Impulsivity across the course of bipolar disorder

Explicit and implicit reinforcement learning across the psychosis spectrum

Motivational and hedonic impairments are core features of a variety of types of psychopathology. An important aspect of motivational function is reinforcement learning (RL), including implicit (i.e., outside of conscious awareness) and explicit (i.e., including explicit representations about potential reward associations) learning, as well as both positive reinforcement (learning about actions that lead to reward) and punishment (learning to avoid actions that lead to loss). Here we present data from paradigms designed to assess both positive and negative components of both implicit and explicit RL, examine performance on each of these tasks among individuals with schizophrenia, schizoaffective disorder, and bipolar disorder with psychosis, and examine their relative relationships to specific symptom domains transdiagnostically. None of the diagnostic groups differed significantly from controls on the implicit RL tasks in either bias toward a rewarded response or bias away from a punished response. However, on the explicit RL task, both the individuals with schizophrenia and schizoaffective disorder performed significantly worse than controls, but the individuals with bipolar did not. Worse performance on the explicit RL task, but not the implicit RL task, was related to worse motivation and pleasure symptoms across all diagnostic categories. Performance on explicit RL, but not implicit RL, was related to working memory, which accounted for some of the diagnostic group differences. However, working memory did not account for the relationship of explicit RL to motivation and pleasure symptoms. These findings suggest transdiagnostic relationships across the spectrum of psychotic disorders between motivation and pleasure impairments and explicit RL. (PsycINFO Database Record

Suicidality in Bipolar Disorder: The Role of Emotion-Triggered Impulsivity

A growing body of research suggests that impulsive responses to emotion more robustly predict suicidality than do other forms of impulsivity. This issue has not yet been examined within bipolar disorder, however. Participants diagnosed with bipolar I disorder (n = 133) and control participants (n = 110) diagnosed with no mood or psychotic disorder completed self-report measures of emotion-triggered impulsivity (Negative and Positive Urgency Scales) and interviews concerning lifetime suicidality. Analyses examined the effects of emotion-triggered impulsivity alone and in combination with gender, age of onset, depression severity, comorbid anxiety, comorbid substance use, and medication. A history of suicide ideation and attempts, as well as self-harm, were significantly more common in the bipolar disorder group compared with the control group. Impulsive responses to positive emotions related to suicide ideation, attempts, and self-harm within the bipolar group. Findings extend research on the importance of emotion-triggered impulsivity to a broad range of key outcomes within bipolar disorder. The discussion focuses on limitations and potential clinical implications.

Behavioral and Electrophysiological Alterations for Reinforcement Learning in Manic and Euthymic Patients with Bipolar Disorder

AIMS

Bipolar disorder is characterized by behavioral changes such as risk-taking and increasing goal-directed activities, which may result from altered reward processing. Patients with bipolar disorder show impaired reward learning in situations that require the integration of reinforced feedback over time. In this study, we examined the behavioral and electrophysiological characteristics of reward learning in manic and euthymic patients with bipolar disorder using a probabilistic reward task.

METHODS

Twenty-four manic and 20 euthymic patients with bipolar I disorder and 24 healthy control subjects performed the probabilistic reward task. We assessed response bias (RB) as a preference for the stimulus paired with the more frequent reward and feedback-related negativity (FRN) to correct identification of the rich stimulus.

RESULTS

Both manic and euthymic patients showed significantly lower RB scores in the early learning stage (block 1) in comparison with the late learning stage (block 2 or block 3) of the task, as well as significantly lower RB scores in the early stage compared to healthy subjects. Relatively more negative FRN amplitude is elicited by no presentation of an expected reward, compared to that elicited by presentation of expected feedback. The FRN became significantly more negative from the early (block 1) to the later stages (blocks 2 and 3) in both manic and euthymic patients, but not in healthy subjects. Changes in RB scores and FRN amplitudes between blocks 2 and 3 and block 1 correlated positively in healthy controls, but correlated negatively in manic and euthymic patients. The severity of manic symptoms correlated positively with reward learning scores and negatively with the FRN.

CONCLUSIONS

These findings suggest that patients with bipolar disorder during euthymic or manic states have behavioral and electrophysiological alterations in reward learning compared to healthy subjects. This dysfunctional reward processing may be related to the abnormal decision-making or altered goal-directed activities frequently seen in patients with bipolar disorder.

Delay of Gratification in Predicting Job Performance in New Employees: A Time-Varying Process and the Moderating Role of Perceived Informational Justice

Our study profiles a varying process of the relationship between delay of gratification (DG) and job performance over time and examines the moderating role of perceived organisational justice in the DG-job performance relationship. Employees’ ability to delay gratification was measured during their job interviews (Time 1). When they had worked for 3 months (Time 2), their job performance was rated by their supervisors. When they had worked for 5 months (Time 3), their perception of perceived informational justice was measured. Their job performance was rated again by their supervisors at 6 months (Time 4). The results showed that DG could directly predict new employees’ short-term (3-month) job performance but not their longer-term (6-month) job performance. Moreover, perceived informational justice moderated the relationship between DG and 6-month job performance.

Comparisons of Subthreshold Versus Full Posttraumatic Stress Disorder Distinguished by Subjective Functional Impairment Among Train Drivers: A Population-Based Nationwide Study in South Korea

OBJECTIVE

Subthreshold posttraumatic stress disorder (SPTSD), a condition that meets the full symptomatic criteria of posttraumatic stress disorder (PTSD) without subjective functional impairment, has yet to be fully investigated. In this study, we aimed to determine the prevalence and characteristics of SPTSD.

METHODS

The web-based survey including psychiatric diagnosis and experience of human error was conducted in actively working train drivers in South Korea.

RESULTS

Of the 4,634 subjects, 103 (2.23%) were categorized as full PTSD and 322 (6.96%) were categorized as having SPTSD. Individuals with full PTSD showed higher impulsivity and anxiety compared to those with SPTSD and those without PTSD, while those with SPTSD had more frequent clinically meaningful depression, posttraumatic stress, and alcohol and nicotine dependence and significant human error.

CONCLUSION

Despite not qualifying as a subjective functional disability, SPTSD still had significant psychiatric symptoms. More clinical attentions need to be given to the diagnosis and treatment of SPTSD.

Magnitude and associated factors of aggressive behaviour among patients with bipolar disorder at Amanual Mental Specialized Hospital, outpatient department, Addis Ababa, Ethiopia: cross-sectional study

BACKGROUND

Aggressive behavior is a challenging behavior among bipolar patients that causes poor social interaction and hospitalization. But, there is no information regards of the magnitude and contributing factors for aggressive behaviour among bipolar patients in Ethiopia. Therefore, this study was designed to assess the prevalence and associated factors of aggressive behaviour among patients with bipolar disorder.

METHOD

An institutional based cross sectional study was conducted at Amanual Mental Specialized Hospital from May 1 to June 1, 2015 among 411 participants who were selected by systematic random sampling technique. Data was collected by interview technique by using Modified Overt Aggression Scale, entered and analyzed by using Epi Data 3.1 and Statistical Package for Social Science version 20, respectively. Adjusted Odd Ratio (AOR) with 95% Confidence Interval (CI) were used to show the odd and P-value <0.05 was considered as statistically significant.

RESULTS

A total of 411 bipolar patients were included in the study and the prevalence of aggressive behaviour was 29.4%. Significant associated factors for aggression were, having two or more episode [AOR = 2.35 95% CI (1.18, 4.69)], previous history of aggression, [AOR = 3.72, 95% CI (1.54, 8.98)], depressive symptoms [AOR = 3.63, 95% CI (1.89, 6.96)], psychotic symptoms [AOR = 5.41,95% CI (2.88, 10.1)], manic symptoms [AOR = 3.85,95% CI (2.06, 7.19)], poor medication adherence [AOR = 3.73 95% CI (1.71, 8.13)], poor social support [AOR = 2.99 95% CI (1.30, 6.91)] and current use of substance[AOR = 2.17 95% CI (1.16, 4.06)].

CONCLUSION

Prevalence of aggression is high among bipolar patients and associated with many factors. So it needs public health attention to decrease aggression among bipolar patients.

Behavioral measures and self-report of impulsivity in bipolar disorder: no association between Stroop test and Barratt Impulsiveness Scale

BACKGROUND

Impulsivity as a tendency to act quickly without considering future consequences has been proposed as a dimensional factor in bipolar disorder. It can be measured using behavioral tasks and self-report questionnaires. Previous findings revealed patients to show worse performance on at least one behavioral measure of impulsivity. Additionally, self-reported impulsivity seems to be higher among bipolar patients, both parameters being possibly associated with a more severe course of illness. In this study, our primary aim was to investigate the relationship between these two constructs of impulsivity among bipolar patients.

