Cognitive Functioning In Bipolar Disorder Research Articles

A five-year follow-up study of neurocognitive functioning in bipolar disorder.

Cognitive dysfunction in bipolar disorder has been well-established in cross-sectional studies; however, there are few data regarding the longitudinal course of cognitive performance in bipolar disorder. The aim of this study was to examine the course of cognitive function in a sample of euthymic patients with bipolar disorder during a five-year follow-up period. Eighty euthymic outpatients with a DSM-IV diagnosis of bipolar disorder and 40 healthy control comparison subjects were neuropsychologically assessed at baseline (T1) and then at follow-up of five years (T2). A neurocognitive battery including the main cognitive domains of speed of processing, working memory, attention, verbal memory, visual memory, and executive function was used to evaluate cognitive performance. Repeated-measures multivariate analyses showed that progression of cognitive dysfunction in patients was not different to that of control subjects in any of the six cognitive domains examined. Only a measure from the verbal memory domain, delayed free recall, worsened more in patients with bipolar disorder. Additionally, it was found that clinical course during the follow-up period did not influence the course of cognitive dysfunction. Cognitive dysfunction that is characteristic of bipolar disorder is persistent and stable over time. Only dysfunction in verbal recall was found to show a progressive course that cannot be explained by clinical or treatment variables.

Association of obesity and treated hypertension and diabetes with cognitive ability in bipolar disorder and schizophrenia.

People with bipolar disorder or schizophrenia are at greater risk for obesity and other cardio-metabolic risk factors, and several prior studies have linked these risk factors to poorer cognitive ability. In a large ethnically homogenous outpatient sample, we examined associations among variables related to obesity, treated hypertension and/or diabetes and cognitive abilities in these two patient populations. In a study cohort of outpatients with either bipolar disorder (n = 341) or schizophrenia (n = 417), we investigated the association of self-reported body mass index and current use of medications for hypertension or diabetes with performance on a comprehensive neurocognitive battery. We examined sociodemographic and clinical factors as potential covariates. Patients with bipolar disorder were less likely to be overweight or obese than patients with schizophrenia, and also less likely to be prescribed medication for hypertension or diabetes. However, obesity and treated hypertension were associated with worse global cognitive ability in bipolar disorder (as well as with poorer performance on individual tests of processing speed, reasoning/problem-solving, and sustained attention), with no such relationships observed in schizophrenia. Obesity was not associated with symptom severity in either group. Although less prevalent in bipolar disorder compared to schizophrenia, obesity was associated with substantially worse cognitive performance in bipolar disorder. This association was independent of symptom severity and not present in schizophrenia. Better understanding of the mechanisms and management of obesity may aid in efforts to preserve cognitive health in bipolar disorder.

Sex Dependence of Cognitive Functions in Bipolar Disorder

The objective of the present study was to assess the performance of lithium treated euthymic bipolar patients in tests measuring spatial working memory (SWM), planning, and verbal fluency and to delineate the influence of gender on cognitive functioning. Fifty-nine euthymic bipolar patients, treated with lithium carbonate for at least 5 yr, were studied. Patients and controls underwent a neuropsychological assessment. Bipolar patients had significantly worse results than the healthy controls in the spatial memory and planning as well as verbal fluency tests. We detected a gender-related imbalance in the SWM results. Deficits in SWM were observed in male-only comparisons but not in female-only comparisons. The SWM scores were significantly poorer in male patients than in male controls. In female-only comparisons, female patients did not have significantly poorer SWM results in any category than their controls. Bipolar women scored worse in some other tests. The present study points to the different patterns of neuropsychological disturbances in female and male patients and suggests that sex-dependent differences should be taken into account in order to tailor the therapeutic intervention aimed at the improvement of cognitive functions.

