Valpromide increases amplitude of heart rate circadian rhythm in remitted bipolar and unipolar disorders. A placebo-controlled study

Safety and tolerability of anticonvulsant medication in bipolar disorder

INTRODUCTION

Anticonvulsants (AC) are widely used and recommended as a treatment option in different phases of bipolar disorder (BD). In contrast to ample evidence for efficacy in acute mania, there is generally less unambiguous evidence for maintenance treatment or bipolar depression, and data on long-term tolerability in BD are sparse, although this varies greatly between different compounds. This review summarizes the clinically relevant tolerability and safety profile of ACs commonly used for the treatment of BD based on findings from randomized controlled trials (RCT).

AREAS COVERED

Systematic search of the English literature between January 1991 and May 2015 revealed a total of nine RCTs investigating valproate, five RCTs with carbamazepine and 8 with lamotrigine For these ACs we found information on side effect profiles for both acute and maintenance RCTs, albeit of varying quality, whereas for topiramate (five RCTs), gabapentin and esclicarbazepine acetate (one RCT each) only acute treatment RCTs have been published. Descriptive side effect profiles from open-label studies exist for several other ACs rarely used in BD, and are included in this review as a brief narrative chapter.

EXPERT OPINION

Whereas both valproate and carbamazepine are associated with, in part, severe adverse events, lamotrigine emerges as a relatively safe and well tolerated treatment option, especially in maintenance treatment and prevention of depressive relapse in BD. Lack of proven efficacy and side effect profile of other, less rigorously studied ACs restricts their use only to very selected BD cases.

Valnoctamide as a valproate substitute with low teratogenic potential in mania: a double-blind, controlled, add-on clinical trial

OBJECTIVES

Valproic acid's well-known teratogenicity limits its use in women of childbearing age. Valnoctamide is an analog of valproate that does not undergo biotransformation to the corresponding free acid. In mice, valnoctamide has been shown to be distinctly less teratogenic than valproate. Valnoctamide is an anticonvulsant, and we hypothesized that valnoctamide is antimanic.

METHODS

We performed a double-blind, five-week, add-on, controlled trial of valnoctamide in mania. Patients were treated with risperidone at doses of the physician's discretion. Valnoctamide or placebo was begun at doses of 600 mg/day and increased to 1200 mg after four days. Weekly ratings by a psychiatrist blind to the study drug were conducted using the Brief Psychiatric Rating Scale (BPRS), the Young Mania Rating Scale (YMRS), and the Clinical Global Impression (CGI).

RESULTS

Fifteen valnoctamide patients and 17 placebo patients completed at least one post-baseline week and were included in data analysis. In all efficacy measures valnoctamide was more effective than placebo as an add-on to risperidone, using two-way analysis of variance (ANOVA) with time as the within-subject factor. Two-way ANOVA showed a significant effect of time (p < 0.001) and significant interaction between treatment and time (YMRS: p = 0.012; BPRS: p = 0.007; CGI: p = 0.003). Differences between valnoctamide and placebo were significant from week 3 to week 5.

CONCLUSION

Valnoctamide could be an important valproate substitute for women of childbearing age with bipolar disorder who may become pregnant.

A new potential marker for abnormal cardiac physiology in depression

The purpose of the study was to determine if a nonlinear estimate of dimensional complexity, Pointwise correlation dimension (Pd2), could be used to identify abnormal cardiac physiology associated with depression in primary care outpatients. The subjects were 22 medical controls and 30 general medical outpatients with depression who wore a cardiac monitor for 24 h. There was a significant difference between depressed and control subjects for Pd2 based on the entire cardiac time-series, with depressed subjects exhibiting higher Pd2 values. A cutoff score reflecting high dimensional complexity was selected, and an odds ratio was calculated demonstrating that patients with Pd2 values above the cut-off were 8.8 times more likely to fall in the depressed group than the control group. Additional research is needed to determine if Pd2 is useful for identifying physiological markers of depression.

Self-organizing neural network analyses of cardiac data in depression

OBJECTIVE

To determine if an unsupervised self-organizing neural network could create a clinically meaningful distinction of 'depression' versus 'no depression' based on cardiac time-series data.

DESIGN

A self-organizing map (SOM) was used to separate the time-series of 84 subjects into groups based on characteristics of the data alone.

MATERIALS AND METHODS

Analyses included natural log transformations and two types of filtering to enhance characteristics of the data as well as classifications of unprocessed data. A Pearson chi(2) analysis was performed to determine if the SOM groups bore any relation to the binary clinical groups.

RESULTS

Overall correct SOM classifications ranged from 54 to 70.2% with two classifications being clinically meaningful.

CONCLUSIONS

SOM classifications of cardiac time-series data with enhanced ultradian variations and cardiac data recorded around the interval when a person was in bed were useful in differentiating clinically meaningful subgroups with and without depression.

Search for a common mechanism of mood stabilizers

Manic-depression, or bipolar affective disorder, is a prevalent mental disorder with a global impact. Mood stabilizers have acute and long-term effects and at a minimum are prophylactic for manic or depressive poles without detriment to the other. Lithium has significant effects on mania and depression, but may be augmented or substituted by some antiepileptic drugs. The biochemical basis for mood stabilizer therapies or the molecular origins of bipolar disorder is unknown. One approach to this problem is to seek a common target of all mood stabilizers. Lithium directly inhibits two evolutionarily conserved signal transduction pathways. It both suppresses inositol signaling through depletion of intracellular inositol and inhibits glycogen synthase kinase-3 (GSK-3), a multifunctional protein kinase. A number of GSK-3 substrates are involved in neuronal function and organization, and therefore present plausible targets for therapy. Valproic acid (VPA) is an antiepileptic drug with mood-stabilizing properties. It may indirectly reduce GSK-3 activity, and can up-regulate gene expression through inhibition of histone deacetylase. These effects, however, are not conserved between different cell types. VPA also inhibits inositol signaling through an inositol-depletion mechanism. There is no evidence for GSK-3 inhibition by carbamazepine, a second antiepileptic mood stabilizer. In contrast, this drug alters neuronal morphology through an inositol-depletion mechanism as seen with lithium and VPA. Studies on the enzyme prolyl oligopeptidase and the sodium myo-inositol transporter support an inositol-depletion mechanism for mood stabilizer action. Despite these intriguing observations, it remains unclear how changes in inositol signaling underlie the origins of bipolar disorder.