Compulsive aspects of impulse-control disorders

Probing compulsive and impulsive behaviors, from animal models to endophenotypes: a narrative review

Failures in cortical control of fronto-striatal neural circuits may underpin impulsive and compulsive acts. In this narrative review, we explore these behaviors from the perspective of neural processes and consider how these behaviors and neural processes contribute to mental disorders such as obsessive-compulsive disorder (OCD), obsessive-compulsive personality disorder, and impulse-control disorders such as trichotillomania and pathological gambling. We present findings from a broad range of data, comprising translational and human endophenotypes research and clinical treatment trials, focussing on the parallel, functionally segregated, cortico-striatal neural projections, from orbitofrontal cortex (OFC) to medial striatum (caudate nucleus), proposed to drive compulsive activity, and from the anterior cingulate/ventromedial prefrontal cortex to the ventral striatum (nucleus accumbens shell), proposed to drive impulsive activity, and the interaction between them. We suggest that impulsivity and compulsivity each seem to be multidimensional. Impulsive or compulsive behaviors are mediated by overlapping as well as distinct neural substrates. Trichotillomania may stand apart as a disorder of motor-impulse control, whereas pathological gambling involves abnormal ventral reward circuitry that identifies it more closely with substance addiction. OCD shows motor impulsivity and compulsivity, probably mediated through disruption of OFC-caudate circuitry, as well as other frontal, cingulate, and parietal connections. Serotonin and dopamine interact across these circuits to modulate aspects of both impulsive and compulsive responding and as yet unidentified brain-based systems may also have important functions. Targeted application of neurocognitive tasks, receptor-specific neurochemical probes, and brain systems neuroimaging techniques have potential for future research in this field.

Is there an inhibitory-response-control system in the rat? Evidence from anatomical and pharmacological studies of behavioral inhibition

Many common psychiatric conditions, such as attention deficit/hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), Parkinson's disease, addiction and pathological gambling are linked by a failure in the mechanisms that control, or inhibit, inappropriate behavior. Models of rat behavioral inhibition permit us to study in detail the anatomical and pharmacological bases of inhibitory failure, using methods that translate directly with patient assessment in the clinic. This review updates current ideas relating to behavioral inhibition based on two significant lines of evidence from rat studies: (1) To integrate new findings from the stop-signal task into existing models of behavioral inhibition, in particular relating to 'impulsive action' control. The stop-signal task has been used for a number of years to evaluate psychiatric conditions and has recently been translated for use in the rat, bringing a wealth of new information to behavioral inhibition research. (2) To consider the importance of the subthalamic nucleus (STN) in the neural circuitry of behavioral inhibition. This function of this nucleus is central to a number of 'disinhibitory' disorders such as Parkinson's disease and OCD, and their therapies, but its role in behavioral inhibition is still undervalued, and often not considered in preclinical models of behavioral control. Integration of these findings has pinpointed the orbitofrontal cortex (OF), dorsomedial striatum (DMStr) and STN within a network that normally inhibits many forms of behavior, including both impulsive and compulsive forms. However, there are distinct differences between behavioral subtypes in their neurochemical modulation. This review brings new light to the classical view of the mechanisms that inhibit behavior, in particular suggesting a far more prominent role for the STN, a structure that is usually omitted from conventional behavioral-inhibition networks. The OF-DMStr-STN circuitry may form the basis of a control network that defines behavioral inhibition and that acts to suppress or countermand many forms of inappropriate or maladaptive behavior.

Irritable mood and the Diagnostic and Statistical Manual of Mental Disorders

BACKGROUND

The terms 'irritable mood' and 'irritability' have been applied to describe and define a variety of different categories in the Diagnostic and Statistical Manual of Mental Disorders (DSM). More precise diagnostic terms and concepts are needed.

METHODS

A concise critical historical review of DSM categories characterized by irritability, anger, and aggression is presented followed by recommendations.

RESULTS

This analysis describes the broad ranging and imprecise use of the term irritability since the first DSM in 1952. A more age-appropriate and functional realignment of psychiatric categories linked to dysfunctional anger is suggested. Among other recommendations, this realignment would remove irritability as a problematic definer in the present DSM mood categories: expand oppositional defiant disorder to include adults; link the callous unemotional subtype of conduct disorder in adolescents to antisocial personality disorder; move intermittent explosive disorder to an appropriate category: and expand the term 'mood' to apply also to dysfunctional anger and anxiety.