METHODS

A total of 40 euthymic patients with bipolar disorder (21 female, 22 Bipolar I) and 30 healthy controls were recruited for comprehensive neuropsychological assessment. To assess inhibition control as a behavioral measure of impulsivity, the Stroop Color and Word Test (Stroop) was used. Additionally, both groups completed the Barratt Impulsiveness Scale (BIS) as a self-report of impulsivity. To compare the groups' performance on the Stroop and ratings on the BIS, the non-parametric Mann-Whitney U test was used. Within the bipolar group, we additionally examined the possibility of an association between Stroop performance and BIS total scores using Pearson's Correlation r.

RESULTS

Patients and controls differed significantly on the Stroop and BIS, with patients performing worse on the Stroop and scoring higher on the BIS. However, there was no association between the Stroop and BIS within the bipolar group. As an exploratory analysis, a positive correlation between Stroop performance and number of episodes was found. Further, we detected a statistical trend in the direction of poorer Stroop performance among patients treated with polypharmacy.

CONCLUSIONS

Both difficulties with behavioral inhibition and self-reported impulsivity were observed to be higher in bipolar patients than controls in the current study. However, within the patient group we did not observe an association between patients' behavioral performance and self-report. This indicates that the parameters likely constitute distinct, dimensional factors of bipolar disorder. In future research, studies with larger samples should investigate which of the two markers constitutes the better marker for the illness and is more suitable to differentiate the most severe patients.

Differences in Real World Executive Function between Children with Pediatric Bipolar Disorder and Children with ADHD

BACKGROUND

Recent research evidence suggests that executive function (EF) is impaired in both pediatric bipolar disorder (PBD) and attention deficit-hyperactivity disorder (ADHD), although the underlying cognitive mechanisms are still unclear. In this study we examined EF, including cognitive and emotional control, in three pediatric groups with overlapping symptoms.

METHODS

Sixteen children and adolescents with PBD, 17 children and adolescents with ADHD, Type Combined, and 13 children and adolescents with PBD and comorbid ADHD (PBD+ADHD) (mean age=12.70, SD=2.21) were assessed using the Behavioral Rating Inventory of Executive Function - Parental Report (BRIEF-PR), clinical scales and neuropsychological tests of attention, working memory and executive function.

RESULTS

All groups showed impairment on the Trails A and B tests. However, there were no significant group differences. On the BRIEF-PR while all three groups were impaired in General Executive Functioning and Metacognition only the two PBD groups revealed more extensive EF dysfunction, in both cognitive and emotional control domains, relative to the ADHD group. Conversely, the ADHD group exhibited selective deficits in cognitive domains such as working memory, planning/organization, monitoring, and metacognition. The two PBD groups showed greater impairment than the ADHD group in the domains of Inhibition, Shifting, Monitoring and Emotional Control. Furthermore, results from regression analyses suggest cognitive predictors of EF impairment in ADHD and mood predictors for inhibition in PBD.

CONCLUSIONS

The current results contribute new knowledge on domain-specific similarities and differences in executive dysfunction between PBD, ADHD, and the comorbid phenotype, which may inform the diagnostic process and cognitive intervention.

Neurofunctional Differences Among Youth With and at Varying Risk for Developing Mania

OBJECTIVE

To examine prefrontal and amygdala activation during emotional processing in youth with or at varying risk for developing mania to identify candidate central prodromal risk biomarkers.

METHOD

Four groups of medication-free adolescents (10-20 years old) participated: adolescents with first-episode bipolar I disorder (BP-I; n = 32), adolescents with a parent with bipolar disorder and a depressive disorder (at-risk depressed [ARD]; n = 32), healthy adolescents with a parent with bipolar disorder (at-risk healthy [ARH]; n = 32), and healthy adolescents with no personal or family history of psychiatric illness (healthy comparison [HC]; n = 32). Participants underwent functional magnetic resonance imaging while performing a continuous performance task with emotional and neutral distracters. Region-of-interest analyses were performed for the bilateral amygdala and for subregions of the ventrolateral prefrontal cortex and anterior cingulate cortex.

RESULTS

Overall, no group differences in bilateral amygdala and ventrolateral prefrontal cortex (Brodmann area [BA] 45/47) activation during emotional or neutral stimuli were observed. The BP-I group exhibited lower right pregenual anterior cingulate cortex activation compared with the HC group, and activation in the left BA 44 was greater in the ARH and ARD groups compared with the HC group. BP-I and ARD groups exhibited blunted activation in the right BA 10 compared with the ARH group.

CONCLUSION

During emotional processing, amygdala and ventrolateral prefrontal cortex (BA 45/47) activation does not differ in youth with or at increasing risk for BP-I. However, blunted pregenual anterior cingulate cortex activation in first-episode mania could represent an illness biomarker, and greater prefrontal BA 10 and BA 44 activations in at-risk youth could represent a biomarker of risk or resilience warranting additional investigation in prospective longitudinal studies.

Emotional dysregulation in those with bipolar disorder, borderline personality disorder and their comorbid expression

BACKGROUND

Differentiation of the bipolar disorders (BP) from a borderline personality disorder (BPD) can be challenging owing to shared features, with emotional dysregulation being the likely principal one.

AIM

To assess differences in emotion regulation strategies in those with BP alone, BPD alone and those comorbid for both.

METHODS

We interviewed participants previously receiving a BP or BPD diagnosis, studying those who met DSM criteria for one or both conditions.

RESULTS

The sample comprised 83 with bipolar disorder, 53 with BPD and 54 comorbid for both. Analyses established linear trends, with the greatest impairment in emotion regulation strategies in the comorbid group followed by the BPD group, and with the lowest in the BP group. Specific deficits in the comorbid group included impulsivity, difficulties with goal directed behaviour, and accessing strategies. A similar linear profile was quantified for maladaptive cognitive emotion regulation strategies, weighted to catastrophizing and rumination. Adaptive emotion regulation strategies were superior in the bipolar group, without significant differences observed between the comorbid and BPD groups.

LIMITATIONS

Reliance on self-report measures; combined BP I and II participants limits generalisability of results to each bipolar sub-type; use of DSM diagnoses risking artefactual comorbidity; while there was an over-representation of females in all groups.

CONCLUSIONS

Differences in emotion regulation strategies advance differentiation of those with either BP or BPD, while we identify the specificity of differing strategies to each condition and their synergic effect in those comorbid for both conditions. Study findings should assist the development and application of targeted strategies for those with either or both conditions.

Investigating the Impact of a Genome-Wide Supported Bipolar Risk Variant of MAD1L1 on the Human Reward System

Recent genome-wide association studies have identified MAD1L1 (mitotic arrest deficient-like 1) as a susceptibility gene for bipolar disorder and schizophrenia. The minor allele of the single-nucleotide polymorphism (SNP) rs11764590 in MAD1L1 was associated with bipolar disorder. Both diseases, bipolar disorder and schizophrenia, are linked to functional alterations in the reward system. We aimed at investigating possible effects of the MAD1L1 rs11764590 risk allele on reward systems functioning in healthy adults. A large homogenous sample of 224 young (aged 18-31 years) participants was genotyped and underwent functional magnetic resonance imaging (fMRI). All participants performed the 'Desire-Reason Dilemma' paradigm investigating the neural correlates that underlie reward processing and active reward dismissal in favor of a long-term goal. We found significant hypoactivations of the ventral tegmental area (VTA), the bilateral striatum and bilateral frontal and parietal cortices in response to conditioned reward stimuli in the risk allele carriers compared with major allele carriers. In the dilemma situation, functional connectivity between prefrontal brain regions and the ventral striatum was significantly diminished in the risk allele carriers. Healthy risk allele carriers showed a significant deficit of their bottom-up response to conditioned reward stimuli in the bilateral VTA and striatum. Furthermore, functional connectivity between the ventral striatum and prefrontal areas exerting top-down control on the mesolimbic reward system was reduced in this group. Similar alterations in reward processing and disturbances of prefrontal control mechanisms on mesolimbic brain circuits have also been reported in bipolar disorder and schizophrenia. Together, these findings suggest the existence of an intermediate phenotype associated with MAD1L1.

Impulsivity predicts the onset of DSM-IV-TR or RDC hypomanic and manic episodes in adolescents and young adults with high or moderate reward sensitivity

BACKGROUND

A growing body of research suggests that bipolar disorders (BD) are associated with high impulsivity. Using a multi-method approach, the current study provided the first examination of the hypothesis that impulsivity would prospectively predict shorter time to onset of DSM-IV-TR or RDC hypomanic or manic episodes in a sample selected based on reward sensitivity, a biobehavioral trait shown to predict onset and course of BD.

