriminating manner to match specific conditions of impulses to respond. In contrast, the person with ID and the limitations in cognitive skills and resulting impaired behavioral repertoires overuses the most effective and efficient reaction available. As a result, the habit strengths of impulsive actions become quite strong and following excessive use increasing resistant to extinction and replacement with more socially appropriate alternatives.
Parenting and Related Dysfunctional Interpersonal Experiences
A number of psychiatric epidemiological studies, some of which include persons with mental retardation (Richardson, Koller, & Katz, 1985; Rutter, 1989), have implicated parenting and related dysfunctional interpersonal and social experiences as risk factors for development of emotional and cognitive features t hat contribute to impulsive means of interacting in interpersonal situations.
One critical outcome of these dysfunctional experiences involves difficulties in emotional regulation observed in children with mild to more severe ID (Bradley, 2000; Greiger & Crick, 2001; Sroufe, 1996).
Faced with the multiple demands of caring for a child with disabilities, caregiver resources may be increasingly taxed by a child's temperament features of impulsivity, reactivity, and inflexibility. These resources may be taxed even further in the context of a dysfunctional family unit that includes such conditions as protracted marital conflict and parental violence and abuse. Such caregiver features as parental rejection, an excessively demanding and unpredictable punitive demeanor, excessive restrictiveness and related negative management interactions and conflict, and depression have all been implicated as influencing the development and perpetuation of an impulsive and anger-related mode of interactions (McGee & Williams, 1999; Richardson et al., 1985). A central feature of this impulsive inclination is impairment in the ability to regulate the level of emotional arousal.
The foundation for development of skills to regulate one's emotional arousal level is acquired during infancy and early childhood. A critical feature of this learning experience is the presence of an emotionally responsive caregiver that is available on a consistent manner, especially at times of stress. Sroufe (1996) suggests that such emotions as fear and anxiety become palatable to an infant as these emotions become associated with the caregiver's soothing support during times of arousal. The infant gradually learns to regulate his or own arousal level after repeatedly experiencing the soothing relief provided by the attentive caregiver following periods of emotional disorganization. With the passage of time, the infant is able to tolerated more intense emotions without extended and excessive disorganization with the assurance that a settled state will follow.
In the absence of a caregiver that provides consistent responsive soothing care, emotional arousal may be experienced as excessively unsettling. As a result, adequate skills of self-regulation of emotional arousal may never develop, or if partially developed, may easily be overridden by intense levels of arousal that may be produced by a range of environmental and covert provocations. This difficulty of acquiring skills of emotional regulation in persons with ID is compounded by features of temperament, level of cognitive impairment, and by other socio-environmental conditions. Emotional dysregulation thus may become a key component in impulsive acts that occur under even seemingly minor sources of provocation. In the absence of adequate functional emotional regulation skills, a child has considerable difficulties in self-regulating behaviors that result from excessive and sometimes prolonged emotional arousal.
Psychobiological Contributions to Impulsivity in Persons with ID
Writers classify destructive and related disruptive behavioral acts either as impulsive, affective, or reactive in nature or as being premeditated or instrumental in nature (Kavoussi, Armstead, & Coccaro, 1997; Sheard, 1984; Waslick, Werry, & Greenhill, 1999). Hyperarousal and increased sympathetic activity associated with neurological compromise characterize impulsive-driven destructive behavioral acts. The behavioral acts tend to be explosive in nature with increased levels of irritability frequently out of proportion to the provoking event
A range of general and specific neurological and neurochemical abnormalities characterize a significant numbers of persons with mental retardation. These are presumed to contribute to:
"An inclination for generalized affective overarousal (also presented as hyperexcitability, hyperirritability, hypersensitivity) even to minor conditions of threat or aggravation. This overarousal may involve such emotions as fear, anxiety, irritability, and anger
"As described previously, difficulties in modulating the state of overarousal with the result that the person is unable to stabilize or lower the excessive arousal level. This affective dysregulation may culminate in a rage reaction or result in rapid shifts in emotional states.
"Difficulties of inhibiting exaggerated impulsive reactions toward the perceived source of these distressful states.
These psychobiological difficulties, and especially a pattern of overreactivity to seemingly minor sources of provocation, are present with increased frequency and severity among persons with more severe cognitive and adaptive behavior impairments (Gardner & Sovner, 1994; Sovner & Fogelman, 1996). As noted earlier, similar difficulties are present among persons with mental retardation who also present with various psychiatric and personality disorders (Bradley, 2000; Coccaro, 1989; Greiger & Crick, 2001; Mavromatis, 2000; Reiss, 1994).
