Treatment of resistant depression by adding noradrenergic agents to lithium augmentation of SSRIs

Therapeutic options for treatment-resistant depression

Treatment-resistant depression (TRD) presents major challenges for both patients and clinicians. There is no universally accepted definition of TRD, but results from the US National Institute of Mental Health's (NIMH) STAR*D (Sequenced Treatment Alternatives to Relieve Depression) programme indicate that after the failure of two treatment trials, the chances of remission decrease significantly. Several pharmacological and nonpharmacological treatments for TRD may be considered when optimized (adequate dose and duration) therapy has not produced a successful outcome and a patient is classified as resistant to treatment. Nonpharmacological strategies include psychotherapy (often in conjunction with pharmacotherapy), electroconvulsive therapy and vagus nerve stimulation. The US FDA recently approved vagus nerve stimulation as adjunctive therapy (after four prior treatment failures); however, its benefits are seen only after prolonged (up to 1 year) use. Other nonpharmacological options, such as repetitive transcranial stimulation, deep brain stimulation or psychosurgery, remain experimental and are not widely available. Pharmacological treatments of TRD can be grouped in two main categories: 'switching' or 'combining'. In the first, treatment is switched within and between classes of compounds. The benefits of switching include avoidance of polypharmacy, a narrower range of treatment-emergent adverse events and lower costs. An inherent disadvantage of any switching strategy is that partial treatment responses resulting from the initial treatment might be lost by its discontinuation in favour of another medication trial. Monotherapy switches have also been shown to have limited effectiveness in achieving remission. The advantage of combination strategies is the potential to build upon achieved improvements; they are generally recommended if partial response was achieved with the current treatment trial. Various non-antidepressant augmenting agents, such as lithium and thyroid hormones, are well studied, although not commonly used. There is also evidence of efficacy and increasing use of atypical antipsychotics in combination with antidepressants, for example, olanzapine in combination with fluoxetine (OFC) or augmentation with aripiprazole. The disadvantages of a combination strategy include multiple medications, a broader range of treatment-emergent adverse events and higher costs. Several experimental pharmaceutical treatment alternatives for TRD are also being explored in combination with antidepressants or as monotherapy. These less studied alternative compounds include pindolol, inositol, CNS stimulants, hormones, herbal supplements, omega-3 fatty acids, S-adenosyl-L-methionine, folic acid, lamotrigine, modafinil, riluzole and topiramate. In summary, despite an increasing variety of choices for the treatment of TRD, this condition remains universally undefined and represents an area of unmet medical need. There are few known approved pharmacological agents for TRD (aripiprazole and OFC) and overall outcomes remain poor. This might be an indication that depression itself is a heterogeneous condition with a great diversity of pathologies, highlighting the need for careful evaluation of individuals with depressive symptoms who are unresponsive to treatment. Clearly, more research is needed to provide clinicians with better guidance in making those treatment decisions--especially in light of accumulating evidence that the longer patients are unsuccessfully treated, the worse their long-term prognosis tends to be.

An open pilot study of the combination of escitalopram and bupropion-SR for outpatients with major depressive disorder

OBJECTIVE

Monotherapy with a selective serotonin reuptake inhibitor (SSRI) is the most common initial treatment for major depressive disorder (MDD), but this monotherapy leads to remission in fewer than a third of patients. The combination of the SSRI escitalopram and bupropion-SR is commonly used for treating patients with MDD who have had an inadequate response to antidepressant monotherapy. This pilot study was conducted to evaluate this combination in the treatment of MDD in patients with chronic or recurrent MDD to estimate safety, tolerability, and remission rates.

METHOD

In this study, 51 outpatients with chronic or recurrent non-psychotic MDD were treated with a combination of escitalopram and bupropion-SR for up to 12 weeks. Participants were started on escitalopram at 10 mg/day, and bupropion-SR was then added at week 1, starting at 150 mg/day. The maximum dose of escitalopram was 20 mg/day and the maximum dose of bupropion-SR was 400 mg/day.