CONCLUSION

The non-specific term 'irritability' commonly used in the DSM has had an adverse effect on diagnostic specificity and thereby on treatment. Dysfunctional anger is a major mood disorder which merits a more prominent and better defined representation in psychiatric nomenclature.

Behavioural adverse effects of dopaminergic treatments in Parkinson's disease: incidence, neurobiological basis, management and prevention

Treatment of Parkinson's disease has traditionally focused on the management of motor disability while behavioural disturbances have received less attention. Recently, impulse control disorders and aberrant repetitive behaviours have surged to clinical relevance as they occur during dopamine replacement treatment (mainly with dopamine agonists) and worsen patient and caregiver quality of life. Patients are unable to adequately estimate the negative consequences of their actions and are prone to entertain compulsive reward-seeking activities. This review aims to summarize current evidence on the epidemiology of behavioural disturbances in Parkinson's disease, recent insights into their neurobiological basis and to discuss strategies for management and prevention. Studies from 1990 through to December 2008 were retrieved via searches of the Cochrane Database of Systematic Reviews and PubMed. The mechanisms underlying the development of behavioural disturbances in Parkinson's disease are debated but current evidence points to specific risk factors: male sex, young age at onset, underlying personality traits characterized by high impulsivity and novelty seeking, and personal or family history of addictive disorders. Specifically, in predisposed individuals dopamine replacement therapy leads to overstimulation of dopamine receptors within the mesocorticolimbic pathways and in turn to the development of addictive behaviours, such as impulse control disorders and compulsive medication intake. Since these disturbances affect individuals who have often unremarkable psychiatric history and no cognitive impairment, their identification and management is complex. Compulsive medication intake (described as 'hedonistic homeostatic dysregulation' or 'dopamine dysregulation syndrome') is commonly associated with fluctuations in advanced disease, while impulse control disorders frequently occur in early Parkinson's disease and within normal-range medication dosages. Management primarily requires reduction of dopaminergic therapy but psychosocial support is often required. Use of selective serotonin reuptake inhibitors in the dose used for obsessive compulsive disorders may help, while benefit from atypical antipsychotics is limited in most cases. Deep brain stimulation should be considered with caution in these subjects. Prevention is based on the identification of at-risk individuals and active monitoring. Given the social and potentially medical-legal consequences of these behaviours, we encourage treating physicians to discuss risks with patients before treatment is initiated.

Skin picking behaviors: An examination of the prevalence and severity in a community sample

Body-focused repetitive behaviors such as skin picking have gained recent attention in the psychiatric literature. Prevalence of skin picking has not been well researched and is difficult to estimate; however, consequences of such behaviors can include severe medical complications and impaired social and occupational functioning. Given this, this study examined: (1) the prevalence and severity of skin picking in a nonclinical community sample, and (2) associations between skin picking and other measures of psychological functioning. Three hundred and fifty-four participants completed measures of psychological functioning and skin picking frequency and severity. A total of 62.7% endorsed some form of skin picking and 5.4% reported clinical levels of skin picking and associated distress/impact. Direct associations were found between skin picking and depressive, anxiety, and obsessive-compulsive symptoms, which may support the emotional regulation model of pathological skin picking. To establish proper diagnostic classification of pathological skin picking and optimize treatment planning and outcome, further investigation of functional relationships between skin picking and affective distress is needed.

Weakness of will, akrasia, and the neuropsychiatry of decision making: an interdisciplinary perspective

This article focuses on both daily forms of weakness of will as discussed in the philosophical debate (usually referred to as akrasia) and psychopathological phenomena as impairments of decision making. We argue that both descriptions of dysfunctional decision making can be organized within a common theoretical framework that divides the decision making process in three different stages: option generation, option selection, and action initiation. We first discuss our theoretical framework (building on existing models of decision-making stages), focusing on option generation as an aspect that has been neglected by previous models. In the main body of this article, we review how both philosophy and neuropsychiatry have provided accounts of dysfunction in each decision-making stage, as well as where these accounts can be integrated. Also, the neural underpinnings of dysfunction in the three different stages are discussed. We conclude by discussing advantages and limitations of our integrative approach.