Even though the specific neurobiological structures and processes that underlie the overarousal, difficulties in modulating these affective states, and difficulties in inhibiting the resulting impulsive responding in persons with developmental disabilities have not been determined in any precise detail, various writers have offered some valuable speculations that address the psychobiology of hyperexcitability and irritability (Coccaro, 1989; Kavoussi et al., 1997; Sovner & Fogelman, 1996). As illustration, Sovner and Fogelman (1996) propose an "Organic Irritability Syndrome" with defining criteria of persistent irritability with associated self-injury, aggression or property destruction pervasive over reactivity or disturbed sleep of an least two-years' duration, significant CNS damage, and these and related symptoms not being accounted for by another psychiatric disorder. These writers highlight the highly distressful nature of persistent irritability and the role that this subjective state can assume in the genesis and persistence of impulsive destructive acts.
A number of writers have suggested that impulsive patterns of destructive actions that primarily are affective or emotionally based represent suitable candidates for psychopharmacological intervention. As noted, such impulsive acts correlates more clearly with biologic indices of neurotransmitter function (Campbell, Gonzales, & Silva, 1992; Vitello, Behar, Hunt, Stoff, & Ricciuti, 1990; Waslick et al., 1999). In a similar manner, other writers describe the impulsivity, irritability, and mood lability features of persons with more severe levels of cognitive impairment who engage in repetitively and impulsively engage in destructive behavioral acts as reflecting neurophysiologic dysregulation (Barnhill, 1999; Mikkelsen & McKenna, 1999; Sovner & Fogelman, 1998).
A central serotonergic (5-HT) system dysfunction hypothesis is offered that implicates a reduced or hyposerotonergic state underlying hyperirritability, hyperexcitability, and hypersensitivity. This lower threshold for responding places a person at increased risk for reacting in an exaggerated impulsive fashion when exposed to relatively minor conditions of provocation. Sovner and Fogelman (1996) offer an additional hypothesis that decreased CNS 5-HT function influences irritability and associated impulsive aggression via loss of inhibition of limbic dopaminergic activity. These two paradigms offer specific pharmacological treatment implications.
In a related manner, Gray (1987) has proposed three related psychobiological models that provide some possible additional insights into the impulsive and seemingly uninhibited exaggerated nature of impulsive acts. These consist of the Behavioral Activation System (BAS), the Behavioral Inhibition System (BIS), and the Fight/Flight System.
The BAS and BIS regulate reinforcement-based learning and emotion. The BIS, most relevant to the current discussion and related to punishment and anxiety, is represented in the brain "primarily by noradrenergic projections from the locus ceruleus and serotonergic (5-HT) projections from the brainstem raphe nuclei to diverse areas of the lower brain and higher cortical centers" (Waslick et al., 1999, p. 457). Quay (1997) suggested that the BIS provides for "the cessation of ongoing behavior, an increase in nonspecific arousal, and a focusing of attention on relevant environmental cues" (p. 8). When the BIS is functional, impulses to engage in destructive behaviors that are perceived by the person as being likely to result in aversive consequences are likely to be inhibited.
A dysfunctional BIS associated with a hyposerotonergic state, in contrast, may increase a person's tendency to engage in uninhibited impulsive reactions to conditions of aversive arousal. It is speculated that conditioned cues for punishment do not activate fear or anxiety as possible inhibitory conditions. In this scenario, aversive incoming stimuli and the resulting impulsive inclination bypass the BIS (i.e., are not modified or inhibited by this system) and thus are processed into impulsive actions toward the source of instigation.
The Fight/Flight System (F/F), a related system described by Gray (1987), results in protective actions of fight or flight when a person interprets events of provocation as posing a threat. When the F/F system is hypersensitive, exaggerated impulsive actions may occur to minor sources of provocation. The person thus is prone to overreact. As noted, a pattern of overreactivity to seemingly minor sources of provocation is present in a significant number of persons with lengthy histories of impulsive aggression, especially among those with various psychiatric and personality disorders (Bradley, 2000; Greiger & Crick, 2001) and in those with more severe levels of cognitive impairment (National Institutes of Health, 1991). Barnhill (1999), in recognition that more extreme forms of impulsivity appear to be associated with intense autonomic/ sympathetic arousal, suggests that the impulsive acts "represent an activation of the flight or fight mechanisms. Compromised frontal lobes, especially the right orbito-frontal cortex, reduce the top-down regulation of the fear system" (p. 45).
