Trait impulsivity as an endophenotype for bipolar I disorder

Abstract

Objective Impulsivity, conceptualized as impairment in planning and poor attentional and inhibitory control, is a key feature of bipolar disorder. Familial risk for bipolar disorder is known to affect inhibitory control but its impact on the attentional and planning dimensions of impulsivity is still unclear. Methods We administered the Barratt Impulsiveness Scale, version 11 (BIS-11) to 54 euthymic individuals with DSM–IV bipolar I disorder, 57 of their clinically unaffected siblings, and 49 healthy comparison subjects. Groups were compared on the attentional (rapid shifts in attention/impatience with complexity), motor (acting impetuously), and non-planning (absence of weighing upon long-term consequences of actions) subscales of the BIS-11, and on total BIS-11 score. To investigate functional implications of trait impulsivity, total BIS-11 score was examined in relation to current psychosocial functioning and criminal history. Results Individuals with bipolar I disorder had elevated scores compared to healthy comparison subjects on BIS-11 total score and all three subscales (p < 0.0001). Unaffected siblings had elevated BIS-11 total score (p = 0.0037), motor (p = 0.0027), and non-planning (p = 0.0379) subscales in comparison to unrelated healthy controls. Total BIS-11 score was negatively associated with global assessment of functioning (GAF) score (β = −0.32, p < 0.0001). Conclusions Our results suggest that impulsivity is sensitive to familial liability for the illness, making it a potential endophenotype for bipolar disorder.

Impulsivity and Risk Taking in Bipolar Disorder and Schizophrenia

“…These inconsistencies in past research (eg, Holmes et al, 2009;Lombardo et al, 2012) might be explained if previous studies had different proportions of patients on and off AP medications, or were limited in testing these effects because of small sample sizes.…”

“…Although risky-impulsive behavior is a diagnostic criterion for mania (American Psychiatric Association, 2000) and bipolar patients consistently show abnormalities on selfreport measures of impulsivity, they do not consistently show deficits on behavioral tasks that require planning and forethought (Holmes et al, 2009;Lombardo et al, 2012). These differences may reflect the multi-faceted nature of impulsivity (Dalley and Roiser, 2012), or the measurement tools used to assess the construct (Ouzir, 2013).…”

“…; Lombardo et al, 2012). Furthermore, behavioral performance on measures of impulsivity varies in euthymic BP patients: one study found increased impulsivity only in bipolar patients with co-occurring alcohol use disorders (Holmes et al, 2009), and another found behavioral task impulsivity not to be elevated in euthymic patients (Swann et al, 2003).…”

Multidimensional assessment of impulsivity in schizophrenia, bipolar disorder, and major depressive disorder: testing for shared endophenotypes

“…Response inhibition and executive functioning tasks have been shown in some studies to be impaired in relatives of individuals with BD relative to HCs (Bora et al 2009), although Ethridge et al (2014) found no response inhibition deficit in first-degree relatives. Self-reported impulsivity is also elevated in siblings of BD probands (Lombardo et al 2012). Impulsive aggression has also been named a potential endophenotype for suicidal behavior (Mann et al 2009;McGirr et al 2009), but impulsivity has not been considered an endophenotype for MDD more broadly.…”

Variants in Ion Channel Genes Link Phenotypic Features of Bipolar Illness to Specific Neurobiological Process Domains

“…Clinical studies using the Barratt Impulsiveness Scale (BIS) have shown that impulsivity is present not only during affective states but also in the euthymic state [62,63], and that it also occurs in unaffected siblings [64]. Lombardo et al [64] studied impulsivity using the BIS-11 in euthymic bipolar patients, unaffected relatives, and healthy controls. The BIS-11 scores were higher in unaffected relatives during motor and nonplanning tasks than in controls.…”