METHODS

163 participants with high reward sensitivity and 114 participants with moderate reward sensitivity were followed every six months for an average of 2.68 years. Participants completed the Barratt Impulsiveness Scale - Version 11 (BIS-11), Balloon Analog Risk Task (BART), Beck Depression Inventory, Altman Self-Rating Mania Scale, and an expanded Schedule for Affective Disorders and Schizophrenia (exp-SADS) - Lifetime Version at baseline and were followed prospectively with the exp-SADS - Change Version to assess onset of hypomanic or manic episodes and treatment seeking for mood problems.

RESULTS

Cox proportional hazard regression analyses indicated that impulsivity as measured by a behavioral task (BART; OR=1.04, p=.03) and a self-report measure (BIS-11 Attentional Impulsiveness subscale; OR=1.16, p=.01) predicted shorter time to hypomania/mania onset, after controlling for baseline depressive and manic symptoms, family history of mood disorder, treatment seeking for mood problems, and reward sensitivity.

LIMITATIONS

The study was limited by non-comprehensive assessment of impulsivity and unknown generalizability to clinical samples.

CONCLUSIONS

Impulsivity confers vulnerability to hypomania or mania. Future studies would benefit from considering how impulsivity can be integrated into existing biopsychosocial models of BD.

Decision-making in patients with temporal lobe epilepsy: Delay gratification ability is not impaired in patients with hippocampal sclerosis

BACKGROUND

Decision-making abilities have rarely been examined in patients with temporal lobe epilepsy related to hippocampal sclerosis (TLE-HS). We aimed to investigate the ability to delay gratification, a decision-making subdomain, in patients with intractable TLE-HS and to verify the association of delay gratification performance and cool executive function tests.

METHODS

We evaluated 27 patients with TLE-HS (mean age: 35.46 [±13.31] years; 7 males) and their cognitive performance was compared with that of 27 age- and gender-matched healthy controls (mean age: 35.33 [±12.05] years; 7 males), without epilepsy and psychiatric disorders. Patients were assessed using the delay discounting task (DDT) and tests of attention, shifting, inhibitory control, and concept formation. Results were correlated with clinical epilepsy variables such as age of onset, epilepsy duration, AED use, history of status epilepticus, febrile seizures, and the presence of generalized seizures. Statistical analysis was performed using one-way ANCOVA with years of education as a confounding factor.

RESULTS

Patients and controls demonstrated similar performance on DDT, showing similar discount rate (p=0.935) and probability rate (p=0.585). Delay gratification was not related to cool executive function tests (Digit Span, Stroop Color Test, Trail Making Test, Wisconsin Card Sorting Test, and Connors' CPT). History of status epilepticus, presence of generalized seizures and higher seizure frequency, age at onset, and epilepsy duration had a significant impact on DDT.

CONCLUSION

Patients with intractable TLE-HS showed unimpaired delay gratification abilities, being able to accept a higher delay and a lower amount of chance for receiving a higher reward in the future. Clinical variables related to the epilepsy severity impacted the performance on delay gratification. Impairment on cool aspects of executive function was unrelated to this decision-making domain.

Assessing personal financial management in patients with bipolar disorder and its relation to impulsivity and response inhibition

INTRODUCTION

Impulsivity and risk-taking behaviours are reported in bipolar disorder (BD). We examined whether financial management skills are related to impulsivity in patients with BD.

METHODS

We assessed financial management skills using the Executive Personal Finance Scale (EPFS), impulsivity using the Barratt Impulsiveness Scale (BIS) and response inhibition using an emotional go/no-go task in bipolar individuals (N = 21) and healthy controls (HC; N = 23).

RESULTS

Patients had fewer financial management skills and higher levels of impulsivity than HC. In patients and controls, increased impulsivity was associated with poorer personal financial management. Patients and HC performed equally on the emotional go/no-go task. Higher BIS scores were associated with faster reaction times in HC. In patients, however, higher BIS scores were associated with slower reaction times, possibly indicating compensatory cognitive strategies to counter increased impulsivity.

CONCLUSIONS

Patients with BD may have reduced abilities to manage personal finances, when compared against healthy participants. Difficulty with personal finance management may arise in part as a result of increased levels of impulsivity. Patients may learn to compensate for increased impulsivity by modulating response times in our experimental situations although whether such compensatory strategies generalize to real-world situations is unknown.

A web-based study of bipolarity and impulsivity in athletes engaging in extreme and high-risk sports

BACKGROUND

We hypothesised that men and women who engage in extreme or high-risk sports would score higher on standardised measures of bipolarity and impulsivity compared to age and gender matched controls.

METHODS

Four-hundred and eighty extreme or high-risk athletes (255 males and 225 females) and 235 age-matched control persons (107 males and 128 females) were enrolled into the web-based case-control study. The Mood Disorder Questionnaire (MDQ) and Barratt Impulsiveness Scale (BIS-11) were administered to screen for bipolarity and impulsive behaviours, respectively.

RESULTS

Results indicated that extreme or high-risk athletes had significantly higher scores of bipolarity and impulsivity, and lower scores on cognitive complexity of the BIS-11, compared to controls. Further, there were positive correlations between the MDQ and BIS-11 scores.

CONCLUSION

These results showed greater rates of bipolarity and impulsivity, in the extreme or high-risk athletes, suggesting these measures are sensitive to high-risk behaviours.

Dysfunctional decision-making related to white matter alterations in bipolar I disorder

OBJECTIVE

This study investigated how frontal white matter (WM) alterations in patients with bipolar I disorder (BD-I) are linked to motivational dysregulation, often reported in the form of risk-taking and impulsivity, and whether structure-function relations in patients might differ from healthy subjects (HC).

METHOD

We acquired diffusion data from 24 euthymic BD-I patients and 24 controls, to evaluate WM integrity of selected frontal tracts. Risk-taking was assessed by the Cambridge Gambling Task and impulsivity by self-report with the Barratt-Impulsiveness Scale.

RESULTS

BD-I patients displayed significantly lower integrity in the right cingulum compared to HC. They also showed more risk-taking behavior and reported increased trait-impulsivity. Risk-taking was negatively associated with WM integrity in the right cingulum. Impulsivity was not related to WM integrity in investigated tracts. Together with age and sex, FA in the cingulum explained 25% of variance in risk-taking scores in all study participants. The left inferior fronto-occipital fasciculus (IFOF) was specifically predictive of risk-taking behavior in BD-I patients, but not in HC.

LIMITATIONS

The employed parameters did not allow us to specify the exact origin of WM changes, nor did the method allow the analysis of specific brain subregions. Also, sample size was moderate and the sample included patients with lifetime alcohol dependence/abuse, hence effects found need replication and have to be interpreted with caution.

CONCLUSION

Our results further strengthen recent models linking structural changes in frontal networks to behavioral markers of BD-I. They extend recent findings by showing that risk-taking is also linked to the cingulum in BD-I and HC, while other prefrontal tracts (IFOF) are specifically implicated in risk-taking behavior in BD-I patients. Meanwhile, self-reported impulsivity was not associated with WM integrity of the tracts investigated in our study.

Response inhibition in the parametric go/no-go task and its relation to impulsivity and subclinical psychopathy

The current study utilizes the parametric go/no-go task (PGNG), a task that examines changes in inhibitory performance as executive function load increases, to examine the link between psychopathic traits, impulsivity, and response inhibition in a cohort of healthy participants. The results show that as executive function load increased, inhibitory ability decreased. High scores on the Cognitive Complexity subscale of the Barratt Impulsivity Scale (BIS-11) predict poor inhibitory ability in the PGNG. Similarly, high scores on the Psychopathy Personality Inventory-Revised (PPI-R) Blame Externalization subscale predict response inhibition deficits in the PGNG, which loads more on the executive functions than the standard go/no-go task. The remaining BIS-11 as well as PPI-R subscales did not interact with inhibitory performance in the PGNG highlighting the specificity of associations between aspects of personality and impulsivity with inhibitory performance as cognitive load is increased. These data point towards the sensitivity of the PGNG in studying response inhibition in the context of highly impulsive populations and its utility as a measure of impulsivity.

