Association of cognitive deficits with elevated homocysteine levels in euthymic bipolar patients and its impact on psychosocial functioning: preliminary results

OBJECTIVES

Elevated homocysteine (Hcy) levels have been demonstrated to have a negative impact on cognitive functioning in healthy elderly people. Further studies suggest that they are an independent risk factor for dementia, in particular for Alzheimer's disease. Bipolar disorder is also associated with cognitive impairment. However, the pathophysiological mechanisms of these deficits have not been elucidated yet. This study examines the role of Hcy on cognition and its impact on psychosocial functioning in euthymic bipolar patients.

METHODS

A total of 55 euthymic bipolar patients and 17 healthy controls were enrolled in the study. Neuropsychological assessments consisted of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the Trail Making Test (TMT), the Weschler Adult Intelligence Scale, 3(rd) edition (WAIS-III) subtest Letter-Number Sequencing Test (LNST) and the HAWIE-R (German version of the WAIS-R) subtest Information. Psychosocial functioning was assessed using the Social Adjustment Scale (SAS). To obtain plasma levels of Hcy, blood samples were collected in EDTA tubes, immediately put on ice, centrifuged within 15 min and stored at -80 degrees C. Total Hcy concentration was measured using high-performance liquid chromatography.

RESULTS

In the neuropsychological tests, patients differed significantly from healthy controls on the TMT B and the RBANS composite indices Language, Attention and Total Score. No differences were found on the HAWIE-R subtest Information, the TMT A, LNST or the RBANS composite indices Immediate Memory, Visuospatial/Constructional Abilities and Delayed Memory. Mean Hcy levels were 9.8 +/- 3.2 microm/L in the patient group and 7.8 +/- 2.1 microm/L in the control group, respectively (p = 0.012). In the patient group Hcy levels significantly correlated with gender, diagnosis and RBANS index scores for Immediate Memory, Language, Attention and Total Score. Linear regression analyses revealed a significant and independent association of Hcy levels with Immediate Memory and TMT B scores in the patient group. Homocysteine levels did not correlate with any measure in the control group. Spearman's correlations indicated that psychosocial functioning in bipolar patients is not associated with clinical variables apart from time in remission. However, it correlated significantly with working memory measures (LNST). No relationship could be determined between psychosocial functioning and Hcy plasma levels.

CONCLUSIONS

Elevated Hcy levels seem to be associated with cognitive impairment in euthymic bipolar patients, but not with psychosocial functioning. More studies are needed to clarify the role of Hcy in cognition in bipolar disorder.

Risperidone monotherapy in manic inpatients: an open label, multicentre trial

OBJECTIVE

The efficacy of risperidone in acute mania has been established in several controlled clinical studies. However, this may not necessarily resemble the clinical effectiveness of this treatment, as patient populations in controlled studies are considered as being not representative. This study examined risperidone monotherapy in a sample of severe manic patients in admission ward settings.

METHODS

Open label monotherapy with risperidone was examined for 3 weeks in 30 inpatients. Subjects were evaluated with structured clinical rating scales: Young Mania Rating Scale (YMRS), Clinical Global Impression, bipolar version (CGI-BP), and the Extrapyramidal Symptom Rating Scale (ESRS). In addition, the amount of concomitant use of benzodiazepines was documented. Data were analysed using a last observation carried forward method on all subjects given medication at baseline.

RESULTS

Significant improvement from baseline to exit was observed both for the YMRS and CGI-BP. Responder analysis revealed that two-thirds of the patients showed a reduction of 50% in the YMRS score, and 69% of the patients were rated as very much improved or much improved on the CGI-BP mania scale at study exit. Only three patients dropped out due to adverse events, in one case due to extrapyramidal symptoms.

CONCLUSIONS

The efficacy of risperidone in the acute treatment of mania as observed in controlled studies could be replicated in this open monotherapy study in a severely manic inpatient population. Considering the mean maximal dosage of 5.5+/-0.9 mg risperidone, the tolerability and safety profile appeared satisfactory.

Acute antimanic efficacy and safety of oxcarbazepine in an open trial with an on-off-on design

RATIONALE AND OBJECTIVES

Carbamazepine has shown reasonable antimanic properties, but its use has been limited because of enzyme-inducing effects. The keto-derivative oxcarbazepine (OXC) is very similar to carbamazepine, however, the metabolic pathway is different. OXC is not metabolized to the 10, 11-epoxide, which seems to be responsible for several undesirable side-effects of carbamazepine and furthermore OXC has less enzyme-inducing properties.

METHODS

In this non-random open label study, patients were treated with OXC for 14 days, crossed over to no OXC for 7 days, and then crossed back over to OXC for the remaining 14 days. OXC was titrated to a final dose in a range of 900-2100 mg due to individual response. Treatment success was defined as a reduction of the original Young Mania Rating Scale (YMRS) score of more than 50% at the end of study period.

RESULTS

Four of the 12 included patients (33%) met defined response criteria at the end of study period. Fifty percentage of the patients had to be prematurely excluded from the trial. The mean YMRS scores of the on-periods were obviously different from the off-period. Forty-two percentage of the patients experienced side-effects leading to premature discontinuation in two of 12 patients.

CONCLUSION

Antimanic activity of OXC was demonstrated in this pilot study only for patients with mild or moderate manic symptoms. Further studies are encouraged to clarify OXC's role as mood-stabilizer and assess whether it has a profile similar to that of carbamazepine.

[Clinical relevance and treatment possibilities of rapid cycling in patients with bipolar disorder]

In the actual version of the WHO diagnostic guidelines, the ICD-10, subtypes of bipolar disorder are not specified, in contrast to the American DSM-IV, where bipolar disorder has already been differentiated in bipolar I (severe manic and depressive episodes) and bipolar II disorder (depressive and hypomanic episodes). Furthermore, aspects of the longitudinal course of the illness, like rapid cycling (RC), are reflected as well. Rapid cycling is defined as four or more affective episodes within one year of the illness. It has been postulated that rapid cycling is related with a poor response to lithium, to the same extent as mixed episodes or an atypical onset (depressive episode first) of the disease. Here, the current status of alternative pharmacological and supportive therapy of rapid cycling is presented and discussed. Furthermore, the article also displays biological parameters associated with rapid cycling like higher prevalence in women, hypothyreoidism, subtype of bipolar disorder, COMT-allele, influence of sleep or risk of antidepressant induced cycling.