12‐month longitudinal cognitive functioning in patients recently diagnosed with bipolar disorder

Although cognitive deficits are observed in the early stages of bipolar disorder, the longitudinal course of neuropsychological functioning during this period is unknown. Such knowledge could provide etiologic clues into the cognitive deficits associated with the illness, and could inform early treatment interventions. The purpose of the present study was to evaluate cognitive change in bipolar disorder in the first year after the initial manic episode. From an initial pool of 65 newly diagnosed patients with bipolar disorder (within three months of the end of the first manic or mixed episode) and 36 demographically similar healthy participants, 42 patients [mean age 22.9 years, standard deviation (SD) = 4.0] and 23 healthy participants [mean age 22.9 years (SD = 4.9)] completed baseline, six-month, and one-year neuropsychological assessments of multiple domains including processing speed, attention, verbal and nonverbal memory, working memory, and executive function. Patients also received clinical assessments, including mood ratings. Although patients showed consistently poorer cognitive performance than healthy individuals in most cognitive domains, patients showed a linear improvement over time in processing speed (p = 0.008) and executive function (p = 0.004) relative to the comparison group. Among patients, those without a history of alcohol/substance abuse or who were taken off an antipsychotic treatment during the study showed better improvement. The early course of cognitive functioning in bipolar disorder is likely influenced by multiple factors. Nevertheless, patients with bipolar disorder showed select cognitive improvements in the first year after resolution of their initial manic episode. Several clinical variables were associated with better recovery, including absence of substance abuse and discontinuation of antipsychotic treatment during the study. These and other factors require further investigation to better understand their contributions to longitudinal cognitive functioning in early bipolar disorder.

Antipsychotic medications and cognitive functioning in bipolar disorder: moderating effects of COMT Val108/158Met genotype

BackgroundThere is a negative association between the use of antipsychotics and cognitive functioning in bipolar patients, which may be mediated by altered dopamine signaling in selected brain areas, and moderation thereof by genetic sequence variation such as COMT Val108/158Met. The interaction between antipsychotic drug use and the COMT Val108/158Met genotype on two-year cognitive functioning in bipolar patients was examined.MethodsInteraction between the COMT Val108/158Met and antipsychotics on a composite cognitive measure was examined in 51 bipolar patients who were assessed 12 times at two-monthly intervals over a period of two years (379 observations).ResultsThere was a significant negative effect of the interaction between antipsychotic medications and Val allele load on the composite cognitive measure in bipolar patients (p < 0.001).ConclusionsThe negative effects of antipsychotics on cognitive functioning in bipolar disorder may be moderated by the COMT Val 108/158 Met genotype, with a negative effect of Val allele load. If replicated, the results may be indicative of pharmacogenetic interactions in bipolar disorder.

Evidence for the impact of the CACNA1C risk allele rs1006737 on 2-year cognitive functioning in bipolar disorder

Department of Psychiatry and Psychology, School for Mental Health and Neuroscience, European Graduate School of Neuroscience (EURON), South Limburg Mental Health Research and Teaching Network (SEARCH), Maastricht University Medical Centre Maastricht, GGzE, Institute for Mental Health Care Eindhoven en de Kempen, Eindhoven, The Netherlands and King’s College London, King’s Health Partners, Department of Psychosis Studies, Institute of Psychiatry, London, UK Correspondence to Baer Arts, MD, Department Psychiatry and Psychology, School for Mental Health and Neuroscience, European Graduate School of Neuroscience (EURON), South Limburg Mental Health Research and Teaching Network (SEARCH), Maastricht University, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands Tel: + 31 43 3874130; fax: + 31 43 3875444; e-mail: b.arts@maastrichtuniversity.nl