Trichotillomania: neurobiology and treatment

Trichotillomania is a disorder characterized by repetitive hair pulling, leading to noticeable hair loss and functional impairment. This paper provides an overview of what is known of trichotillomania from several perspectives. We begin by considering historical descriptions of hair pulling that ultimately contributed to the inclusion of trichotillomania as a formal diagnostic entity in the Diagnostic and Statistical Manual. Psychological factors involved in the mediation of symptoms are examined, including positive and negative reinforcement. The relationships between trichotillomania, other body-focused repetitive behaviours, and disorders of the putative obsessive-compulsive (OC) spectrum are surveyed. The review then explores findings from the available controlled treatment trials that utilized psychotherapy, pharmacotherapy, or both. Neural circuitry involved in the manifestation of hair pulling is then identified by considering data from animal models of the condition, along with neurocognitive and neuroimaging results from patients. Finally, we highlight important areas for future neurobiological and treatment research.

The relationship between recreational gambling and substance abuse/dependence: data from a nationally representative sample

BACKGROUND

Although recreational gambling is prevalent and co-occurs with substance abuse/dependence, few studies have investigated the relationship between the two.

METHODS

Logistic regression analyses were performed on data from a nationally representative sample from the Gambling Impact and Behavior Study.

RESULTS

Substance-abusing recreational gamblers, as compared to non-substance-abusing ones, differed in gambling motivations, began gambling at earlier ages, reported heavier gambling, and preferred and performed strategic forms of gambling.

CONCLUSIONS

As compared with non-substance-abusing gamblers, substance-abusing gamblers demonstrated different gambling profiles including heavier gambling. These findings suggest the need for additional research on whether and how substance use might promote gambling and vice versa.

Impulsivity and response inhibition in alcohol dependence and problem gambling

INTRODUCTION

Impulsivity is a central feature of drug addiction and may arise as a result of impaired inhibitory control. The extent to which inhibitory deficits arise as a consequence of drug exposure or relate to pre-existing addiction vulnerability is unknown.

MATERIALS AND METHODS

This study compared measures of impulsivity in outpatients with alcohol dependence (n = 23) and problem gambling (n = 21), a putative behavioural addiction where direct effects of drug exposure may be minimal. Healthy controls (n = 27) were also tested, in a cross-sectional design. Subjects completed the stop-signal test as a neurocognitive probe of response inhibition, alongside self-report ratings of impulsivity, adult ADHD and OCD.

RESULTS

On the stop-signal test, Go reaction time and stop-signal reaction time were significantly slower in the alcohol-dependent group, compared with healthy controls. Healthy controls slowed their responding after successful and failed stop trials. Slowing after failed stop trials was significantly attenuated in the alcohol-dependent subjects. Go reaction time and post-error slowing were correlated with chronicity and severity, respectively, in the alcohol-dependent subjects. Problem gamblers did not differ significantly from controls on the stop-signal test, despite trait elevations in impulsivity ratings.

CONCLUSION

Inhibitory control is impaired in alcohol dependence but occurs in the context of psychomotor slowing. In addition, alcohol-dependent individuals failed to show behavioral adjustment following failed stops. These deficits may represent direct effects of chronic alcohol administration on fronto-striatal circuitry.

The role of impulsive behavior in drug abuse

BACKGROUND

Impulsivity is a multifaceted construct that has recently been recognized as a factor contributing to enhanced vulnerability to drug abuse.

OBJECTIVES

In the present review, we focus on two facets of impulsivity (and tasks that measure them): (1) impulsive choice (delay discounting task) and (2) inhibitory failure (go/no-go, stop signal reaction time, and five-choice serial reaction time tasks). We also describe how performance on each of these tasks is associated with drug-related behavior during phases of drug abuse that capture the essential features of addiction (acquisition, escalation, and reinstatement of drug-seeking after drug access has terminated). Three hypotheses (H) regarding the relationship between impulsivity and drug abuse are discussed: (1) increased levels of impulsivity lead to drug abuse (H1), (2) drugs of abuse increase impulsivity (H2), and (3) impulsivity and drug abuse are associated through a common third factor (H3).

CONCLUSION

Impulsivity expressed as impulsive choice or inhibitory failure plays a role in several key transition phases of drug abuse. There is evidence to support all three nonexclusive hypotheses. Increased levels of impulsivity lead to acquisition of drug abuse (H1) and subsequent escalation or dysregulation of drug intake. Drugs of abuse may increase impulsivity (H2), which is an additional contributor to escalation/dysregulation. Abstinence, relapse, and treatment may be influenced by both H1 and H2. In addition, there is a relationship between impulsivity and other drug abuse vulnerability factors, such as sex, hormonal status, reactivity to nondrug rewards, and early environmental experiences that may impact drug intake during all phases of addiction (H3). Relating drug abuse and impulsivity in phases of addiction via these three hypotheses provides a heuristic model from which future experimental questions can be addressed.