In a related contribution, Ratey (2001) identifies the amygdala as the neurological structure most involved in experiences of fear or anxiety. "Stimuli have a direct pathway through the sensory filter of the thalamus to the amygdala, which then can mobilize the body through its brainstem connections" (p. 233). Ratey notes that a programmed aggressive response to threat is etched into the amygdala. This response is activated when a person perceives conditions as posing a threat. With neurological and psychological maturation, however, such information is processed through the thalamus to the frontal cortex where more deliberate attention may be given to the nature of the information and related means of coping with it. The writer describes these as the low road and high road of responding to events perceived as threatening. "Apparently there is a gradual shift of emotional and cognitive processing from the instinctive to the cognitive regions (Ratey, 2001, p. 234).
As described earlier, a significant percentage of persons with ID, especially those with more severe levels of cognitive and related language impairments, only partially if at all make this shift from impulsive responding to more considered cognitive processing of emotional content. Thus the automatic circuits in the brain may not be rearranged into more discriminated responding.
Ratey (2001) further suggests that persons who engage in impulsive destructive acts as a means of coping often have under active frontal lobes. Without the inhibitory influence of the frontal cortex, overarousal may occur to instigating conditions. This in turn may override any psychological inhibitions that typically may be used when not over stimulated. Brain trauma and Attention Deficit Hyperactivity Disorder are offered as possible contributors to states of overarousal. Additionally, the writer suggests that uninhibited impulsive responding under conditions of overarousal may be intensified by difficulties in expressing ones thoughts and emotions and by strong habits of destructive responding, both common features of persons with more severe levels cognitive impairment. Finally, Ratey (2001) noted: "Breaking the cycle of low inhibition and overstimulation, however, is made more difficult when a person learns that acting on aggressive impulses will bring a kind of relief. Addiction to aggression as a way to solve problems and relieve frustration can make it very difficult for the angry person to change" (p. 238).
An observation by Bradley (2000) offers some insight into the psychobiology of the treatment resistant nature of impulsive destructive habits. This writer suggested that following repeated use of impulsive destructive responding "neural circuit changes-for example, intensification of connectivity between amygdala-hippocampus "attack" circuits-may become easily activated with any kind of arousal" (p. 20). Thus a person acts impulsively without the central processing benefits of more deliberate problem solving activities. This observation also may account for the puzzling episodes of impulsive aggressive acts of some individuals even when in a seemingly "happy" state of heightened arousal.
Psychological Analysis of Impulse Control
Locus of Control of Impulsive Actions
Control of impulsive actions may arise from internal or external sources. Internal sources of control may reflect either psychological or pharmacological management. Psychological management processes refer to those covert self-controlling events that address the impulse and inhibit its expression, typically through self-modulating the arousal level of the impulse and through selecting and engaging in some competing coping acts. Pharmacological management refers to use of various medications that remove or reduce emotional or cognitive mental states that (a) contribute to the impulse and related impulsive acts or that (b) serve to disinhibit self-controlling features of the person.
External environmental controls may occur whenever the person is discouraged from engaging in impulsive acts by restricting access either to the object arousing the impulse or to those objects required to engage in the impulsive act (e.g., a person with pedophilia is not permitted to look at pictures of children or to be in environments in which children are present) or by social supervision (e.g., a person who is inclined to set fires is supervised whenever in the presence of fire-setting materials). Attention in this section is given to these impulse controlling processes, the limitations of components of these in persons who display impulsive actions, and, following identification during diagnostic assessment, the nature of the diagnostically-based interventions needed to address these inhibitory and related psychological skill deficits.
Psychological Impulse Controlling Processes
Impulse controlling activities may involve either (a) active self-controlling processes or (b) automatic actions occurring without active cognitive or affective processing or problem solving that have gradually become habitual as a result of successful coping processes on numerous previous occasions. The active self-controlling processes consist of two groups of skills. The initial group of skills represent those used to deliberately control, block, or inhibit expression of impulses to engage in such acts as fire setting, hair pulling, sexually inappropriate behaviors, or destructive acts directed toward self, others, or property. The second group of self-controlling skills are those complementary ones used to (a) reduce the frequency and intensity level of the impulses under conditions of impulse arousal and (b) those personal features involved in selecting available prosocial alternatives modes of expression when confronted with impulses for deviant behaviors.
