Drugs under early investigation for the treatment of bipolar disorder

Advances in the management of bipolar disorder in children and adolescents: an update on the literature

INTRODUCTION

Early diagnosis and treatment concerning bipolar disorder (BD) are related to a better functioning over the long-term period. Although pharmacotherapy is indicated for approximately all youths with BD, nearly one-third of patients do not receive adequate medications for their condition.

AREAS COVERED

The authors discuss the available scientific evidence from the current literature about the management of BD in both children and adolescents, giving particular focus to the efficacy and tolerability of the available pharmacological agents. Studies were identified searching MEDLINE and retrieved from reference listings of relevant articles and through consultation with experts in the field.

EXPERT OPINION

Many D2-blockers, approved by the Food and Drug Administration (FDA) based on their antimanic properties in youths, are related to both short- and long-term side effects. Lurasidone was found to be effective for the treatment of acute juvenile bipolar depression, while lithium for the treatment and recurrence prevention of manic/mixed episodes. The most common anticonvulsants were found to be most useful as adjunctive antimanic agents in non-responders to first-line monotherapies. No data was found to support the use of antidepressants in juvenile BD.

A Randomized, Double-Blind, Controlled Clinical Trial of Omega-3 Fatty Acids and Inositol as Monotherapies and in Combination for the Treatment of Pediatric Bipolar Spectrum Disorder in Children Age 5-12

Objectives

The aim of this study was to assess the efficacy and tolerability of omega-3 fatty acids (FAs) and inositol alone and in combination for the treatment of pediatric bipolar (BP) spectrum disorder in young children.

Methods

Participants were male and female children ages 5-12 meeting DSM-IV diagnostic criteria for a BP spectrum disorder and displaying mixed, manic, or hypomanic symptoms without psychotic features at the time of evaluation.

Results

Participants concomitantly taking psychotropic medication were excluded from efficacy analyses. There were significant reductions in YMRS and HDRS mean scores in the inositol and combination treatment groups (all p < 0.05) and in CDRS mean scores in the combination treatment group (p < 0.001), with the largest changes seen in the combination group. Those receiving the combination treatment had the highest rates of antimanic and antidepressant response. The odds ratios for the combination group compared to the omega-3 FAs and inositol groups were clinically meaningful (ORs ≥2) for 50% improvement on the YMRS, normalization of the YMRS (score <12) (vs. inositol group only), 50% improvement on the HDRS, 50% improvement on CDRS (vs. omega-3 FAs group only), and CGI-I Mania, CGI-I MDD, and CGI-I Anxiety scores <2.

Conclusion

The antimanic and antidepressant effects of the combination treatment of omega-3 FAs and inositol were consistently superior to either treatment used alone. This combination may offer a safe and effective alternative or augmenting treatment for youth with BP spectrum disorder, but more work is needed to confirm the statistical significance of this finding.

Aspirin and celecoxib may help to rectify a neurotransmission imbalance in bipolar disorder

BACKGROUND

Mood stabilizers with disparate chemical structures are approved for treating bipolar disorder, but their mechanisms of action are not agreed on. However, when administered to unanesthetized rats at clinically relevant doses, they modulate neurotransmission involving arachidonic acid and brain activity of COX-2, which oxidizes arachidonic acid within the arachidonic acid metabolic cascade.

HYPOTHESIS

Inhibiting COX-2 directly might enhance mood stabilizer effects in bipolar disorder patients.

OBSERVATIONS

This paper reviews randomized controlled trials that showed that celecoxib, a selective COX-2 inhibitor, or low-dose aspirin, which inhibits COX-1 and inhibits/acetylates COX-2, reduced bipolar symptoms in patients on mood stabilizers. More convincing are two population based pharmacoepidemiological studies that each demonstrated that chronic low dose aspirin reduced bipolar severity markers in patients on mood stabilizers.

CONCLUSIONS

This clinical evidence is consistent with the hypothesis that low-dose chronic aspirin and celecoxib, which can inhibit COX-2 and enter brain, can be repurposed in bipolar disorder to enhance mood stabilizer effects on arachidonic acid metabolism and neurotransmission.