Autonomic nervous system arousal and cognitive functioning in bipolar disorder

Previous theories about the etiology of cognitive dysfunction in bipolar disorder (BD) emphasized trait factors such as neurological impairment. State factors, other than mood symptoms, that may exacerbate functional deficits have not yet been considered. The purpose of this study was to examine autonomic nervous system (ANS) arousal following cognitive challenge. The study compared patients with BD and healthy controls (HC) in physiological measures and neuropsychological test scores. Thirty euthymic patients with BD and 22 HC completed the study. Participants completed mood [Beck Depression Inventory-II (BDI-II) and Young Mania Rating Scale (YMRS)], anxiety (State-Trait Anxiety Inventory), and substance abuse (Drug Abuse Screening Test-20 item and Alcohol Use Disorders Identification Test) measures. They were connected to an electrogram, a sensitive thermometer for measuring finger temperature, and electrodes that measure galvanic skin response. After a five-min baseline measurement in a restful state, participants completed a computerized neuropsychological battery (CNS Vital Signs). The group with BD reported significantly more mood symptoms (BDI-II, t = 3.71, p < 0.001; YMRS, t = 6.73, p < 0.001) and scored higher on a measure of trait-anxiety (State-Trait Anxiety Inventory, t = 2.91, p < 0.001) than HC. A multivariate analysis of variance revealed higher arousal on all physiological measures in the BD group relative to HC at baseline [F(3,48) = 13.1, p < 0.001] and during cognitive testing [F(3,48) = 11.3, p < 0.001]. The increase in physiological arousal from a restful state to the time of testing was higher for the BD group [F(3,37) = 8.06, p < 0.001]. With respect to cognitive data, HC scored higher than patients with BD across the measures of memory (F = 8.5, p < 0.001), sustained (F = 9.5, p < 0.001) and complex (F = 2.7, p < 0.04) attention, processing speed (F = 10.0, p < 0.001), reaction time (F = 7.8, p < 0.001), cognitive flexibility (F = 19.7, p < 0.001), working memory (F = 10.8, p < 0.001), and social acuity (F = 5.7, p < 0.01), with partial eta-squared from 0.18 to 0.62. Correlational analysis revealed significant associations between various cognitive test scores and changes in physiological arousal from baseline to testing (-0.59 ≤ r ≤ 0.22). Relative to HC, patients with BD experience larger changes in ANS arousal between a restful baseline and cognitive testing, and achieve lower cognitive test scores. Further research is needed to determine whether acute physiological symptoms of anxiety directly compromise cognitive functioning in BD.

Effects of N‐acetyl cysteine on cognitive function in bipolar disorder

Bipolar disorder is characterized by progressive changes in cognition with declines in executive functioning, memory and sustained attention. Current pharmacotherapies for bipolar disorder target mood symptoms but have not addressed these cognitive changes resulting in euthymic individuals who still experience cognitive deficits. N-acetyl cysteine (NAC) has been shown to have effects on antioxidant status, glutamate transmission, inflammation and neurogenesis. Adjunctive treatment with NAC improves the symptoms experienced by those with bipolar disorder, particularly depression, and it was hypothesized that cognition may also be improved following NAC treatment. As part of a larger randomized, double-blind, placebo-controlled trial, participants in the current report were tested at baseline and 6 months to assess changes in cognitive function following either 2000 mg of NAC daily or placebo. This study failed to find changes in cognitive function following treatment with NAC compared to placebo. While an important pilot study, this study had a small sample size and included a limited battery of cognitive tests. Further investigations on the effects of NAC on cognitive performance in bipolar disorder are required.

O-31 - ANS arousal and cognitive functioning in bipolar disorder

Previous theories about the etiology of cognitive dysfunction in bipolar disorder (BD) emphasize trait factors such as chronic neurological impairment. State factors that may contribute to cognitive deficits in BD have not yet been considered. The purpose of this study was to examine changes in autonomic nervous system (ANS) arousal in response to cognitive challenge. The study aimed to determine whether ANS arousal during cognitive testing was associated with test performance in patients with BD and healthy controls (HC). Twenty-eight euthymic patients with BD and twelve HC completed the study. Participants completed mood (BDI-II, YMRS), anxiety (STAI), and substance abuse (DAST, AUDIT) measures. They were then connected to an ECG device, a sensitive thermometer (i.e. measuring figure temperature) and electrodes that measure Galvanic skin Response (GSR). After a 5-minute baseline measurement at rest, participants completed a computerized neuropsychological battery (CNS-VS). The group with BD reported significantly more mood symptoms and scored higher on a measure of state anxiety than HC. At baseline and during testing, analysis revealed higher ANS arousal on all physiological measures in the BD group relative to HC. In addition, the relative increase in arousal from baseline to testing was higher in the BD group. HC scored higher than patients with BD on most memory, attention and executive measures, with effect sizes ranging from 0.8 to 1.3. Acute ANS arousal in response to cognitive challenge, as measured by neuropsychological testing, may increase cognitive deficits in people with BD.