Rapid-response impulsivity: definitions, measurement issues, and clinical implications

Impulsivity is a multifaceted construct that is a core feature of multiple psychiatric conditions and personality disorders. However, progress in understanding and treating impulsivity is limited by a lack of precision and consistency in its definition and assessment. Rapid-response impulsivity (RRI) represents a tendency toward immediate action that occurs with diminished forethought and is out of context with the present demands of the environment. Experts from the International Society for Research on Impulsivity (InSRI) met to discuss and evaluate RRI measures in terms of reliability, sensitivity, and validity, with the goal of helping researchers and clinicians make informed decisions about the use and interpretation of findings from RRI measures. Their recommendations are described in this article. Commonly used clinical and preclinical RRI tasks are described, and considerations are provided to guide task selection. Tasks measuring two conceptually and neurobiologically distinct types of RRI, "refraining from action initiation" (RAI) and "stopping an ongoing action" (SOA) are described. RAI and SOA tasks capture distinct aspects of RRI that may relate to distinct clinical outcomes. The InSRI group recommends that (a) selection of RRI measures should be informed by careful consideration of the strengths, limitations, and practical considerations of the available measures; (b) researchers use both RAI and SOA tasks in RRI studies to allow for direct comparison of RRI types and examination of their associations with clinically relevant measures; and (c) similar considerations be made for human and nonhuman studies in an effort to harmonize and integrate preclinical and clinical research.

Impulsivity across the psychosis spectrum: Correlates of cortical volume, suicidal history, and social and global function

Patients with psychotic disorders appear to exhibit greater impulsivity-related behaviors relative to healthy controls. However, the neural underpinning of this impulsivity remains uncertain. Furthermore, it remains unclear how impulsivity might differ or be conserved between psychotic disorder diagnoses in mechanism and manifestation. In this study, self-reported impulsivity, measured by Barratt Impulsiveness Scale (BIS), was compared between 305 controls (HC), 139 patients with schizophrenia (SZ), 100 with schizoaffective disorder (SZA), and 125 with psychotic bipolar disorder (PBP). In each proband group, impulsivity was associated with regional cortical volumes (using FreeSurfer analysis of T1 MRI scans), suicide attempt history, Global Assessment of Functioning (GAF), and Social Functioning Scale (SFS). BIS scores were found to differ significantly between participant groups, with SZA and PBP exhibiting significantly higher impulsivity than SZ, which exhibited significantly higher impulsivity than HC. BIS scores were significantly related to suicide attempt history, and they were inversely associated with GAF, SFS, and bilateral orbitofrontal cortex (OFC) volume in both SZA and PBP, but not SZ. These findings indicate that psychotic disorders, particularly those with prominent affective symptoms, are characterized by elevated self-reported impulsivity measures. Impulsivity's correlations with suicide attempt history, GAF, and SFS suggest that impulsivity may be a mediator of clinical outcome. The observed impulsivity-OFC correlations corroborate the importance of OFC deficits in impulsivity. These correlations' presence in SZA and PBP but not in SZ suggests that impulsivity may have different underlying mechanisms in affective and non-affective psychotic disorders.

Comorbid obsessive-compulsive disorder with bipolar disorder: A distinct form?

We examined whether the patients with Bipolar Disorder (BD) and Obsessive-Compulsive Disorder (OCD) comorbidity may represent a distinct form of BD. The subjects diagnosed with BD (n=48), OCD (n=61), and BD with OCD (n=32) were compared in terms of several socio-demographic and clinical characteristics. Previous history of suicidal attempts was more likely to be higher in BD-OCD group compared to the other two groups. A more episodic course of OCD, higher rates of rapid cycling, and the seasonality were found in BD-OCD patients. The frequency of bipolar II and NOS subtypes was more prevalent in patients with BD-OCD than in OCD patients. The first diagnosed illness was BD in the majority of BD-OCD cases. It was found that first affective episode was major depression in half of BD-OCD patients. Age at onset of BD was found to be earlier in BD-OCD group compared to pure BD patients. Bipolarity may not have a specific effect on the phenomenology of OC symptoms. The episodic course of OCD, seasonality, rapid cycling, earlier onset of BD, and impulsivity in BD-OCD patients may be indicative for a distinct form of BD.

Mood disorders: neurocognitive models

OBJECTIVES

In recent years, a number of neurocognitive models stemming from psychiatry and psychology schools of thought have conceptualized the pathophysiology of mood disorders in terms of dysfunctional neural mechanisms that underpin and drive neurocognitive processes. Though these models have been useful for advancing our theoretical understanding and facilitating important lines of research, translation of these models and their application within the clinical arena have been limited-partly because of lack of integration and synthesis. Cognitive neuroscience provides a novel perspective for understanding and modeling mood disorders. This selective review of influential neurocognitive models develops an integrative approach that can serve as a template for future research and the development of a clinically meaningful framework for investigating, diagnosing, and treating mood disorders.

METHODS

A selective literature search was conducted using PubMed and PsychINFO to identify prominent neurobiological and neurocognitive models of mood disorders.

RESULTS

Most models identify similar neural networks and brain regions and neuropsychological processes in the neurocognition of mood, however, they differ in terms of specific functions attached to neural processes and how these interact. Furthermore, cognitive biases, reward processing and motivation, rumination, and mood stability, which play significant roles in the manner in which attention, appraisal, and response processes are deployed in mood disorders, are not sufficiently integrated. The inclusion of interactions between these additional components enhances our understanding of the etiology and pathophysiology of mood disorders.

CONCLUSIONS

Through integration of key cognitive functions and understanding of how these interface with neural functioning within neurocognitive models of mood disorders, a framework for research can be created for translation to diagnosis and treatment of mood disorders.

Response inhibition and interference control in patients with bipolar I disorder and first-degree relatives

OBJECTIVES

The current study aimed to assess both response inhibition (RI) and interference control (IC) in euthymic patients with bipolar disorder (BD-Ps) as well as asymptomatic first-degree relatives (BD-Rs) and healthy controls (HCs) in order to evaluate trait-as opposed to illness-associated features of these components.

METHODS

BD-Ps (n = 35) who had been in the euthymic state for at least six months, BD-Rs (n = 30), and HCs (n = 33) completed a Stop-Signal Task (SST) and Stroop Task to assess RI and IC, respectively. Groups were compared on the stop-signal reaction time (SSRT), stop-signal delay (SSD), mean reaction time on go trials (go-RT), Stroop interference score (S-interference), and number of errors on the color-word-naming trial (S-error). Associations between the patient's clinical features and RI and IC, between the patient's treatment and RI and IC, and between RI and IC in each group were investigated.

RESULTS

BD-Ps and BD-Rs had significantly shorter go-RT and SSD, and longer SSRT compared to HCs, with these scores being similar between the BD-Ps and BD-Rs. Also, both BD-Ps and BD-Rs made significantly more S-errors than HCs, whereas, the S-interference score was not significantly different between groups. There were no significant correlations between Stroop Task and SST scores within each group, nor between clinical features or treatment variables and RI and IC in BD-Ps.

CONCLUSIONS

Overall, impairment in RI and IC (only on S-error score) was present in both patients and relatives. The persistence of these deficits in the absence of mood symptoms suggests that these features may represent candidate endophenotypes for bipolar disorder.

Vulnerability for mania - is it linked to problems delaying gratification?

Impulsivity is described as one of the main risk factors for mania. One facet of impulsivity, the inability to delay gratification, might be of special relevance, because a hypersensitivity to reward is hypothesized to be related to mania. The main aim of this study was to examine whether risk for mania is associated with deficits in the ability to delay gratification using both a behavioral and a self-report (UPPS) measure. An additional reason for choosing the UPPS was to see if prior results about an association between risk for mania and positive urgency could be replicated. Thirty-three individuals at risk for mania and a matched control group were selected using the Hypomanic Personality Scale and interviewed for a history of mood disorders. The main outcome measures were the Single-Key-Impulsivity-Paradigm and Monetary Choice Questionnaire. The groups did not differ in measures of gratification delay but we replicated other studies reporting significantly higher levels of positive urgency and sensation seeking in at-risk individuals. We suggest that individuals at risk might not generally be more impulsive but rather that impulsive behaviors might be triggered in response to specific mood states.

Verbal learning impairment in euthymic bipolar disorder: BDI v BDII

OBJECTIVES

Cognitive impairment is known to occur in bipolar disorder (BD), even in euthymic patients, with largest effect sizes often seen in Verbal Learning and Memory Tasks (VLT). However, comparisons between BD Type-I and Type-II have produced inconsistent results partly due to low sample sizes.

METHODS

This study compared the performance of 183 BDI with 96 BDII out-patients on an adapted version of the Rey Verbal Learning Task. Gender, age, years of education, mood scores and age at onset were all used as covariates. Current medication and a variety of illness variables were also investigated for potential effects on VLT performance.

