Understanding the differences between impulsivity and compulsivity

• Published in: The Psychiatric times 2008-07, Vol.25 (8), p.58
• Main Authors: Berlin, Heather A, Hollander, Eric
• Format: Article
• Language: English
• Subjects: Behavior; Clinical outcomes; Drugs; Fashion models; Gambling; Genetic aspects; Mental illness; Neurosciences
• ISSN: 0893-2905

Objective neurocognitive tests hold potential for elucidating the mechanisms by which pharmacological agents exert their beneficial clinical effects and for predicting clinical outcomes.5,6 Using sensitive and domain-specific neurocognitive tasks, we may also be able to divide impulsivity and compulsivity into separate and quantifiable neurobiologically specific domains.7 Disorders characterized by impulsivity include impulse control disorders in DSM-IV-TR, representing a failure to resist aggressive impulses (as in intermittent explosive disorder) and urges to steal (kleptomania), set fires (pyromania), gamble (pathological gambling), and pull one's hair (trichotillomania). [...] decreased frontal lobe activity may characterize the impulsive disorders, such as pathological gambling and borderline personality disorder.9 Impulsive and compulsive features may present at the same time or at different times during the same illness.\n Depending on a mix of these factors, certain drugs may need to be avoided, nonstandard drug combinations may be needed, or safer but less effective drugs may need to replace more effective drugs whose abuse by suicidal patients may have more dangerous consequences.38 OCD is heterogeneous in terms of types of obsessions and compulsions, heritability, and comorbid conditions, which probably reflect heterogeneity in the underlying pathology.18 Accordingly, there are many disorders known as obsessivecompulsive spectrum disorders that share features with OCD, including trichotillomania and body dysmorphic disorder.39,40 The apparent association between altered serotonergic function and OCD has guided attention toward the possible role of serotonergic function in the underlying cause of trichotillomania.41 Some investigators have postulated that patients with trichotillomania who engage primarily in hair pulling, where their attention is focused on the hair pulling, are more phenomenologically similar to individuals with compulsions in OCD than those with automatic hair pulling that occurs outside conscious awareness, and thus they may be more responsive to pharmacological interventions found to be effective for OCD.42,43 A number of investigations of the use of antidepressants with specific inhibition of serotonin reuptake (ie, fluoxetine and clomipramine) have yielded mixed results. 44-48 Naltrexone, an opioid antagonist, has been found to be superior to placebo in reducing trichotillomania symptoms.49 Also, augmentation of SSRIs with