Affective symptoms and intra-individual variability in the short-term course of cognitive functioning in bipolar disorder

Few studies have examined the short-term course of cognitive impairments in bipolar disorder (BD). Key questions are whether trajectories in symptoms covary with cognitive function and whether BD is associated with increased intra-individual variability in cognitive abilities. Forty-two out-patients with BD and 49 normal comparison (NC) subjects were administered a battery of neuropsychological tests at baseline, 6, 12 and 26 weeks, along with concurrent ratings of depressive and manic symptom severity. Mixed-effects regressions were used to model relationships between time, diagnosis and symptom severity on composite cognitive performance. Within-person variance in cognitive functioning across time was calculated for each subject. BD patients had significantly worse performance in cognitive ability across time points, but both groups showed significant improvement in cognitive performance over repeated assessments (consistent with expected practice effects). BD was associated with significantly greater intra-individual variability in cognitive ability than NCs; within-person variation was negatively related to baseline cognitive ability in BD but not NC subjects. Changes in affective symptoms over time did not predict changes in cognitive ability. Moderate changes in affective symptoms did not covary with cognitive ability in BD. The finding of elevated intra-individual variability in BD may reduce capacity to estimate trajectories of cognitive ability in observational and treatment studies.

Mindfulness-Based Cognitive Therapy for Bipolar Disorder

Bipolar disorder is associated with impairments in cognition, including difficulties in executive functioning, even when patients are euthymic (neither depressed nor manic). The purpose of this study was to assess changes in self-reported cognitive functioning in patients with bipolar disorder who participated in an open pilot trial of mindfulness-based cognitive therapy (MBCT). Following MBCT, patients reported significant improvements in executive functioning, memory, and ability to initiate and complete tasks, as measured by the Behavior Rating Inventory of Executive Function (BRIEF) and the Frontal Systems Behavior Scale (FrSBe). Changes in cognitive functioning were correlated with increases in mindful, nonjudgmental observance and awareness of thoughts, feelings, and sensations, and were not associated with decreases in depression. Improvements tended to diminish after termination of treatment, but some improvements, particularly those in executive functioning, persisted after 3 months. These results provide preliminary evidence that MBCT may be a treatment option that can be used as an adjunct to medication to improve cognitive functioning in bipolar disorder.

P.2.e.008 The impact of brief depressive episodes on the outcome of bipolar and major depressive disorder: a 1-year prospective study

Cognitive reserve (CR) reflects the capacity of the brain to endure neuropathology, minimize clinical manifestations and successfully complete cognitive tasks. The present study aims to determine whether high CR may constitute a moderator of cognitive functioning in bipolar disorder (BD).102 patients with BD and 32 healthy controls were enrolled. All patients met DSM-IV criteria for I or II BD and were euthymic (YMRS≤6 and HDRS≤8) during a 6-month period. All participants were tested with a comprehensive neuropsychological battery, and a Cerebral Reserve Score (CRS) was estimated. Subjects with a CRS below the group median were classified as having low CR, whereas participants with a CRS above the median value were considered to have high CR.Participants with BD with high CR displayed a better performance in measures of attention (digits forward: F=4.554, p=0.039); phonemic and semantic verbal fluency (FAS: F=9.328, p=0.004; and Animal Naming: F=8.532, p=0.006); and verbal memory (short cued recall of California Verbal Learning Test: F=4.236, p=0.046), after multivariable adjustment for potential confounders, including number of admissions and prior psychotic symptoms.The cross-sectional design of the study does not allow the establishment of causal inferences. Additionally, the small size of the sample may have limited some results.High cognitive reserve may therefore be a valuable construct to explore for predicting neurocognitive performance in patients with BD regarding premorbid status.

P01-425 - Smoking and neurocognition in schizophrenia and bipolar disorder

IntroductionSeveral studies have suggested that nicotine could have beneficial effects on cognitive functioning.ObjectiveTo explore the association between smoking and cognitive functioning in bipolar disorder and schizophrenia.MethodsObservational study. We analyzed data from 184 participants in 3 groups (61 healthy controls, 47 euthymic patients with bipolar-I disorder, 76 patients with clinically stable schizophrenia) assessed by a neuropsychological battery. Statistical analysis was performed comparing subgroups of smokers and non-smokers data. Both groups were demographic and clinically comparable.ResultsSmoking rate was higher in participants with bipolar disorder and schizophrenia (X 2 = 26.8, p = 0.001). Bipolar Group: neuropsychological performance was similar in smokers (n = 28) and non-smokers (n = 19) except perseverative errors of the Wisconsin test, in which smokers performed significantly worse (t = −2.1, p = 0,03). Schizophrenia group: smokers (n = 46) performed significantly better than non-smokers (n = 30) in the verbal fluency test (t = −2.46, p = 0.046), finger tapping right (t = −2.19; p = 0.03) and immediate (t = −2.84, p = 0.006) and delayed recall (t = −2.59, p = 0.01) of Rey figure test.ConclusionsThis is the first study comparing these clinical groups. The global cognitive function in euthymic state was similar in both groups despite of smoking status. However, smoking could be associated with a worse executive function in bipolar disorder. In patients with schizophrenia smoking was associated with better performance in visual memory, verbal fluency and motor speed, but not attention.