RESULTS

BDI patients were significantly impaired relative to BDII patients on all five VLT outcome measures after controlling for the other variables [Effect Sizes=.13-.17]. The impairments seem to be unrelated to drug treatment and largely unrelated to illness variables, although age of onset affected performance on three outcome measures and number of episodes of mood elevation affected performance on one.

LIMITATIONS

This study used historical healthy controls. Analysis of potential drug effects was limited by insufficient participants not being drug free. Cross-sectional nature of the study limited the analysis of the potential effect of illness variables.

CONCLUSIONS

This study replicates earlier findings of increased verbal learning impairment in BDI patients relative to BDII in a substantially larger sample. Such performance cannot be wholly explained by medication effects or illness variables. Thus, the cognitive impairment is likely to reflect a phenotypic difference between bipolar sub-types.

Increased impulsivity as a vulnerability marker for bipolar disorder: evidence from self-report and experimental measures in two high-risk populations

BACKGROUND

Heightened impulsivity has been suggested as a possible risk factor for bipolar disorder (BD). However, studies on high-risk populations are scarce and have mainly focused on individuals with a genetic risk. The present study investigated two high-risk samples for BD with regard to several aspects of the impulsivity construct.

METHODS

Unaffected relatives of BD patients (genetically defined high-risk group, N=29) and participants scoring high on the Hypomanic Personality Scale (psychometrically defined high-risk sample, N=25) were being compared to respective control groups (N=27 and N=25) using a multi-method approach. Participants were accessed on the Barratt Impulsiveness Scale-11 (BIS-11, trait impulsivity), the Stop Signal Task (response inhibition), and the Cambridge Gambling Task (impulsive behavior in decision-making processes).

RESULTS

Both high-risk groups reported heightened impulsivity on the BIS-11, as well as impulsive decision-making, whereas no significant group differences in response inhibition were observed.

LIMITATIONS

Limitations were the lack in specificity of the results for BD and the cross-sectional study design, which does not allow conclusions about the influence of impulsivity on the development of or resilience for BD in risk groups.

CONCLUSIONS

Our findings support the assumption that increased trait impulsivity and impulsive decision-making are a vulnerability marker for and an endophenotype of BD.

Eating behavior and obesity in bipolar disorder

OBJECTIVES

Individuals with bipolar disorder are more frequently overweight or obese than the general population, but the reasons for this association are unknown. The aim of this study is to further understand the etiology of overweight and obesity in bipolar disorder.

METHODS

We invited patients in a specialty outpatient bipolar clinic to complete the Eating Inventory. Patients provided self-reported restraint, disinhibition, and perceived hunger as well as general perceptions of dietary intake.

RESULTS

Sixty-two individuals (37 female) between the ages of 18 and 67 (M = 41.5, SD = 13.38) and with an average body mass index (BMI) of 27.18 (SD = 5.71) completed the survey. Disinhibition and perceived hunger were positively correlated with BMI and self-reported difficulty eating healthy foods. Restraint was positively correlated with healthy eating (ps < .05). Stepwise linear regressions revealed that hunger was the most significant predictor of BMI (F(1) = 8.134, p = .006). Those participants with bipolar I or II disorder reported greater hunger scores (p < .01) and difficulty eating healthily (p < .05) than those without a full diagnosis.

CONCLUSIONS

These results suggest that disinhibition and perception of hunger may be linked to the disproportionately high rate of obesity in bipolar disorder.

Normal Metabolic Levels in Prefrontal Cortex in Euthymic Bipolar I Patients with and without Suicide Attempts

Introduction/Objective. Evidence suggests that the prefrontal cortex has been implicated in the pathophysiology of bipolar disorder (BD), but few neurochemical studies have evaluated this region in bipolar patients and there is no information from BD suicide attempters using Proton Magnetic Resonance Spectroscopy (H⁺MRS). The objective was to evaluate the metabolic function of the medial orbital frontal cortex in euthymic BD type I suicide and nonsuicide attempters compared to healthy subjects by H⁺MRS. Methods. 40 euthymic bipolar I outpatients, 19 without and 21 with history of suicide attempt, and 22 healthy subjects were interviewed using the Structured Clinical Interview with the DSM-IV axis I, the Hamilton Depression Rating Scale, the Young Mania Rating Scale, and the Barratt Impulsiveness Scale-11 and underwent H⁺MRS. Results. We did not find any metabolic abnormality in medial orbital frontal regions of suicide and nonsuicide BD patients and BD patients as a group compared to healthy subjects. Conclusions. The combined chronic use of psychotropic drugs with neuroprotective or neurotrophic effects leading to a euthymic state for longer periods of time may improve neurometabolic function, at least measured by H⁺MRS, even in suicide attempters. Besides, these results may implicate mood dependent alterations in brain metabolic activity. However, more studies with larger sample sizes of this heterogeneous disorder are warranted to clarify these data.

Left temporal activation associated with depression severity during a verbal fluency task in patients with bipolar disorder: a multichannel near-infrared spectroscopy study

BACKGROUND

Neuroimaging studies using multichannel near-infrared spectroscopy (NIRS) have provided compelling evidence about the dysfunction of the frontotemporal cortices in patients with bipolar disorder (BD). However, it remains unclear whether the dysfunction is associated with mood state or symptom severity. Using NIRS, we aimed to clarify differences in oxygenated hemoglobin (oxy-Hb) activation between depressive and euthymic states as well as regional brain dysfunction in relation to symptom severity in BD.

METHODS

Fifty-five patients with BD, including 30 with bipolar depression (BPD) and 25 with euthymic bipolar disorder (BPE), and 28 healthy controls (HCs) participated in the study. Regional hemodynamic changes during a verbal fluency task (VFT) were monitored using a 52-channel NIRS apparatus.

RESULTS

The mean oxy-Hb changes induced by VFT were significantly smaller in the BD patients than in the HCs in 18 channels in the frontotemporal regions (false-discovery rate p<0.05, p=0.000-0.011). The BPD group exhibited significantly smaller changes in mean oxy-Hb compared with the BPE group in three channels of the left temporal region (p=0.005-0.014). In the BD patients, significant negative correlations were observed between mean oxy-Hb changes in the left temporal regions and the severity of depression.

LIMITATIONS

Our sample size was small, making the results susceptible to type II errors.

CONCLUSIONS

BD patients have persistent hypofunction of the frontotemporal cortical regions. Moreover, the hemodynamic response in the left temporal regions is associated with symptom severity.

Emotion regulation in bipolar disorder: profile and utility in predicting trait mania and depression propensity

Current emotion regulation research in BD has tended to focus on the extent to which patients control their emotions using different cognitive strategies. Fewer studies have investigated whether patients with BD have difficulties in regulating other dimensions of emotion that serve a functional purpose and are thereby more amenable to change. To overcome this paucity of research we utilised a multi-dimensional measure of emotion regulation to characterise the emotion regulation profile of BD, and examine its utility in predicting trait mania and depression propensity. Fifty BD patients and 52 healthy controls completed the Difficulties in Emotion Regulation Scale (DERS) and the General Behaviour Inventory (GBI). Results indicated that patients had difficulties in emotion regulation across a range of dimensions. Impulse control difficulties most parsimoniously predicted trait (hypo)mania propensity in BD patients, whilst poor access to mood regulation strategies predicted depressive propensity. Predictors of the propensity to experience these moods differed in the control group. These findings represent an important step toward informing the development of new treatment strategies to remediate emotion regulation difficulties and improve BD symptomatology.

Cognitive control of gaze in bipolar disorder and schizophrenia

The objective of the present study was to compare two components of executive functioning, response monitoring and inhibition, in bipolar disorder (BP) and schizophrenia (SZ). The saccadic countermanding task is a translational paradigm optimized for detecting subtle abnormalities in response monitoring and response inhibition. We have previously reported countermanding performance abnormalities in SZ, but the degree to which these impairments are shared by other psychotic disorders is unknown. 18 BP, 17 SZ, and 16 demographically matched healthy controls (HC) participated in a saccadic countermanding task. Performance on the countermanding task is approximated as a race between movement generation and inhibition processes; this model provides an estimate of the time needed to cancel a planned movement. Response monitoring was assessed by the reaction time (RT) adjustments based on trial history. Like SZ patients, BP patients needed more time to cancel a planned movement. The two patient groups had equivalent inhibition efficiency. On trial history-based RT adjustments, however, we found a trend towards exaggerated trial history-based slowing in SZ compared to BP. Findings have implications for understanding the neurobiology of cognitive control, for defining the etiological overlap between schizophrenia and bipolar disorder, and for developing pharmacological treatments of cognitive impairments.