Role of epigenetic regulatory enzymes in animal models of mania induced by amphetamine and paradoxical sleep deprivation

It is known that bipolar disorder has a multifactorial aetiology where the interaction between genetic and environmental factors is responsible for its development. Because of this, epigenetics has been largely studied in psychiatric disorders. The present study aims to evaluate the effects of histone deacetylase inhibitors on epigenetic enzyme alterations in rats or mice submitted to animal models of mania induced by dextro-amphetamine or sleep deprivation, respectively. Adult male Wistar rats were subjected to 14 days of dextro-amphetamine administration, and from the eighth to the fourteenth day, the animals were treated with valproate and sodium butyrate in addition to dextro-amphetamine injections. Adult C57BL/6 mice received 7 days of valproate or sodium butyrate administration, being sleep deprived at the last 36 hr of the protocol. Locomotor and exploratory activities of rats and mice were evaluated in the open-field test, and histone deacetylase, DNA methyltransferase, and histone acetyltransferase activities were assessed in the frontal cortex, hippocampus, and striatum. Dextro-amphetamine and sleep deprivation induced hyperactivity and increased histone deacetylase and DNA methyltransferase activities in the animal's brain. Valproate and sodium butyrate were able to reverse hyperlocomotion induced by both animal models, as well as the alterations on histone deacetylase and DNA methyltransferase activities. There was a positive correlation between enzyme activities and number of crossings for both models. Histone deacetylase and DNA methyltransferase activities also presented a positive correlation between theirselves. These results suggest that epigenetics can play an important role in BD pathophysiology as well as in its treatment.

Motor Transitions' Peculiarity of Heterozygous DAT Rats When Offspring of an Unconventional KOxWT Mating

Causal factors of psychiatric diseases are unclear, due to gene × environment interactions. Evaluation of consequences, after a dopamine-transporter (DAT) gene knock-out (DAT-KO), has enhanced our understanding into the pathological dynamics of several brain disorders, such as Attention-Deficit/Hyperactivity and Bipolar-Affective disorders. Recently, our attention has shifted to DAT hypo-functional (heterozygous, HET) rodents: HET dams display less maternal care and HET females display marked hypo-locomotion if cared by HET dams (Mariano et al., 2019). We assessed phenotypes of male DAT-heterozygous rats as a function of their parents: we compared "maternal" origin (MAT-HET, obtained by breeding KO-male rats with WT-female dams) to "mixed" origin (MIX-HET, obtained by classical breeding, both heterozygous parents) of the allele. MAT-HET subjects had significantly longer rhythms of daily locomotor activity than MIX-HET and WT-control subjects. Furthermore, acute methylphenidate (MPH: 0, 1, 2 mg/kg) revealed elevated threshold for locomotor stimulation in MAT-HETs, with no response to the lower dose. Finally, by Porsolt-Test, MAT-HETs showed enhanced escape-seeking (diving) with more transitions towards behavioral despair (floating). When comparing both MAT- and MIX-HET to WT-control rats, decreased levels of DAT and HDAC4 were evident in the ventral-striatum; moreover, with respect to MIX-HET subjects, MAT-HET ones displayed increased DAT density in dorsal-striatum. MAT-HET rats displayed region-specific changes in DAT expression, compared to "classical" MIX-HET subjects: greater DAT availability may elevate threshold for dopamine action. Further behavioral and epigenetic characterizations of MAT-HETs, together with deeper characterization of maternal roles, could help to explore parent-of-origin mechanisms for such a peculiar phenotype.

The preclinical discovery and development of quetiapine for the treatment of mania and depression

INTRODUCTION

Bipolar disorder is a chronic disabling condition characterized by alternating manic and depressive episodes. Bipolar disorder has been associated with functional impairment, poor quality of life, morbidity and mortality. Despite its significant clinical, social and economic burden, treatment options for bipolar disorder are still limited. Several clinical trials have shown efficacy of the atypical antipsychotic quetiapine (QTP) in the treatment of this condition. However, the mechanisms underlying the antidepressant and anti-manic effects of QTP remain poorly understood. Areas covered: The article provides the emerging evidence from pre-clinical studies regarding the antidepressant and anti-manic mechanisms of action of QTP. In combination with its primary active metabolite norquetiapine, QTP modulates several neurotransmitter systems, including serotonin, dopamine, noradrenaline and histamine. QTP also seems to influence mediators of the immune system. Expert opinion: Pre-clinical studies have provided valuable information on the potential antidepressant mechanisms of action of QTP, but pre-clinical studies on QTP's anti-manic effects are still scarce. A major problem refers to the lack of valid experimental models for bipolar disorder. Additionally, immune and genetic based studies are largely descriptive. The role of the QTP metabolite norquetiapine in modulating non-neurotransmitter systems also needs to be further addressed.