A 2-year naturalistic study on cognitive functioning in bipolar disorder

Cognitive alterations in bipolar disorder may reflect genetic influence. However, to what degree mood, medication, thyroid function and other factors impact on longitudinal cognitive functioning remains unclear. A group of patients with bipolar (spectrum) disorder (n = 76) underwent two monthly cognitive assessments over a 2-year period in a prospective, repeated measures design. Regression models were used to investigate associations with predictors, corrected for multiple testing. Patients with bipolar disorder performed worse than healthy controls (n = 61) on all cognitive domains tested. Effect sizes were small, with a maximum of -0.36 for sustained attention. However, cognitive performance varied substantially over the 2-year follow-up, co-varying with subjective cognitive complaints and impacting on functioning. Alterations in sustained attention and motor speed were the only impairments that were invariant over time. Predictors had very limited explanatory power on temporal variation in cognition. Use of second-generation antipsychotics was associated with the largest negative effects on cognition, which were evident in the areas of motor speed and basic information processing (-0.35 < β < -0.5). Cognitive function in bipolar disorder varies significantly over time, largely independent of clinical factors. The temporal stability of sustained attention is the exception, suggesting it may represent a possible candidate intermediary phenotype.

Clinical implications of cognitive function in bipolar disorder

In recent years there has been increased interest in cognitive function in bipolar disorder (BD) as a means of understanding and exploring biological mechanisms relating to predisposition, disease expression and outcome. Despite significant methodological differences between studies we can begin to discern meaningful patterns from existing data. The evidence reviewed suggests that: (a) premorbid cognitive dysfunction is not a dominant feature of BD; in contrast to other severe psychiatric conditions, enhanced cognitive function may be a risk marker for BD; (b) in BD patients with established syndromal disease, trait-related cognitive impairment is reliably seen in the speed of information processing, verbal Learning and memory and response inhibition; (c) cognitive function appears to remain stable post-disease onset in the majority of patients although the risk of dementia in old age is increased; (d) cognitive impairment is a key predictor of functional outcome in BD. These findings underscore the importance of cognition in BD as a marker of neural integrity across all phases of the illness and as a therapeutic target in disability reduction.

COGNITIVE IMPAIRMENT AMONG OLDER ADULTS WITH LATE-LIFE SCHIZOPHRENIA OR BIPOLAR DISORDER

Neurologists are increasingly faced with the daunting task of disentangling dementia from primary psychiatric conditions or recognizing their coexistence in older patients. Both schizophrenia and bipolar disorder are characterized by substantial intergroup cognitive heterogeneity among older and younger patients. In schizophrenia, deficits in many cognitive domains are common; however, "rapid forgetting," loss of crystallized knowledge, and greater than age-normal declines in cognitive function are rare and warrant careful evaluation for secondary causes. The cognitive deficits associated with bipolar disorder tend be most severe during acute affective episodes, but some deficits tend to persist even during periods of relative euthymia. Lifetime number of affective episodes in bipolar disorder may adversely affect cognitive functions in bipolar disorder, but severe deficits and/or substantive declines over a period of a few years are unusual and warrant careful evaluation for secondary causes.

Neurocognitive Endophenotypes for Bipolar Disorder Identified in Multiplex Multigenerational Families