Diagnostic Assessment as a Basis for Selection of Management and Treatment
The initial diagnostic assessment task for an individual's impulsive actions becomes one of determining if the impulsivity represents (a) skill deficits (Functional self-controlling skills are not in a person's repertoire.) or (b) performance abnormalities (Impulse -controlling skills are or have been in a person's repertoire but currently are not used under conditions of impulse arousal). In these cases of disinhibition, distinction is made between more permanent loss due to neurological damage of brain centers critical to their use or temporary loss due to effects of such substances as alcohol or drugs. To elaborate:
"Does the absence of impulse control reflect the disinhibiting effects of CNS injury or damage?
"Does the performance lapse represent the temporary disinhibiting effects of alcohol or drug use?
"Does the performance lapse reflect the disinhibiting effects of features of various mental disorders (e.g., high levels of anxiety, irritability, anger, hostility, mania) or other medical conditions (e.g., pain or irritability)?
"Do psychological influences such as insufficient motivation to use self-controlling skills to inhibit specific impulses account for the performance difficulty?
Diagnostic information relevant to each of these questions would provide the basis for selecting pharmacological and/or psychological interventions.
Impulsivity Reflecting Skill and Related Motivational Deficits
1. Diagnostic Task. Identify deficits in self-controlling or impulse inhibitory skills and possible related deficits in affective and motivational features for using these skills in a discriminating manner under impulse provocation.
1a. Focus of Intervention. Teach and strengthen mediating cognitive strategies such as those involved in self-monitoring, self-evaluation, and self-direction. Additionally, attention is devoted to developing or enhancing the motivational basis for using these self-controlling skills in a discriminating manner under conditions of impulse provocation (Benson, 2002; Gardner, 1998).
2. Related Diagnostic Task. (a) Identify impulse reduction skill deficits, that is, those involved in reducing the occurrence and/or intensity of impulses to destructive acts. (b) Identify related skill deficits in prosocial alternative modes of acting in the presence of impulses for maladaptive behaviors.
2a. Focus of Intervention. (a) Teach skills to self-monitor and reduce occurrence and intensity of those impulses and related states of arousal that control impulsive behaviors. (b) Teach prosocial alternative actions and the motivational supports for using these alternatives (Benson, 2002; Cole, Gardner, & Karan, 1985; Gardner, 1998; Singh, Wahler, Adkins, & Myers, 2003).
Impulsivity Reflecting Performance Deficits.
In those instances in which a person's impulsive responding represents a change from a recent history in which the person had demonstrated more controlled and socially appropriate behaviors under the environmental conditions in which the impulsive behavior now occurs, the diagnostic task becomes one of identifying the nature of the influences that serve as a disinhibiting influence over the previously observed impulse controlling resources. The impulsive behaviors may be occurring under unusual or major sources of external or internal instigating conditions or may begin to occur under seemingly minor sources of external of external provocation. Examples of these include symptoms of psychiatric conditions, e.g., hypersexual arousal when in a state of hypomania or other medical conditions such heightened irritability level associated with a severe headache in a person with mild intellectual disabilities resulting in a disinhibited outburst of verbal aggression when teased by a peer.
1. Diagnostic Task for Impulsivity Reflecting the Disinhibiting Effects of CNS Injury or Damage. Identify the neurological condition contributing to the disinhibition of those impulse controlling personal features that were present prior to occurrence of neurological pathology.
1a. Focus of Intervention. Use pharmacological and environmental management strategies to reduce the presence of environmental and interpersonal impulse provoking conditions.
2. Diagnostic Task for Impulsivity Reflecting the Temporary Disinhibiting Effects of Alcohol or Drug Use. Identify the alcohol or drugs that are contributing to disinhibition of previously used impulse control skills.
2a. Focus of Intervention. Reduce or eliminate excessive use of alcohol or drugs producing the disinhibiting influence.
3. Diagnostic Task for Impulsivity Reflecting the Disinhibiting Effects of Features of Various Mental or Other Medical Disorders. Identify the mental or medical conditions that contribute to the disinhibition of impulse control skills.
3a. Focus of Intervention. Treat the mental or other medical conditions identified as producing the symptoms (irritability, overarousal, hypersexuality, pain) influencing the disinhibition of impulse control skills.
4. Diagnostic Tasks for Impulsivity Reflecting Motivational Features. In some instances, alternative self-controlling skills are in the person's repertoire but are not valued by the person. The diagnostic task becomes one of identifying these motivational limitations and the reinforcing conditions that result from the impulsive acts.
4a. Focus of Interventions: Interventions are designed to increase the value of alternatives to the impulsive act, decrease the value associated with the impulsive act, and in selected cases, to increase the negative emotional arousal level associated with occurrence of the impulse act. This latter strategy is designed to enhance inhibition of the impulsive act and to encourage use of a prosocial alternative.
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