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

Recent advances in genome-wide association studies are pointing towards a major role for voltage-gated ion channels in neuropsychiatric disorders and, in particular, bipolar disorder (BD). The phenotype of BD is complex, with symptoms during mood episodes and deficits persisting between episodes. We have tried to elucidate the common neurobiological mechanisms associated with ion channel signaling in order to provide a new perspective on the clinical symptoms and possible endophenotypes seen in BD patients. We propose a model in which the multiple variants in genes coding for ion channel proteins would perturb motivational circuits, synaptic plasticity, myelination, hypothalamic-pituitary-adrenal axis function, circadian neuronal rhythms, and energy regulation. These changes in neurobiological mechanisms would manifest in endophenotypes of aberrant reward processing, white matter hyperintensities, deficits in executive function, altered frontolimbic connectivity, increased amygdala activity, increased melatonin suppression, decreased REM latency, and aberrant myo-inositol/ATP shuttling. The endophenotypes result in behaviors of poor impulse control, motivational changes, cognitive deficits, abnormal stress response, sleep disturbances, and energy changes involving different neurobiological process domains. The hypothesis is that these disturbances start with altered neural circuitry during development, following which multiple environmental triggers may disrupt the neuronal excitability balance through an activity-dependent molecular process, resulting in clinical mood episodes.

Working Memory and Response Inhibition in Patients With Bipolar I Disorder During Euthymic Period

Background:

Several cognitive domains, including attention, memory, and executive functions are impaired in bipolar disorder.

Objectives:

This study aimed to investigate two executive functions (working memory and response inhibition) in patients with bipolar I disorder during remission of the symptoms.

Patients and Methods:

In this case-control design, 30 bipolar I patients (18 to 45 years old) were matched with 30 ones in the control group in terms of age, gender, and education. The patients were selected from Roozbeh Psychiatric Hospital (a hospital affiliated to Tehran University of Medical Sciences) from May to October 2013. They were evaluated and contrasted using working memory (Spatial Span and Spatial Working Memory (SSP and SWM)) and response inhibition (Stop Signal Task (SST)) tests.

Results:

We used independent t-tests for comparing and contrasting 2 groups on total and sub-scales scores of these 3 tests. In terms of SWM test there was a significant difference in between-group error between the two groups (P = 0.05); there was also a meaningful difference between the strategies used by two groups (P = 0.05). In SSP test, a significant difference appeared between averages of span length of the two groups. In the first and last item delays, there was also a clear difference, but the total error index was not noticeably different. In SST test, the direction error indicator in start-stop trials indicated a major difference, while in successful stops ratio, the case group had a lower ratio. In addition, reaction time to stop signs in bipolar group was meaningfully lower than the control group.

Conclusion:

In conclusion, even during remission phase, executive dysfunction is detectable at least in some areas in patients with bipolar disorder.

Resilience and impulsivity in euthymic patients with bipolar disorder

BACKGROUND

Stress plays an important role in the onset and recurrence of bipolar disorder (BD). Resilience is the ability to cope with stress or adversity. Few studies have examined resilience in BD, and this study aimed to investigate the clinical correlates of resilience in euthymic patients with BD.

METHODS

A total of 62 outpatients with BD type I, II, and not otherwise specified (NOS) who were in remission and 62 healthy individuals matched with the BD group in terms of age and sex were recruited. All participants completed the Connor-Davidson Resilience Scale and Barratt Impulsiveness Scale. A psychiatrist interviewed the subjects to assess clinical characteristics. Multiple linear regression analysis was used to determine factors associated with resilience.

RESULTS

The BD group had significantly higher levels of impulsivity and lower levels of resilience compared with the control group. Degree of impulsivity, number of depressive episodes, Clinical Global Impression (CGI) scores, and length of education were significantly correlated with resilience. Attention impulsivity, non-planning impulsivity, and number of depressive episodes were associated with low levels of resilience, even when age, sex, length of education, and CGI scores were controlled.

LIMITATIONS

Because tertiary hospital patients were recruited, the generalizability of the findings is limited.

CONCLUSIONS

This study shows that low levels of resilience are related to high levels of impulsivity and to an increased number of depressive episodes in euthymic patients with BD. Given the reciprocal relationship between resilience and impulsivity, efforts to enhance resilience and reduce impulsivity may make important contributions to the treatment of patients with BD.

Trait impulsivity and increased pre-attentional sensitivity to intense stimuli in bipolar disorder and controls

Impulsivity and sensation seeking are stimulus-oriented traits. Because they differ in degree of intention and planning, they may have distinct neurophysiological mechanisms. Impulsivity is prominent in bipolar disorder, and may be related to pre-attentional information filtering and stimulus-orientation. We investigated specificity of relationships between impulsivity and sensitivity to stimulus intensity in bipolar disorder and controls, using intensity-sensitivity of auditory evoked potentials. Seventy-six subjects (37 healthy controls, 39 with bipolar disorder) were administered an intensity-sensitivity paradigm. Additional measures included Barratt Impulsiveness Scale (BIS-11) and Eysenck Impulsivity and Venturesomeness scores. State-dependent rapid-response impulsivity was measured using the Immediate Memory Task. Intensity-sensitivities of the auditory evoked P1N1, N1P2, P1, N1, and P2 potentials were assessed as the slope of amplitude relative to loudness. Analyses used general linear models (GLM) with impulsivity-related measures as dependent variables and age, gender, education, and diagnosis as dependent variables. BIS-11 total, motor, and attentional impulsivity scores correlated positively with pre-attentional N1 and P1N1 intensity-sensitivity slopes in bipolar disorder, but not in controls. BIS-11 nonplanning and Eysenck Venturesomeness scores did not correlate with intensity-sensitivity. Intensity-sensitivity slopes did not correlate with rapid-response impulsivity. Correlations between N1 or P1N1 slopes and BIS-11 scores in bipolar disorder were not affected by age, education, WAIS, treatment, symptoms, or gender. Trait impulsivity in bipolar disorder may be related to poorly modulated stimulus-driven late pre-attentional responses to stimuli, potentially resulting in exaggerated responses to intense stimuli even before conscious awareness. Components of trait impulsivity are physiologically heterogenous relative to intensity-sensitivity.

Different impulsivity profiles in borderline personality disorder and bipolar II disorder

INTRODUCTION

Borderline personality disorder (BPD) and bipolar II disorder (BP II) share clinical characteristics including impulsivity. Their relationship is disputed. In this study, we investigated self-reported impulsivity in these patient groups and in a healthy control group. Effects of current mood state and of traumatic childhood experiences were explored.

METHODS

Twenty-five patients with BPD without comorbid bipolar disorder; 20 patients with BP II without comorbid BPD; and 44 healthy control subjects completed the UPPS questionnaire which yields assessments of four components of impulsivity: Urgency, Lack of Premeditation, Lack of Perseverance, and Sensation Seeking. Current mood state was rated using the Montgomery Asberg Depression Rating Scale (MADRS), and the Young Mania Rating Scale (YMRS). Traumatic childhood experiences were assessed using the Childhood Trauma Questionnaire (CTQ). Group differences in UPPS levels; and effects of mood state and CTQ score on UPPS scores in patients were investigated.

RESULTS

BPD patients showed significantly higher levels of Urgency and Lack of Perseverance than BP II patients and controls, and a significantly higher level of Lack of Premeditation than controls. BP II patients showed higher levels of Urgency and Lack of Perseverance than controls. In BP II, higher MADRS scores were associated with higher impulsivity scores. Also, higher CTQ scores were associated with higher Urgency scores in BP II.

LIMITATIONS

Relatively small sample size; cross-sectional assessment of influence of mood state.

CONCLUSIONS

BPD patients exhibited markedly elevated UPPS impulsivity scores compared with healthy controls and BP II patients, and the elevations were not related to current mood state. BP II patients showed moderately elevated impulsivity scores which were associated with a depressed mood state and to some extent with a history of childhood trauma. The findings suggest that BPD and BP II have different impulsivity profiles.

Impulsivity predicts time to reach euthymia in adults with bipolar disorder

OBJECTIVES

Specific demographic and illness characteristics have been identified as predictors of overall morbidity and treatment course among individuals with bipolar disorder. However, the role of specific cognitive limitations on disease severity and treatment response is unclear. The present study evaluated whether impulsiveness during acute mania was a significant predictor of achieving euthymia within one year following psychiatric hospitalization.