Although genetic influences on bipolar disorder are well established, localization of genes that predispose to the illness has proven difficult. Given that genes predisposing to bipolar disorder may be transmitted without expression of the categorical clinical phenotype, a strategy for identifying risk genes is to identify and map quantitative intermediate phenotypes or endophenotypes. To adjudicate neurocognitive endophenotypes for bipolar disorder. All participants underwent diagnostic interviews and comprehensive neurocognitive evaluations. Neurocognitive measures found to be heritable were entered into analyses designed to determine which test results are impaired in affected individuals, are sensitive to the genetic liability for the illness, and are genetically correlated with affection status. Central valley of Costa Rica; Mexico City, Mexico; and San Antonio, Texas. Seven hundred nine Latino individuals participated in the study. Of these, 660 were members of extended pedigrees with at least 2 siblings diagnosed as having bipolar disorder (n = 230). The remaining subjects were community control subjects drawn from each site who did not have a personal or family history of bipolar disorder or schizophrenia. Neurocognitive test performance. Two of the 22 neurocognitive variables were not significantly heritable and were excluded from subsequent analyses. Patients with bipolar disorder were impaired on 6 cognitive measures compared with nonrelated healthy controls. Nonbipolar first-degree relatives were impaired on 5 of these, and the following 3 tests were genetically correlated with affection status: Digit Symbol Coding Task, Object Delayed Response Task, and immediate facial memory. This large-scale extended pedigree study of cognitive functioning in bipolar disorder identifies measures of processing speed, working memory, and declarative (facial) memory as candidate endophenotypes for bipolar disorder.

Neurocognitive functioning in bipolar disorder.

Neuropsychological processes may have direct bearing on the emotional dysregulation and functional impairments characteristic of bipolar disorder. Neuropsychological deficits that have been identified in adults and children with bipolar disorder include impairments in executive functions, declarative memory, attentional processes, and possibly working memory. Structural and functional magnetic resonance imaging and magnetic resonance spectroscopy studies of adults and children with bipolar disorder also indicate abnormalities in regions thought to underlie these neuropsychological deficits, including the basal ganglia, amygdala, and dorsolateral, orbitofrontal, and anterior cingulate cortices. Study of this area is made challenging by the heterogeneity of bipolar disorder, the heterogeneity of neuropsychological deficits among groups of patients with different clinical characteristics, the lack of specificity of neurocognitive deficits for bipolar disorder, and difficulty ascertaining whether deficits are inherent in the disorder, predate the disorder, or are influenced by mood state, course, treatment, and comorbidity with other disorders. In this review, we integrate the literature on neuropsychological functioning and neuroimaging in both children and adults with bipolar disorder, propose a nascent integrative model of cognitive function in bipolar disorder, and make suggestions for future studies and model development.

The duration of inpatient admission predicts cognitive functioning at discharge in patients with bipolar disorder

Previous studies of cognitive functioning in bipolar disorder generally indicate that a more severe course of illness is associated with greater cognitive impairment. In particular, a history of greater number and longer duration of mood episodes predicts enduring cognitive deficits in euthymic patients. Shifting the focus of this investigation to the cognitive effects of a discrete mood episode, the current study aimed to explore whether patients who require a longer hospitalization to stabilize from an acute episode of mood disturbance present with more compromised cognitive functioning during the phase of early recovery. For this purpose, the study examined the link between the duration of inpatient admission and neuropsychological test scores at the time of discharge in 41 patients with bipolar disorder. Participants were assigned to long (n = 20) and short (n = 21) stay groups using a median split (M = 12). Results indicated that longer admissions were associated with more severe deficits in executive functioning at discharge after controlling for residual mood symptoms and previous number of psychiatric admissions. Findings from the current study may inform discharge planning for patients with bipolar disorder after an extended hospital stay.

Relation between cigarette smoking and cognitive function in euthymic individuals with bipolar disorder

Background Individuals with bipolar disorder have higher rates of cigarette smoking and cognitive deficits when compared to the general population. Emerging evidence indicates that both smoking and cognitive deficits are associated with more severe illness presentation and course. Methods The data were derived from a study evaluating a novel treatment for cognitive function in bipolar disorder. Smoking status was determined by self-report; cognitive function was evaluated with a comprehensive cognitive battery, which included measures of psychomotor speed, attention, memory, learning and executive function. The relations between smoking status and cognitive measures were evaluated with two independent-samples t-test and multiple regression. Results The sample comprised forty-three subjects with bipolar disorder (Type I/II). There were no consistent differences in neuropsychological performance between current smokers ( N = 16) and non-smokers ( N = 27) on most tasks. The occurrence of subjective cognitive failures, as measured with the Cognitive Functioning Questionnaire, was non-significantly lower for smokers compared to non-smokers. Lifetime “smoking load” was negatively associated with premorbid intelligence as estimated by the National Adult Reading Test. Conclusion This pilot study provides preliminary evidence that cigarette smoking may exert a salutary effect on subjective, but not objective, measures of cognitive function in euthymic bipolar patients. A larger sample size evaluating this hypothesis would be less vulnerable to type II error.