What makes a drug a primary mood stabilizer?

Mood stabilizers for patients with bipolar disorder: the state of the art

Bipolar disorder (BD) is a prevalent and disabling condition, often comorbid with other medical and psychiatric conditions and frequently misdiagnosed. International treatment guidelines for BD recommend the use of mood stabilizers - either in monotherapy or in association - as the gold standard in both acute and long-term therapy. Commonly used in the clinical practice of BD, mood stabilizers have represented an evolving field over the last few years. The concept of stabilization, in fact, has been stressed as the ultimate objective of the treatment of BD, given the chronic and recurrent nature of the illness, which accounts for its significant levels of impairment and disability. To date, different compounds are included within the broad class of mood stabilizers, with lithium, anticonvulsants and, more recently, atypical antipsychotics being the most representative agents. This article is aimed at providing an updated review of the available literature in relation to the role of mood stabilizers in BD, with particular emphasis on their mechanism of action, main clinical aspects and specific use in the different phases of BD treatment, according to the most recently published international treatment guidelines.

Affect regulation in pediatric bipolar disorder

Increasingly, clinicians and researchers alike are describing children presenting with emotional and behavioral problems as suffering from deficits of "affect regulation." The present article reviews the current understanding of affect regulation. The authors also discuss recent findings implicating affect dysregulation in children and adolescents with bipolar disorder.

Six-month prospective life charting of mood symptoms with lamotrigine monotherapy versus placebo in rapid cycling bipolar disorder

BACKGROUND

Fluctuations in mood are quintessential features of bipolar disorder; however, previous studies have seldom examined the extent to which pharmacotherapies for bipolar disorder may reduce or ameliorate daily or weekly mood variability. The anticonvulsant lamotrigine has demonstrated efficacy for relapse prevention in bipolar disorder, but its possible mood-stabilizing properties on a day-to-day or week-to-week basis have not previously been investigated.

METHODS

Weekly mood shifts were examined over 26 weeks using patients' self-reported prospective Life Chart Method (LCM) data obtained as part of a previously reported randomized relapse prevention comparison of lamotrigine monotherapy or placebo in 182 bipolar patients with DSM-IV rapid cycling. Generalized estimating equation (GEE) analyses were used to compare treatment arms for subjects who achieved euthymia across weeks.

RESULTS

After adjusting for potential confounding factors, a final GEE model revealed that subjects taking lamotrigine were 1.8 times more likely than those taking placebo to achieve euthymia, as measured by LCM, at least once per week over 6 months (95% confidence interval [CI] = 1.03-3.13). Subjects taking lamotrigine had an increase of .69 more days per week euthymic as compared with those taking placebo (p = .014).

CONCLUSIONS

Achievement of euthymia across weeks represents a novel paradigm shift in gauging the mood-stabilizing properties of a psychotropic agent. The present findings demonstrate the utility of the prospective Life Chart Method for assessing longitudinal mood stability during randomized clinical trials for bipolar disorder. The results lend support to the potential mood-stabilizing properties of lamotrigine monotherapy for bipolar disorder.

Bipolar (spectrum) disorder and mood stabilization: standing at the crossroads?

Diagnosis and treatment of bipolar disorder has long been a neglected discipline. Recent years have shown an upsurge in bipolar research. When compared to major depressive disorder, bipolar research still remains limited and more expert based than evidence based. In bipolar diagnosis the focus is shifting from classic mania to bipolar depression and hypomania. There is a search for bipolar signatures in symptoms and course of major depressive episodes. The criteria for hypomania are softened, leading to a bipolar prevalence that now equals that of major depressive disorder. Anti-epileptics and atypical antipsychotics have joined lithium in the treatment of bipolar disorder. Fortunately, mood stabilization has become the core issue in bipolar disorder treatment. In contrast with recent trends in the diagnosis of bipolar disorder, treatment research remains more focused on classic mania than depression or hypomania. This leaves the clinician with the difficult task of diagnosing 'new bipolar patients' for whom no definite evidence-based treatment is available. An important efficacy-effectiveness gap further compromises the translation of the evidence base on bipolar disorder treatment into clinical practice. The recent upsurge of research on bipolar disorder is to be applauded, but further research is needed: for bipolar disorder in general, and for bipolar depression and the long-term treatment specifically. Given the complexity of the disorder and the many clinical uncertainties, effectiveness studies should be installed.

The psychopathology and treatment of bipolar disorder

In this chapter we review research on the diagnosis, course, etiology, and pharmacological and psychosocial treatment of bipolar disorder (BD). BD is a highly recurrent and severe illness, with high rates of suicidality and functional impairment. The disorder is heritable and appears to share susceptibility genes with schizophrenia. It is characterized by dysregulation in the dopamine and serotonin systems and by pathology in the brain systems involved in regulating emotion. Psychosocial stressors, notably life events and familial expressed emotion, significantly influence the course of the illness in the context of these vulnerabilities. Findings of randomized clinical trials indicate that psychosocial interventions enhance long-term outcomes when added to pharmacotherapy. Much remains to be clarified about the interactive contributions of genetic, neurobiological, and psychosocial factors to the course of the disorder, and the moderators and mediators of treatment effects.