METHODS

Participants were 94 adult inpatients (60 manic) with bipolar I disorder. Baseline symptom severity was assessed using the Young Mania Rating Scale and the Montgomery-Åsberg Depression Rating Scale. Impulsivity was measured with the Stop Signal Task, Degraded Stimulus Continuous Performance Task, Delayed Response Task, and Barratt Impulsiveness Scale-11.

RESULTS

Individual predictors of time to reach euthymia included fewer depressive symptoms and better impulse control at baseline, later age at illness onset, shorter illness duration, and the absence of comorbid attention-deficit hyperactivity disorder. Self-reported impulsivity was a significant independent predictor of time to euthymia, even after accounting for relevant clinical variables.

CONCLUSIONS

Better trait impulse control may be associated with better treatment responsiveness among adults with bipolar disorder.

Behavioral response inhibition in psychotic disorders: diagnostic specificity, familiality and relation to generalized cognitive deficit

Difficulty inhibiting context-inappropriate behavior is a common deficit in psychotic disorders. The diagnostic specificity of this impairment, its familiality, and its degree of independence from the generalized cognitive deficit associated with psychotic disorders remain to be clarified. Schizophrenia, schizoaffective and bipolar patients with history of psychosis (n=523), their available first-degree biological relatives (n=656), and healthy participants (n=223) from the multi-site B-SNIP study completed a manual Stop Signal task. A nonlinear mixed model was used to fit logistic curves to success rates on Stop trials as a function of parametrically varied Stop Signal Delay. While schizophrenia patients had greater generalized cognitive deficit than bipolar patients, their deficits were similar on the Stop Signal task. Further, only bipolar patients showed impaired inhibitory control relative to healthy individuals after controlling for generalized cognitive deficit. Deficits accounted for by the generalized deficit were seen in relatives of schizophrenia and schizoaffective patients, but not in relatives of bipolar patients. In clinically stable patients with psychotic bipolar disorder, impaired inhibitory behavioral control was a specific cognitive impairment, distinct from the generalized neuropsychological impairment associated with psychotic disorders. Thus, in bipolar disorder with psychosis, a deficit in inhibitory control may contribute to risk for impulsive behavior. Because the deficit was not familial in bipolar families and showed a lack of independence from the generalized cognitive deficit in schizophrenia spectrum disorders, it appears to be a trait related to illness processes rather than one tracking familial risk factors.

Is impulsivity in remitted bipolar disorder a stable trait? A meta-analytic review

OBJECTIVE

To review scores on measures of impulsivity in remitted bipolar disorder.

DATA SOURCE

We used keywords "impulsivity and bipolar" and "impulsivity and mania" to narrow down our search on Medline, EMBASE and Psychinfo to include those studies that had reported impulsivity scores using validated and reliable assessment measures in remitted bipolar disorder (both I and II). We searched all English language studies from 1990 to October 2012.

STUDY SELECTION

Nineteen reports met the inclusion criteria and were reviewed by two abstractors independently.

DATA ABSTRACTION

We generated weighted mean differences (WMDs) from pooled data using RevManager 5.0 from Cochrane analysis.

RESULTS

The Barratt Impulsivity Scale (BIS) 11 was the instrument most commonly used. Nineteen studies met the inclusion criteria, of which 2 were excluded due to incomplete data. A WMD of 12.8 was observed for BIS 11 total scores, 4.3 on the motor component, 4.1 on the cognitive and 7.6 on the non-planning components of the BIS 11 respectively.

CONCLUSION

Impulsivity is significantly higher in remitted bipolar patients than normal controls. Non-planning impulsivity is a key domain affected in bipolar disorder, which may represent a stable trait.

Heart rate variability in unmedicated patients with bipolar disorder in the manic phase

AIMS

Decreased heart rate variability (HRV) has been proposed in bipolar disorder. To date, there has been no adequate study that has investigated resting HRV in unmedicated patients with bipolar disorder in the manic state.

METHODS

To examine whether bipolar mania is associated with decreased HRV, 61 unmedicated patients with bipolar mania and 183 healthy volunteers aged 20-65 years were recruited for this case-control analysis. The Young Mania Rating Scale (YMRS), Clinical Global Impression-Severity, Hamilton Depression Rating Scale (HAM-D), and Hamilton Anxiety Rating Scale (HAM-A) were used for the clinical ratings. Cardiac autonomic function was evaluated by measuring HRV parameters and the frequency-domain indices of HRV were obtained.

RESULTS

Patients with bipolar mania exhibited significantly lower mean RR interval, variance, low-frequency (LF)-HRV, and high-frequency (HF)-HRV but higher LF/HF compared to controls. Decreased HRV (variance) was associated with the YMRS total scores. Both the YMRS total scores and the Clinical Global Impression-Severity scores were positively correlated with the LH/HF ratio and inversely correlated with the HF-HRV. There was no significant correlation between the HAM-D/HAM-A scores and any HRV parameter.

CONCLUSIONS

Bipolar mania is associated with cardiac autonomic dysregulation, highlighting the importance of assessing HRV in manic patients. Further studies examining the influence of anti-manic psychotropic drugs on cardiac autonomic regulation in bipolar mania are needed.

Modulation of brain response to emotional conflict as a function of current mood in bipolar disorder: preliminary findings from a follow-up state-based fMRI study

We used functional magnetic resonance imaging (fMRI) to examine affective control longitudinally in a group of patients with bipolar disorder (BD). Participants comprised 12 BD patients who underwent repeated fMRI scans in euthymic (n=11), depressed (n=9), or hypomanic (n=9) states, and were compared with 12 age-matched healthy controls. During fMRI, participants performed an emotional face-word interference task with either low or high attentional demands. Relative to healthy controls, patients showed decreased activation of the cognitive control network normally associated with conflict processing, more severely during hypomania than during depression, but regardless of level of task demand in both cases. During euthymia, a decreased response to conflict was observed only during the high load condition. Additionally, unlike healthy participants, patients exhibited deactivation in several key areas in response to emotion-conflict trials - including the rostral anterior cingulate cortex during euthymia, the hippocampus during depression, and the posterior cingulate cortex during hypomania. Our results indicate that the ability of BD patients to recruit control networks when processing affective conflict, and the abnormal suppression of activity in distinct components of the default mode network, may depend on their current clinical state and attentional demand.

Impulsivity in children and adolescents with mood disorders and unaffected offspring of bipolar parents

OBJECTIVE

Increased impulsivity seems to be present across all phases of bipolar disorder (BD). Impulsivity may therefore represent an endophenotype for BD, if it is also found among normal individuals at high genetic risk for mood disorders. In this study, we assessed impulsivity across four different groups of children and adolescents: patients with BD, major depressive disorder (MDD) patients, unaffected offspring of bipolar parents (UO), and healthy controls (HC).

SUBJECTS AND METHODS

52 patients with BD, 31 with MDD, 20 UO, and 45 HC completed the Barratt Impulsiveness Scale (BIS-11), an instrument designed to measure trait impulsivity.

RESULTS

UO displayed significantly higher total BIS-11 impulsivity scores than HC (p=0.02) but lower scores than BD patients (F=27.12, p<0.01). Multiple comparison analysis revealed higher BIS-11 total scores among BD patients when compared to HC (p<0.01) and UO (p<0.01). MDD patients had higher BIS-11 scores when compared to HC (p<0.01). Differences between MDD patients and UO, as well as between MDD and BD patients, were not statistically significant.

CONCLUSION

Our findings suggest that trait impulsivity is increased among children and adolescents with mood disorders, as well as in unaffected individuals at high genetic risk for BD.

Decision-making and trait impulsivity in bipolar disorder are associated with reduced prefrontal regulation of striatal reward valuation

Bipolar disorder is characterized by impaired decision-making captured in impulsivity and risk-taking. We sought to determine whether this is driven by a failure to effectively weight the lower-order goal of obtaining a strongly desired reward in relation to higher-order goals, and how this relates to trait impulsivity and risk-taking. We hypothesized that in bipolar disorder the weighting of valuation signals converging on ventromedial prefrontal cortex are more heavily weighted towards ventral striatum inputs (lower-order), with less weighting of dorsolateral prefrontal cortex inputs (higher-order). Twenty euthymic patients with bipolar disorder not in receipt of antipsychotic medication and 20 case-matched controls performed a roulette task during functional magnetic resonance imaging. Activity in response to high-probability ('safe') and low-probability ('risky') prospects was measured during both anticipation, and outcome. In control subjects, anticipatory and outcome-locked activity in dorsolateral prefrontal cortex was greater for safe than risky reward prospects. The bipolar disorder group showed the opposite pattern with preferential response to risky rewards. This group also showed increased anticipatory and outcome-locked activity in ventral striatum in response to rewards. In control subjects, however, ventromedial prefrontal activation was positively associated with both ventral striatum and dorsolateral prefrontal activity; patients evidenced a strong positive association with ventral striatum, but a negative association with dorsolateral prefrontal cortex. Response to high-probability rewards in dorsolateral prefrontal cortex was inversely associated with trait impulsivity and risk-taking in the bipolar disorder group. Our findings suggest that clinically impulsive and risky decision-making are related to subjective valuation that is biased towards lower-order preference, with diminished integration of higher-order goals. The findings extend a functional neuroanatomical account of disorders characterized by clinically impulsive decision-making, and provide targets for evaluating interventions that foster self-control.

