Pharmacological treatment of bipolar depression

Predicting treatment effects in unipolar depression: A meta-review

There is increasing interest in clinical prediction models in psychiatry, which focus on developing multivariate algorithms to guide personalized diagnostic or management decisions. The main target of these models is the prediction of treatment response to different antidepressant therapies. This is because the ability to predict response based on patients' personal data may allow clinicians to make improved treatment decisions, and to provide more efficacious or more tolerable medications to the right patient. We searched the literature for systematic reviews about treatment prediction in the context of existing treatment modalities for adult unipolar depression, until July 2019. Treatment effect is defined broadly to include efficacy, safety, tolerability and acceptability outcomes. We first focused on the identification of individual predictor variables that might predict treatment response, and second, we considered multivariate clinical prediction models. Our meta-review included a total of 10 systematic reviews; seven (from 2014 to 2018) focusing on individual predictor variables and three focusing on clinical prediction models. These identified a number of sociodemographic, phenomenological, clinical, neuroimaging, remote monitoring, genetic and serum marker variables as possible predictor variables for treatment response, alongside statistical and machine-learning approaches to clinical prediction model development. Effect sizes for individual predictor variables were generally small and clinical prediction models had generally not been validated in external populations. There is a need for rigorous model validation in large external data-sets to prove the clinical utility of models. We also discuss potential future avenues in the field of personalized psychiatry, particularly the combination of multiple sources of data and the emerging field of artificial intelligence and digital mental health to identify new individual predictor variables.

Bipolar depression: a major unsolved challenge

Depression in bipolar disorder (BD) patients presents major clinical challenges. As the predominant psychopathology even in treated BD, depression is associated not only with excess morbidity, but also mortality from co-occurring general-medical disorders and high suicide risk. In BD, risks for medical disorders including diabetes or metabolic syndrome, and cardiovascular disorders, and associated mortality rates are several-times above those for the general population or with other psychiatric disorders. The SMR for suicide with BD reaches 20-times above general-population rates, and exceeds rates with other major psychiatric disorders. In BD, suicide is strongly associated with mixed (agitated-dysphoric) and depressive phases, time depressed, and hospitalization. Lithium may reduce suicide risk in BD; clozapine and ketamine require further testing. Treatment of bipolar depression is far less well investigated than unipolar depression, particularly for long-term prophylaxis. Short-term efficacy of antidepressants for bipolar depression remains controversial and they risk clinical worsening, especially in mixed states and with rapid-cycling. Evidence of efficacy of lithium and anticonvulsants for bipolar depression is very limited; lamotrigine has long-term benefit, but valproate and carbamazepine are inadequately tested and carry high teratogenic risks. Evidence is emerging of short-term efficacy of several modern antipsychotics (including cariprazine, lurasidone, olanzapine-fluoxetine, and quetiapine) for bipolar depression, including with mixed features, though they risk adverse metabolic and neurological effects.

Pharmacological treatment of adult bipolar disorder

We summarize evidence supporting contemporary pharmacological treatment of phases of BD, including: mania, depression, and long-term recurrences, emphasizing findings from randomized, controlled trials (RCTs). Effective treatment of acute or dysphoric mania is provided by modern antipsychotics, some anticonvulsants (divalproex and carbamazepine), and lithium salts. Treatment of BD-depression remains unsatisfactory but includes some modern antipsychotics (particularly lurasidone, olanzapine + fluoxetine, and quetiapine) and the anticonvulsant lamotrigine; value and safety of antidepressants remain controversial. Long-term prophylactic treatment relies on lithium, off-label use of valproate, and growing use of modern antipsychotics. Lithium has unique evidence of antisuicide effects. Methods of evaluating treatments for BD rely heavily on meta-analysis, which is convenient but with important limitations. Underdeveloped treatment for BD-depression may reflect an assumption that effects of antidepressants are similar in BD as in unipolar major depressive disorder. Effective prophylaxis of BD is limited by the efficacy of available treatments and incomplete adherence owing to adverse effects, costs, and lack of ongoing symptoms. Long-term treatment of BD also is limited by access to, and support of expert, comprehensive clinical programs. Pursuit of improved, rationally designed pharmacological treatments for BD, as for most psychiatric disorders, is fundamentally limited by lack of coherent pathophysiology or etiology.

New approaches to treating resistant depression

Persistent major depression that does not respond to adequate first- or second-line treatment is a common problem in psychiatry. This article updates evidence on recommended treatment strategies and reviews the prospects of more experimental approaches. The main pharmacological development in recent years has been the demonstration that several atypical antipsychotic drugs are effective adjunctive agents in improving symptoms in depression unresponsive to selective serotonin reuptake inhibitors, although their adverse effect burden is high. There is optimism about novel pharmacological strategies based on glutamatergic and anti-inflammatory mechanisms. It is important to combine drug and psychological treatments whenever possible. With persistent therapeutic engagement, the majority of patients remit eventually, but subsequent relapse remains a problem. Clinicians should pursue an active and collaborative treatment plan that makes use of all effective therapeutic modalities and continues into the relapse-prevention phase.