Mood stabilization in the treatment of bipolar disorder: focus on quetiapine

The use of at least one mood-stabilizing agent is common clinical practice in the treatment of bipolar disorder, regardless of the treatment setting or disease phase. However, a consensus definition of 'mood stabilizer' remains to be established. A mood stabilizer has been operationally described as an agent that is useful in at least one phase of bipolar disorder while not worsening any other phase of the illness. More stringent definitions have been proposed, and it can be argued that a clinically effective mood stabilizer would have efficacy in a broad range of affective, psychotic, behavioral and cognitive domains in all phases of bipolar disorder and would be well tolerated across a range of doses for sustained periods. Clinically effective mood stabilizers should treat mania and depression, while preventing recurrence and improving quality of life. Effective treatment should not precipitate mania, depression, or rapid cycling, and should minimize the burden of treatment-emergent side effects. Data from clinical studies of quetiapine are reviewed in context with the literature discussing traditional and emerging mood stabilizers. Using a liberal definition, the evidence for quetiapine qualifies it as a bimodal mood stabilizer based on its demonstrated effectiveness in the treatment of bipolar mania and depression. Further data suggest that quetiapine has promise across all phases of bipolar disorder with the potential to meet even the most stringent definitions of a mood stabilizer.

Evaluation of the effects of lamotrigine, valproate and carbamazepine in a rodent model of mania

Bipolar disorder is a psychiatric condition characterised by episodes of mania, depression, and underlying mood instability. Anticonvulsant drugs have an established place in the treatment of the disorder, but identifying novel drugs in this class is complicated by the absence of validated animal models. We have evaluated the efficacy of three anticonvulsant mood stabilising drugs (lamotrigine, valproate, and carbamazepine) in a model of mania, in which hyperactivity is induced by the combination of D-amphetamine and chlordiazepoxide. All three drugs were effective at preventing the hyperactivity. Lower doses of valproate and carbamazepine were required to prevent hyperactivity compared to doses required to block tonic-clonic seizures induced by pentylenetetrazole. Lamotrigine was equipotent in the two models. However, the complex pharmacology of the D-amphetamine/chlordiazepoxide model means that there may be several mechanisms by which hyperactivity can be reduced, and these may have more or less relevance to the treatment of bipolar disorder. To address this issue, we also evaluated effects of the three anticonvulsants on baseline locomotion, on activity in the presence of chlordiazepoxide alone, or on activity induced by D-amphetamine alone. Based on the results, we propose that hyperactivity induced by D-amphetamine/chlordiazepoxide may arise through dopaminergic drive coupled with disinhibition caused by low doses of the benzodiazepine. The efficacy of lamotrigine may then arise through a reduction in neuronal excitability or increased glutamate transmission, these latter a consequence of the disinhibition. Carbamazepine may also reduce excitability and glutamate release, but its broader pharmacology, manifested by sedation at higher doses complicates interpretation of its efficacy and reflects its poorer tolerability in the clinic. Valproate may be effective, at least in part, through an enhancement of GABAergic transmission. The predictive validity of the D-amphetamine/chlordiazepoxide model for efficacy in bipolar disorder remains to be established, and research with a wider range of clinically tested drugs is warranted to help validate the model further. In the meantime, the model may be useful for distinguishing novel anticonvulsant drugs with different mechanisms of action.

Gene silencing: a possible molecular mechanism in remission of affective disorder

Based upon a case report, the hypothesis is proposed that a virus infection could be responsible for remission of affective disease by causing gene silencing. A farmer of 59 had been suffering from a therapy resistant depressive episode over many months. His depressive illness seemed primarily biogenetically determined. Because of acute suicidality clinical treatment and observation became necessary. After six weeks of unsuccessful psychiatric treatment the patient caught a severe virus infection causing pneumonia and myocarditis. The physical treatment showed up to be difficult, but finally managed to cope with the virus infection. Remarkably, parallel to the decrease of physical symptoms also the mood was markedly elevated towards a full remission. At that time the patient was no longer under antidepressant medication. Many viruses have a genetic blueprint made from RNA, rather than DNA. When they infect a cell, double-stranded copies (double-stranded RNA, dsRNA) of their genetic material are produced. In response, the RNA interference (RNAi) pathway of the infected cell is activated. The enzyme Dicer first chops viral dsRNA into small segments of 21-25 basepairs in length, termed short interfering RNAs (siRNAs) and these siRNAs are used to identify intact viral RNA and to mark it for destruction. When an endogenous gene is activated, its sequence is read to produce messenger RNA (mRNA), which contains the information necessary to produce a particular protein, and improper expression of an endogenous gene could cause affective disorder in a patient. Therefore one would expect that if such a patient were infected by a virus that contained a sequence similar to the improperly expressed endogenous gene, the patient's anti-viral response would inadvertently reduce expression of the gene causing affective disorder. If mutations in genes responsible for affective disorders are identified and they turn out to cause over-expression of a particular gene, gene silencing could be an alternative therapeutic tool, especially for therapy-resistant severe depression. The therapy could involve introducing dsRNA either as synthetic RNA, or by infecting the patient with a recombinant virus containing sequence from the gene whose expression must be reduced.