Disturbed anterior prefrontal control of the mesolimbic reward system and increased impulsivity in bipolar disorder

Bipolar disorder (BD) is characterized by recurrent mood episodes ranging from severe depression to acute full-blown mania. Both states of this severe psychiatric disorder have been associated with alterations of reward processing in the brain. Here, we present results of a functional magnetic resonance imaging (fMRI) study on the neural correlates and functional interactions underlying reward gain processing and reward dismissal in favor of a long-term goal in bipolar patients. Sixteen medicated patients diagnosed with bipolar I disorder, euthymic to mildly depressed, and sixteen matched healthy controls performed the 'desire-reason dilemma' (DRD) paradigm demanding rejection of priorly conditioned reward stimuli to successfully pursue a superordinate goal. Both groups exhibited significant activations in reward-related brain regions, particularly in the mesolimbic reward system. However, bipolar patients showed reduced neural responses of the ventral striatum (vStr) when exploiting a reward stimulus, and exhibited a decreased suppression of the reward-related activation of the mesolimbic reward system while having to reject immediate reward in favor of the long-term goal. Further, functional interaction between the anteroventral prefrontal cortex and the vStr in the 'DRD' was significantly impaired in the bipolar group. These findings provide evidence for a reduced responsivity of the vStr to reward stimuli in BD, possibly related to clinical features like anhedonia. The disturbed top-down control of mesolimbic reward signals by prefrontal brain regions in BD can be interpreted in terms of a disease-related enhanced impulsivity, a trait marker of BD.

Association between GSK3β gene and increased impulsivity in bipolar disorder

Bipolar patients present increased levels of impulsivity even during remission periods. It is known that this dimensional trait negatively impacts on the course of illness and worsens their prognosis and outcome. Evidence from both basic and clinical researches supports that Lithium (Li) may decrease impulsivity. Owing to the fact that Li inhibits both glycogen synthetase kinase-3 (GSK3) isoenzimes, our aim was to analyze the potential impact of genetic variants located at the GSK3 α and β genes on impulsivity levels in a bipolar sample. Our sample consisted of 199 unrelated Caucasian bipolar outpatients who were recruited from the Bipolar Disorder Unit of the Hospital Clinic of Barcelona and from primary care settings from Oviedo. Four polymorphisms at the GSK3 α and β genes were genotyped in order to analyze the impact of genetic variability on impulsivity as measured by the BIS-11 scale. Single SNP analysis showed that patients carrying T and G alleles at the rs1732170-GSK3β and the rs334558-GSK3β, respectively, presented increased levels of attentional impulsivity compared to non-carriers. These results were also confirmed by haplotype analysis. Our results suggest that genetic variability at GSK3β gene is associated to increased impulsivity in bipolar patients.

Impulsivity: present during euthymia in bipolar disorder? - a systematic review

Because impulsivity is part of the presentation of bipolar disorder (BD) and is associated with its course, this systematic review presents the evidence whether increased impulsivity is present in a stable, euthymic mood and therefore potentially a vulnerability marker for BD. A multi-faceted model of impulsivity was adopted to explore how different facets may relate differently to BD. The evidence was explored in relation to studies employing measures of trait impulsivity (in self-report format) and studies exploring impulsivity with behavioural paradigms. Behavioural paradigms were separated into studies measuring response inhibition and those measuring the ability to delay gratification. Twenty-three papers met the inclusion criteria. Most studies using self-report measures found significant differences between euthymic BD patients and healthy controls. There was little evidence of increased impulsivity as measured by behavioural paradigms. Most studies found no significant difference in response inhibition between groups, though it is possible that much of the literature in this area was underpowered to detect an effect. Only five studies explored delay of gratification, of which the two methodologically strongest studies found no group differences. In conclusion, there is evidence that euthymic patients with BD report increased impulsivity when using self-ratings. However, there is currently limited evidence of impulsivity on behavioural measures assessing response inhibition, and this might be restricted to more severe cases. More research is needed on the ability to delay gratification before drawing any conclusions. However, to establish facets of impulsivity as vulnerability markers, future studies should include at-risk individuals to evaluate whether self-rated or behavioural impulsivity precedes the onset of BD.

A profile approach to impulsivity in bipolar disorder: the key role of strong emotions

OBJECTIVE

Bipolar disorder has been associated with elevated impulsivity - a complex construct subsuming multiple facets. We aimed to compare specific facets of impulsivity in bipolar disorder, including those related to key psychological correlates of the illness: reward sensitivity and strong emotion.

METHOD

Ninety-one individuals diagnosed with bipolar I disorder (inter-episode period) and 80 controls completed several well-validated impulsivity measures, including those relevant to reward (Fun-seeking subscale of the Behavioral Activation System scale) and emotion (Positive Urgency and Negative Urgency scales).

RESULTS

Bipolar participants reported higher impulsivity scores than did controls on all of the impulsivity measures, except the Fun-seeking subscale of the Behavioral Activation System scale. Positive Urgency - a measure assessing the tendency to act impulsively when experiencing strong positive emotion - yielded the largest group differences: F(1,170) = 78.69, P < 0.001, partial η(2)  = 0.316. Positive Urgency was also associated with poorer psychosocial functioning in the bipolar group: ΔR(2)  = 0.24, b = -0.45, P < 0.001.

CONCLUSION

Individuals with bipolar I disorder appear to be at particular risk of behaving impulsively when experiencing strong positive emotions. Findings provide an important first step toward developing a more refined understanding of impulsivity in bipolar disorder with the potential to inform targeted interventions.

Allostasis as a conceptual framework linking bipolar disorder and addiction

Bipolar disorders (BDs) and addictions constitute reciprocal risk factors and are best considered under a unitary perspective. The concepts of allostasis and allostatic load (AL) may contribute to the understanding of the complex relationships between BD and addictive behaviors. Allostasis entails the safeguarding of reward function stability by recruitment of changes in the reward and stress system neurocircuitry and it may help to elucidate neurobiological underpinnings of vulnerability to addiction in BD patients. Conceptualizing BD as an illness involving the cumulative build-up of allostatic states, we hypothesize a progressive dysregulation of reward circuits clinically expressed as negative affective states (i.e., anhedonia). Such negative affective states may render BD patients more vulnerable to drug addiction, fostering a very rapid transition from occasional drug use to addiction, through mechanisms of negative reinforcement. The resulting addictive behavior-related ALs, in turn, may contribute to illness progression. This framework could have a heuristic value to enhance research on pathophysiology and treatment of BD and addiction comorbidity.

In your eyes: does theory of mind predict impaired life functioning in bipolar disorder?

BACKGROUND

Deficits in emotion perception and social functioning are strongly implicated in bipolar disorder (BD). Examining theory of mind (ToM) may provide one potential mechanism to explain observed socio-emotional impairments in this disorder. The present study prospectively investigated the relationship between theory of mind performance and life functioning in individuals diagnosed with BD compared to unipolar depression and healthy control groups.

METHODS

Theory of mind (ToM) performance was examined in 26 individuals with remitted bipolar I disorder (BD), 29 individuals with remitted unipolar depression (UD), and 28 healthy controls (CTL) using a well-validated advanced theory of mind task. Accuracy and response latency scores were calculated from the task. Life functioning was measured during a 12 month follow-up session.

RESULTS

No group differences for ToM accuracy emerged. However, the BD group exhibited significantly shorter response times than the UD and CTL groups. Importantly, quicker response times in the BD group predicted greater life functioning impairment at a 12-month follow-up, even after controlling for baseline symptoms.

LIMITATIONS

The stimuli were static representations of emotional states and do not allow for evaluating the appropriateness of context during emotional communication; due to sample size, neither specific comorbidities nor medication effects were analyzed for the BD and UD groups; preliminary status of theory of mind as a construct.

CONCLUSIONS

Results suggest that quickened socio-emotional decision making may represent a risk factor for future functional impairment in BD.