Cecylia Nowakowska

Psychotic bipolar disorders: dimensionally similar to or categorically different from schizophrenia?

For over a century, clinicians have struggled with how to conceptualize the primary psychoses, which include psychotic mood disorders and schizophrenia. Indeed, the nature of the relationship between mood disorders and schizophrenia is an area of ongoing controversy. Psychotic bipolar disorders have characteristics such as phenomenology, biology, therapeutic response, and brain imaging findings, suggesting both commonalities with and dissociations from schizophrenia. Taken together, these characteristics are in some instances most consistent with a dimensional view, with psychotic bipolar disorders being intermediate between non-psychotic bipolar disorders and schizophrenia spectrum disorders. However, in other instances, a categorical approach appears useful. Although more research is clearly necessary to address the dimensional versus categorical controversy, it is feasible that at least in the interim, a mixed dimensional/categorical approach could provide additional insights into pathophysiology and management options, which would not be available utilizing only one of these models.

The Diverse Roles of Anticonvulsants in Bipolar Disorders

Anticonvulsant drugs (ACs) have diverse antiseizure, psychotropic, and biochemical effects. Carbamazepine and valproate have mood-stabilizing actions, benzodiazepines and gabapentin have anxiolytic actions, lamotrigine is useful in rapid cycling and acute treatment and prophylaxis of bipolar depression, and topiramate and zonisamide can yield weight loss. Limited controlled data suggest the carbamazepine keto derivative oxcarbazepine has antimanic effects. A categorical approach to the diverse roles of ACs in bipolar disorders is proposed, using broad categories of ACs, on the basis of their predominant psychotropic profiles. Thus, some ACs have “sedating” profiles that may include sedation, cognitive difficulties, fatigue, weight gain, and possibly antimanic and/or anxiolytic effects. In contrast, some newer ACs have “activating” profiles that may include improved energy, weight loss, and possibly antidepressant and even anxiogenic effects. Still other newer ACs have novel “mixed” profiles, combining sedation and weight loss. A categorical–mechanistic extension of this approach is also presented, with hypotheses that “sedating” profiles might be related to prominent potentiation of gamma-aminobutyric acid (GABA) inhibitory neurotransmission, “activating” profiles could be related to prominent attenuation of glutamate excitatory neurotransmission, and for “mixed” profiles, sedation and weight loss might be related to concurrent GABAergic and antiglutamatergic actions, respectively. The categorical approach may have utility as an aid to clinicians in reinforcing the heterogeneity ACs, and recalling psychotropic profiles of individual ACs, but is limited as it fails to address the etiology of the heterogeneity of AC psychotropic effects. The categorical–mechanistic extension strives to address this issue, but requires systematic clinical investigation of more precise relationships between psychotropic profiles and discrete mechanisms of action to assess its merits.

New medication treatment options for bipolar disorders

Objective:  To assess new treatment options for bipolar disorders.

New anticonvulsant medication uses in bipolar disorder.

Therapy of bipolar disorders is a rapidly evolving field. Lithium has efficacy in classic bipolar disorders whereas divalproex sodium and carbamazepine may have broader spectrum efficacy that includes non-classic bipolar disorder. In the last 10 years, a series of anticonvulsants have been approved for marketing in the United States. Gabapentin has indirect g-aminobuytric acid-ergic actions, is generally well tolerated, and appears to have anxiolytic, analgesic, and hypnotic effects. Lamotrigine has antiglutamatergic actions and is generally well tolerated (aside from rash in 1 in 10, and serious rash in 1 in 1,000 patients). Lamotrigine is indicated for maintenance treatment in bipolar disorder. Emerging evidence suggests lamotrigine may have utility in bipolar disorder patients with depression and treatment-refractory rapid cycling, as well as analgesic effects. Topiramate and zonisamide may allow both weight loss, while topiramate may have specific efficacy in bulimia, binge eating disorder, and alcohol dependence. Two small studies found oxcarbazepine had similar efficacy to lithium and haloperidol in acute mania. Phenytoin, an older anticonvulsant, may have adjunctive acute mania efficacy. Levetiracetam, a newer anticonvulsant, may be worth exploring and has minimal drug-drug interactions. None of these newer agents has been shown effective in a large placebo controlled trial for acute mania. Although the clinical profiles of these newer anticonvulsants do not appear to overlap markedly with divalproex and carbamazepine (except perhaps for oxcarbazepine), these novel agents may still offer important new options in relieving a variety of specific target symptoms in patients with bipolar disorder.

Divalproex extended-release in acute bipolar II depression

BACKGROUND Divalproex extended-release (divalproex-ER) is effective in acute mania, and limited data suggest divalproex may have efficacy in acute bipolar depression. METHODS A 7-week, open-label trial of divalproex-ER monotherapy or adjunctive therapy was conducted in 28 outpatients (15 female, mean age 36.7+/-9.1, and mean duration of illness 22.1+/-11.1 years) with bipolar II depression (39% with rapid cycling course of illness within the prior year). Divalproex-ER was generally given as a single dose at bedtime, starting at 250mg and increased by 250mg every 4 days to symptom relief or adverse effects. Efficacy was assessed using weekly prospective Montgomery Asberg Depression Rating Scale (MADRS) scores. RESULTS Overall, mean divalproex-ER final doses and serum concentrations were 1469mg/day and 80.1microg/mL, respectively. Mean MADRS scores (last observation carried forward) decreased significantly from baseline in patients in the overall group (from 30.1 to 15.2, p<.00001). The overall response rate was 54%. Divalproex-ER therapy was generally well tolerated, with no early discontinuations due to adverse events. LIMITATIONS This study is limited by a small sample size and an open-label study design with no placebo control. CONCLUSIONS Divalproex-ER as monotherapy and adjunctive therapy was well tolerated and yielded an overall response rate of 54% in bipolar II depression. Based on the results of this pilot study, randomized, double-blind, placebo-controlled studies of divalproex-ER in bipolar II depression are warranted.