The diagnosis and treatment of individuals with mental illness and developmental disabilities: an overview

BACKGROUND

The assessment and treatment psychiatric disorders among individuals with developmental disorders is in a state of flux. Clinicians working in this field confront two heterogeneous conditions based on separate but overlapping biopsychosocial bodies of scientific and clinical experiences.

METHODS

The paper is a review of the relevant literature and an effort to synthesize sokme of the major problem areas in differential diagnosis and treatment planning.

RESULTS

There are many genetic, metabolic and neurobehavioral factors that influence both challenging behaviors and the emergence, recognition, and clinical course of mental disorders in people with developmental disorders. As such, clinicians need to redefine dichotomous thinking about boundaries between psychiatrics, neurologic, and behavioral disorders and therapies.

DISCUSSION

Even though there are efforts to adapt our various systems of nomenclature for individuals with developmental disorders, most still rely on descriptive and categorical models. It may be time to reconsider models that incorporate etiological factors in the process of differential diagnosis and classification. By doing so, clinicians may enhance their capacity to match individuals with more finely tuned treatment plans.

Drug Insight: impulse control disorders and dopamine therapies in Parkinson's disease

Impulse control disorders (ICDs) constitute a group of relatively common psychiatric conditions. ICDs typically involve pleasurable or hedonic behaviors (e.g. gambling, shopping or sex) that are performed repetitively, excessively or compulsively, to an extent that interferes in major areas of life functioning. Over the past decade, case reports, case studies and controlled examinations have reported ICDs in neurological patients, particularly those with Parkinson's disease (PD). A relationship between dopamine agonist treatment and ICDs was initially suggested on the basis of clinical observations, and subsequent systematic studies have provided more-substantial support for this association. Ongoing studies of the clinical characteristics of individuals with PD with and without ICDs suggest that certain individuals might be at increased risk of developing ICDs during PD treatment. Emerging data suggest that the association between dopamine agonists and ICDs extends into other neurological patient populations in which these agents are employed, such as those with restless legs syndrome. In this article, we summarize current knowledge regarding ICDs, review their relationships with PD and its treatments, provide practical clinical recommendations based on existing data, and suggest avenues for future research directed at advancing clinical care strategies.

Clinical characteristics and medical complications of pathologic skin picking

OBJECTIVE

This study sought to detail the phenomenology and medical consequences of pathologic skin picking (PSP).

METHOD

Sixty subjects (11.7% males) with PSP (mean+/-S.D.=33.7+/-11.6 years) were assessed. Subjects seen in a pharmacological study as well as those from an ongoing outpatient longitudinal study comprised this sample. Subjects were assessed for current and lifetime psychiatric comorbidity (using the Structured Clinical Interview for DSM-IV Axis I Disorders), clinical severity (using the Clinical Global Impression - Severity scale) and psychosocial interference due to picking (using the Sheehan Disability Scale). Clinical characteristic data, including time spent picking per day, sites picked and medical complications directly resulting from skin picking behavior, as well as family history, were also obtained.

RESULTS

The mean age (+/-S.D.) of onset for PSP was 12.3+/-9.6 years. The face was the most common area picked. Subjects reported picking a mean of 107.6 min each day. Scarring, ulcerations and infections were common. Few had ever sought psychiatric treatment for their behavior. Current comorbid Axis I psychiatric conditions were found in 38.3% of the sample. Trichotillomania (36.7%), compulsive nail biting (26.7%), depressive disorder (16.7%) and obsessive-compulsive disorder (15%) were the most common current comorbid conditions.

CONCLUSION

PSP appears to be time consuming and frequently associated with medical complications. Research is needed to optimize patient care for individuals with this behavior.

Repetitive love proposing: A case report and review of phenomenology of impulsivity and compulsivity

Interest in opposite sex is a normal phenomenon; however, when this interest starts affecting one's own or others life in a pathological manner, it warrants clinical attention. We report the case of a young man who had a tendency to propose love to girls impulsively. Apart from the presence of this, otherwise, normal behavior in a pathological manner, another dimension of this case was that he was having obsessive-compulsive disorder too. Since both impulsivity and compulsivity are repetitive in nature and result in a sense of relief when the act is committed, the chance of impulsivity to be misconstrued as compulsivity is high. In light of important differences between compulsive and impulsive behavior, the psychopathology of the present case has been discussed.

