Rafael Tabarés-Seisdedos

Functioning and Disability in Bipolar Disorder: An Extensive Review

Background: Bipolar disorder has generally been regarded as having a better functional outcome than schizophrenia. However, studies have suggested low functioning in bipolar patients even when they are in clinical remission. Our aim was to determine the degree of functioning and disability in bipolar patients. Secondly, we reviewed factors potentially associated with the low functioning of bipolar patients. Method: The authors conducted an extensive Medline and Pubmed search of the published literature from 1980 up to December 2007, using a variety of search terms to find relevant articles. Bibliographies of retrieved papers were further analysed for publications of interest. Articles that reported clinically significant findings on functioning and disability, and research reports were reviewed in detail. Results: From these articles, we determined that bipolar disorder is associated with significant impairment in work, family and social life, beyond the acute phases of the illness. The aspects that appear to increase the risk of low functioning and disability in bipolar patients are mainly subsyndromal symptoms and neurocognitive impairment, among others. Conclusions: Suitable pharmacological and psychological interventions may improve the level of functioning and reduce the disability in bipolar patients. Potential targets to be considered for intervention should be residual symptoms, comorbid conditions and neurocognitive deficits. Further research is required to better identify the factors that best predict functioning in bipolar patients.

Neurocognitive and clinical predictors of functional outcome in patients with schizophrenia and bipolar I disorder at one-year follow-up.

OBJECTIVE Many studies have reported that cognitive ability may be predictive of the functional outcome for patients with schizophrenia. However, no study has prospectively examined these aspects in schizophrenia and bipolar disorders simultaneously. The present study attempted to analyze if neurocognition and clinical status predicts the real-life functioning for patients with schizophrenia or bipolar I disorder, using a longitudinal design. METHOD Forty-seven schizophrenic and 43 bipolar I outpatients were assessed twice with a neurocognitive battery (Executive Functions, Working Memory, Verbal Memory, Visual Memory, Visual-Motor Processing, Vigilance, Vocabulary and Motor Speed tasks), clinical scales (the Positive and Negative Symptom Scale, the Hamilton Rating Scale for Depression and the Clinician Administered Rating Scale for Mania) and functional outcome measures (the Global Assessment of Functioning Scale, the WHOs Disability Assessment Scale and occupational adaptation level) over a one-year follow-up period. The cognitive performance of the patients was compared, at baseline and one year later, with that of 25 healthy subjects. RESULTS In schizophrenia patients, global functioning one year later was predicted by a composite neurocognitive score and three specific domain (verbal memory, motor speed, vocabulary). Symptoms appeared to explain less of the variance in functioning. In bipolar I patients, changes in the composite neurocognitive score over one year, deficits in the visual/motor processing domain, severity of symptoms (psychotic, excitatory and affective symptoms) and premorbid adjustment at the first assessment were the variables that better predicted functioning or disability changes over follow-up period. CONCLUSIONS Although the relationships between cognition, symptoms and functional capacity differ for schizophrenia or bipolar I patients, neuropsychological performance seems to be a principal longitudinal predictor of functioning in both disorders. Baseline neurocognition and cognitive changes over 12 months predicted changes in functioning over the same period, but only in bipolar I patients. These cognitive domains could be potential neurocognitive endophenotypes (endophenocognitypes) with regard to bipolar I disorder.

Neurocognitive endophenotypes (Endophenocognitypes) from studies of relatives of bipolar disorder subjects: A systematic review

BACKGROUND There is growing interest to research neurocognition as a putative endophenotype for subjects with bipolar disorders (BD). The authors sought to review the available literature focused on relatives of subjects with bipolar disorder (BD-Rels) and identify suitable cognitive candidates to endophenotypes or endophenocognitypes. METHOD A systematic review was conducted in Medline, EMBASE and PsycINFO databases (1980-July 2007), supplemented with a manual search of reference lists. RESULTS Twenty-three cross-sectional papers of discordant twins (4 studies), genetic high-risk subjects (7), and different BD-Rel groups (12) met the inclusion criteria and evaluated 532 BD-Rels. Impairments on the broad domain of verbal learning/memory were found in 6 out of 11 studies (54%), as well as in 3 of 9 reports (33%) of working memory. Moreover, BD-Rels showed deficits in visual-spatial learning and memory (1/6 reports; 17%), alternating attention (1/8; 12.5%), psychomotor speed (2/10; 20%), and abstraction/cognitive flexibility, sustained attention and selective attention (2/8 each; 25%). Scores of general intelligence were lower than those of controls in 2/16 (12.5%) reports, but fell well within the average range in all studies. No study that assessed immediate memory or verbal fluency (6 each) reported impairments in BD-Rels. Finally, language, social cognition, and motor and planning skills are neglected areas of research. CONCLUSIONS Overall, the neurocognitive profile in BD-Rels is still unclear, and the evidence in support of the presence of cognitive deficits seems quite sparse. Verbal learning/memory and verbal working memory seem to be the most suitable endophenocognitypes for BD. Conversely, healthy family members would have an intact performance on immediate memory, verbal fluency, and probably on general intelligence. The possibility that BD-Rels show less cognitive efficiency compared to healthy controls also on other functions must be addressed by future studies with larger samples, comprehensive neuropsychological assessments, and, ideally, longitudinal designs.