Effects of the potential lithium-mimetic, ebselen, on brain neurochemistry: a magnetic resonance spectroscopy study at 7 tesla

RATIONALE

Lithium is an effective treatment for bipolar disorder, but safety issues complicate its clinical use. The antioxidant drug, ebselen, may be a possible lithium-mimetic based on its ability to inhibit inositol monophosphatase (IMPase), an action which it shares with lithium.

OBJECTIVES

Our primary aim was to determine whether ebselen lowered levels of inositol in the human brain. We also assessed the effect of ebselen on other brain neurometabolites, including glutathione, glutamate, glutamine, and glutamate + glutamine (Glx)

METHODS

Twenty healthy volunteers were tested on two occasions receiving either ebselen (3600 mg over 24 h) or identical placebo in a double-blind, random-order, crossover design. Two hours after the final dose of ebselen/placebo, participants underwent proton magnetic resonance spectroscopy ((1)H MRS) at 7 tesla (T) with voxels placed in the anterior cingulate and occipital cortex. Neurometabolite levels were calculated using an unsuppressed water signal as a reference and corrected for individual cerebrospinal fluid content in the voxel.

RESULTS

Ebselen produced no effect on neurometabolite levels in the occipital cortex. In the anterior cingulate cortex, ebselen lowered concentrations of inositol (p = 0.028, Cohen's d = 0.60) as well as those of glutathione (p = 0.033, d = 0.58), glutamine (p = 0.024, d = 0.62), glutamate (p = 0.01, d = 0.73), and Glx (p = 0.001, d = 1.0).

CONCLUSIONS

The study suggests that ebselen produces a functional inhibition of IMPase in the human brain. The effect of ebselen to lower glutamate is consistent with its reported ability to inhibit the enzyme, glutaminase. Ebselen may have potential as a repurposed treatment for bipolar disorder.

Co-occurrence of anxiety and bipolar disorders: clinical and therapeutic overview

BACKGROUND

Anxiety commonly co-occurs with bipolar disorders (BDs), but the significance of such "co-morbidity" remains to be clarified and its optimal treatment adequately defined.

METHODS

We reviewed epidemiological, clinical, and treatment studies of the co-occurrence of BD and anxiety disorder through electronic searching of Pubmed/MEDLINE and EMBASE databases.

RESULTS

Nearly half of BD patients meet diagnostic criteria for an anxiety disorder at some time, and anxiety is associated with poor treatment responses, substance abuse, and disability. Reported rates of specific anxiety disorders with BD rank: panic ≥ phobias ≥ generalized anxiety ≥ posttraumatic stress ≥ obsessive-compulsive disorders. Their prevalence appears to be greater among women than men, but similar in types I and II BD. Anxiety may be more likely in depressive phases of BD, but relationships of anxiety phenomena to particular phases of BD, and their temporal distributions require clarification. Adequate treatment trials for anxiety syndromes in BD patients remain rare, and the impact on anxiety of treatments aimed at mood stabilization is not clear. Benzodiazepines are sometimes given empirically; antidepressants are employed cautiously to limit risks of mood switching and emotional destabilization; lamotrigine, valproate, and second-generation antipsychotics may be useful and relatively safe.

CONCLUSIONS

Anxiety symptoms and syndromes co-occur commonly in patients with BD, but "co-morbid" phenomena may be part of the BD phenotype rather than separate illnesses.

Options for pharmacological treatment of refractory bipolar depression

Bipolar disorders of types I and II, even when treated by currently standard options, show a marked excess of depressive morbidity. Treated, type I patients in mid-course or from the onset of illness are ill, overall, 50 % of weeks of follow-up, and 75 % of that unresolved morbidity is depressive. Currently widely held impressions are that bipolar depression typically is poorly responsive to antidepressants, that treatment-resistant depression (TRD) is characteristic of the disorder, and that risk of mania with antidepressant treatment is very high. However, none of these views is supported consistently by available research. TRD may be more prevalent in bipolar than unipolar mood disorders. Relatively intense research attention is directed toward characteristics and treatments of TRD in unipolar depression, but studies of bipolar TRD are uncommon. We found only five controlled trials, plus 10 uncontrolled trials, providing data on a total of 13 drug treatments, all of which involved one or two trials, in 87 % as add-ons to complex, uncontrolled regimens. In two controlled trials, ketamine was superior to placebo but it is short-acting and not orally active; pramipexole was weakly superior to placebo in one controlled trial; three other drugs failed to outperform controls. Other pharmacotherapies are inadequately evaluated and nonpharmacological options are virtually untested in bipolar TRD. The available research supports the view that antidepressants may be effective in bipolar depression provided that currently agitated patients are excluded, that risk of mania with antidepressants is only moderately greater than risk of spontaneous mania, and that bipolar TRD is not necessarily resistant to all treatments.