N-acetyl cysteine, a glutamate-modulating agent, in the treatment of pathological gambling: a pilot study

BACKGROUND

Although pathological gambling (PG) is relatively common, pharmacotherapy research for PG is limited. N-acetyl cysteine (NAC), an amino acid, seems to restore extracellular glutamate concentration in the nucleus accumbens and therefore offers promise in reducing addictive behavior.

METHODS

Twenty-seven subjects (12 women) with DSM-IV PG were treated in an 8-week open-label trial of NAC with responders (defined as a > or = 30% reduction in Yale Brown Obsessive Compulsive Scale Modified for Pathological Gambling [PG-YBOCS] total score at end point) randomized to 6 weeks of double-blind NAC or placebo.

RESULTS

The PG-YBOCS scores decreased from a mean of 20.3 +/- 4.1 at baseline to 11.8 +/- 9.8 at the end of the open-label phase (p < .001). Sixteen of 27 subjects (59.3%) met responder criteria. The mean effective dose of NAC was 1476.9 +/- 311.3 mg/day. Of 16 responders, 13 entered the double-blind phase. Of those assigned to NAC, 83.3% still met responder criteria at the end of the double-blind phase, compared with only 28.6% of those assigned to placebo.

CONCLUSIONS

The efficacy of NAC lends support to the hypothesis that pharmacological manipulation of the glutamate system might target core symptoms of reward-seeking addictive behaviors such as gambling. Larger, longer, placebo-controlled double-blind studies are warranted.

Recent Advances in the Understanding and Treatment of Anxiety Disorders

Anxiety disorders usually are chronic or recurrent disorders characterized by stress sensitivity and a fluctuating course. Both psychopharmacologic and cognitive-behavioral treatments are well-established, evidence-based treatments for panic disorder, social anxiety disorder, generalized anxiety disorder, and obsessive-compulsive disorder. Exposure-based behavioral treatment is well established as evidence-based treatment for specific phobias. Primary care physicians can make a significant impact on patients' lives by identifying and educating about anxiety disorders, directing patients to appropriate self-help resources, choosing evidence-based drug treatment when indicated, and making referrals for specialist care.

The neurobiology and genetics of impulse control disorders: relationships to drug addictions

Impulse control disorders (ICDs), including pathological gambling, trichotillomania, kleptomania and others, have been conceptualized to lie along an impulsive-compulsive spectrum. Recent data have suggested that these disorders may be considered addictions. Here, we review the genetic and neuropathological bases of the impulse control disorders and consider the disorders within these non-mutually exclusive frameworks.

Neuropsychological functioning in kleptomania

Kleptomania is characterized by the failure to resist impulses to steal objects not needed for personal use or their monetary value. The objective of this study was to examine cognitive and executive functioning in subjects with kleptomania. Fifteen women with a primary DSM-IV diagnosis of kleptomania underwent a detailed psychiatric examination, including measures of kleptomania severity, and a battery of neuropsychological tests that emphasized executive functions. Correlational analyses were computed between measures of kleptomania severity and tests of executive functioning. Kleptomania subjects reported a mean duration of illness of 17.9 years and shoplifting a mean of 1.7 times per week. All subjects reported an inability to resist urges to shoplift. Neuropsychological testing revealed group mean test scores within 0.5 standard deviations of normative standards for age. Five subjects (33.3%), however, had below-average performance on at least one measure of executive functioning, and 4 (26.7%) had below-average scores on two executive measures. Correlational analyses revealed a statistically significant correlation between kleptomania severity and Wisconsin Card Sorting Test performance (r=-0.693, p=0.004). As a group, subjects with kleptomania did not demonstrate deficits on neuropsychological testing. Greater kleptomania symptom severity, however, was correlated with impairment in executive functioning.

Medication management of pathological gambling

Pathological gambling has received little attention from clinicians and researchers despite prevalence rates similar to or greater than those of schizophrenia and bipolar disorder. This article summarizes the phenomenology and associated psychopathology of this public health problem and presents results of studies of 3 types of pharmacological agents used to treat this disorder: serotonin reuptake inhibitors, opioid antagonists, and mood stabilizers.