Specificity of cognitive deficits in bipolar disorder versus schizophrenia. A systematic review.

Background: More and more epidemiological, genetic and neuroimaging studies show similarities between bipolar disorder (BD) and schizophrenia (SZ). Cognitive functions are known to be highly impaired in SZ and are increasingly studied in BD. When both populations are compared, the conclusions appear to be contradictory. The purpose of this review is to help define the profile of cognitive deficits in BD and in SZ. Methods: A systematic review of the literature of neuropsychological studies comparing BD and SZ was made, beginning in January 1990 and ending in January 2005. Thirty-eight studies met the required quality criteria and were included in this review. Results: Bipolar patients exhibit extensive cognitive abnormalities with a pattern of deficits that is not unique to this disease. However, when compared to schizophrenic patients, bipolar patients demonstrate a lesser degree of deficits, particularly concerning premorbid and current intelligence quotient and perhaps attention, verbal memory and executive functions. When looking into effect sizes, there seem to be different profiles even in studies finding no significant differences. Conclusions: The neuropsychological differences reported between both groups could be due to the presence of psychotic features, to environmental factors (stressful events, duration of the disease and number of hospitalisations) and could also be related to differences during the neurodevelopmental phase. Further studies should confirm whether these results are truly related to different neurobiological backgrounds.

Efficacy of Functional Remediation in Bipolar Disorder: A Multicenter Randomized Controlled Study

OBJECTIVE The authors sought to assess the efficacy of functional remediation, a novel intervention program, on functional improvement in a sample of euthymic patients with bipolar disorder. METHOD In a multicenter, randomized, rater-blind clinical trial involving 239 outpatients with DSM-IV bipolar disorder, functional remediation (N=77) was compared with psychoeducation (N=82) and treatment as usual (N=80) over 21 weeks. Pharmacological treatment was kept stable in all three groups. The primary outcome measure was improvement in global psychosocial functioning, measured blindly as the mean change in score on the Functioning Assessment Short Test from baseline to endpoint. RESULTS At the end of the study, 183 patients completed the treatment phase. Repeated-measures analysis revealed significant functional improvement from baseline to endpoint over the 21 weeks of treatment (last observation carried forward), suggesting an interaction between treatment assignment and time. Tukeys post hoc tests revealed that functional remediation differed significantly from treatment as usual, but not from psychoeducation. CONCLUSIONS Functional remediation, a novel group intervention, showed efficacy in improving the functional outcome of a sample of euthymic bipolar patients as compared with treatment as usual.

Persistent Cognitive Dysfunctions in Bipolar I Disorder and Schizophrenic Patients: A 3-Year Follow-Up Study

Background: Neurocognitive impairment has consistently been considered a central and stable feature in schizophrenia. As this possibility has been far less studied in bipolar disorder, we aimed to prospectively investigate the stability and specificity of cognitive performance in bipolar disorder compared to schizophrenia. Methods: Fifteen DSM-IV bipolar type I patients and 15 schizophrenic patients were assessed twice with a comprehensive neuropsychological battery and the Positive and Negative Syndrome Scale over a 3-year follow-up. The cognitive performance of the groups was compared at baseline and 3 years later as a mean with that of 26 healthy volunteers. Endpoint and baseline assessments were also compared for each patient group in order to evaluate the stability of cognitive impairment. Results: At both time points, bipolar and schizophrenic patients showed significant deficits on most of the cognitive tasks compared to healthy subjects. Overall, the cross-sectional cognitive profile was similar for both patient groups. Moreover, after controlling for age and length of illness, the two groups’ cognitive function did not differ over time in any test. With the exception of the Stroop color-word interference task, performance at baseline for each test but neither length of illness nor diagnostic category predicted the endpoint performance. Conclusion: This preliminary study suggests that cognitive impairment is also mainly stable over time in bipolar I disorder and thus not specific to schizophrenia.

Neurocognition in bipolar disorders—A closer look at comorbidities and medications

The last decade has witnessed a growing interest in the neuropsychological study of bipolar disorder (BD). This chronic mood disorder is associated with persistent neurocognitive impairments even during periods of euthymia, particularly in the broad domains of attention, verbal memory and executive functions. More interestingly, cognitive dysfunction seems to predict a poorer functional outcome among BD patients and thus represents an important target for future therapies. The aetiology of cognitive dysfunction is probably multifactorial, including gene-environment interactions with potentially confounding variables as well. Drug-induced cognitive adverse effects represent an important and difficult to examine confounder. This review provides an overview of selected aspects of neurocognition in bipolar disorder with a focus on the relative contributions of medications as well as medical and psychiatric comorbid conditions to cognitive dysfunction. Finally, recommendations for future research in the field are provided including collaborative studies with larger samples, observational follow-up studies, as well as randomized clinical trials comparing head-to-head the neurocognitive impact of different medications.

Long-term outcome of cognitive impairment in bipolar disorder.

OBJECTIVE To evaluate the longitudinal course and outcome of cognitive deficits and their clinical correlates in bipolar disorder. METHOD One hundred thirteen participants (68 patients and 45 healthy controls) were assessed by the means of a neuropsychological battery targeting attention, psychomotor speed, verbal memory, and executive functions at baseline: 68 euthymic outpatients with a DSM-IV diagnosis of bipolar disorder (53 bipolar I and 15 bipolar II) were enrolled at the Bipolar Disorder Unit of the Hospital Clinic of Barcelona. Forty-five patients completed the follow-up. The assessments started in February 1999 and finished in July 2010. The primary outcome of the study was the change in the neuropsychological performance in the patient group. RESULTS Repeated-measures analyses showed significant effects of time in 2 cognitive domains: attention and executive functions. Attention slightly improved (P = .043) but executive function worsened (P = .001). Regression analyses showed that the duration of illness and baseline subdepressive symptoms were associated with poor performance in executive function. Subdepressive symptoms at endpoint were associated with poor functioning. The best predictor of low functioning was verbal memory dysfunction at baseline. CONCLUSIONS The cognitive impairment remained stable across the follow-up period in many measures assessed except for a worsening of executive measures, which have been found to be associated with the duration of illness and subdepressive symptoms.

No paradox, no progress: inverse cancer comorbidity in people with other complex diseases

In the past 5 years, several leading groups have attempted to explain why individuals with Downs syndrome have a reduced risk of many solid tumours and an increased risk of leukaemia and testicular cancer. Niels Bohr, the Danish physicist, noted that a paradox could initiate progress. We think that the paradox of a medical disorder protecting against cancer could be formalised in a new model of inverse cancer morbidity in people with other serious diseases. In this Personal View, we review evidence from epidemiological and clinical studies that supports a consistently lower than expected occurrence of cancer in patients with Downs syndrome, Parkinsons disease, schizophrenia, diabetes, Alzheimers disease, multiple sclerosis, and anorexia nervosa. Intriguingly, most comorbidities are neuropsychiatric or CNS disorders. We provide a brief overview of evidence indicating genetic and molecular connections between cancer and these complex diseases. Inverse comorbidity could be a valuable model to investigate common or related pathways or processes and test new therapies, but, most importantly, to understand why certain people are protected from the malignancy.

Treatment nonadherence and neurocognitive impairment in bipolar disorder.

OBJECTIVE Little is known regarding the relationship between treatment adherence and residual cognitive dysfunction in euthymic bipolar disorder patients. This study aimed to investigate whether poor treatment adherence is associated with cognitive impairment in euthymic bipolar patients and whether other factors may be associated with both adherence and cognitive functioning. METHOD Euthymic DSM-IV bipolar I or II disorder patients (N = 103: 61 with high levels of treatment adherence and 42 with poor treatment adherence) were assessed using a neuropsychological battery targeting attention, psychomotor speed, verbal memory, and executive functions and compared with 35 healthy controls of similar age, sex distribution, and education. Data were collected from September 2005 to June 2007. RESULTS Bipolar patients with poor treatment adherence had more hospitalizations than those with high adherence. After controlling for age, gender, estimated IQ score, and Young Mania Rating Scale and 17-item Hamilton Rating Scale for Depression scores, non-treatment-adherent patients performed less well than normal controls in verbal learning and some executive functions. Among treatment-adherent and poorly adherent bipolar disorder patients, performance was similar in attention tasks and short-term and long-term verbal recall, but non-treatment-adherent patients were more impaired in ability to inhibit interferences and in spatial working memory. Poorer treatment adherence also was associated with the bipolar I subtype and with greater illness severity, as indicated by number of manic episodes and hospitalizations and history of psychosis. Pharmacologic factors, such as treatment with lithium, may also influence the relationship between neurocognition and adherence. CONCLUSIONS There is a close relationship between poor treatment adherence and cognitive impairment, but the causal inferences of these findings are uncertain. Poor treatment adherence may worsen the course of bipolar disorder and so indirectly worsen cognitive performance, or cognitive impairment may contribute to poor treatment adherence and reflect more severe illness.