RESULTS

Rates of response (62%) and remission (50%) at study exit (based on participants for whom at least one post-baseline measure was collected) were significantly higher than is typical for SSRI monotherapy. The level of treatment emergent adverse events was low, and only 3 participants (6%) discontinued treatment due to side effects. The mean maximum dose of escitalopram was 18 mg/day, which was achieved by week 6, and the mean dose at study exit was also 18 mg/day. The mean maximum dose of bupropion-SR was 329 mg/day, which was achieved by week 8, and the mean dose at study exit was 327 mg/day.

CONCLUSIONS

These results suggest that the combination of escitalopram and bupropion-SR is effective and well tolerated. Further controlled trials comparing this combination with monotherapy are needed.

Combined treatments for major depression

Major depression is a chronic disorder with a high morbidity and mortality. Approved treatment for major depression at present includes monotherapy with antidepressants of different pharmacologic classes. There is increasingly widespread use of two other options: augmentation, the addition to an antidepressant of a second compound that is not an antidepressant when used alone; and combination, which is the use of two antidepressants concurrently to enhance or accelerate response. This review focuses on the data available to support these various augmentation and combination treatments.

A Critical Overview of the Pharmacologic Management of Treatment-Resistant Depression

Major depressive disorder is a frequent, serious disorder that usually responds partially to treatment and leaves many patients with treatment resistance. This article reviews and critically evaluates the evidence for the management of treatment-resistant depression and examines pharmacologic approaches to alleviate the suffering of patients who benefit insufficiently from initial treatment.

Current status of augmentation and combination treatments for major depressive disorder: a literature review and a proposal for a novel approach to improve practice

Most patients with major depressive disorder (MDD) do not reach symptom remission. These patients with residual symptoms have worse function and worse prognosis than those who remit. Several augmentation and combination treatments are used to either increase the chances of achieving remission or to eliminate/minimize residual depressive symptoms. Evidence for these pharmacological approaches rests primarily on open, uncontrolled studies, and there are clearly not enough controlled studies. Clinicians should carefully weigh these different treatment options to increase their patients' chances of achieving and sustaining remission from depression. This paper will review the pertinent studies and will propose a novel approach to improve practice involving the use of augmentation or combination strategies at the outset of initial treatment to primarily enhance the chances of remission through synergy and/or a broader spectrum of action. This novel approach could potentially enhance retention and/or increase remission rates since the lack of response with antidepressant monotherapy may lead many depressed patients with little or no benefit to drop out of treatment, precluding the subsequent use of augmentation or combination strategies altogether. In addition, the emergence of certain side-effects (e.g., agitation, insomnia) or the persistence of some initial baseline symptoms (e.g., anxiety, insomnia) may lead to premature discontinuation from monotherapy in the absence of concomitant use of augmenting pharmacological options targeting these symptoms.

Double depression: its morbidity and management in a community setting

BACKGROUND

Double depression, the combination of major depression and dysthymia, is associated with poor health-related quality of life (HRQoL) and increased health service utilization.

OBJECTIVE

To determine the prevalence of double depression, its associated morbidity and use of health services and antidepressants.

METHODS

A random and representative sample of the South Australian general population was interviewed. The mood module of the Primary Care Evaluation of Mental Disorders (PRIME-MD), the Short-Form Health Status Questionnaire (SF-36) and Assessment of Quality of Life (AQoL) instruments were administered, and data relating to health service utilization, antidepressant use and role functioning were collected.

RESULTS

Double depression was present in 3.3% of the population. The use of health services was significantly higher in this group than those with no depression, or dysthymia or major depression alone. Only 15.2% had attended a community health service, 18.2% had seen a psychiatrist, 10.1% a psychologist, 16.2% a social worker and 9.1% any other counsellor in the last month. While 41.4% were currently taking an antidepressant, the average doses of the two most commonly prescribed antidepressants were below the maximum recommended doses, and the use of antidepressant augmentation strategies was also minimal.

CONCLUSIONS

While double depression is associated with increased morbidity and use of health services, the optimum use of both pharmacological and nonpharmacological treatments is clearly lacking in this community sample.

Use of bupropion in combination with serotonin reuptake inhibitors

Incomplete symptom remission and sexual side effects are common problems for which bupropion often is added to treatment with selective serotonin and serotonin-norepinephrine reuptake inhibitors (SSRIs and SNRIs) for patients with major depressive disorder (MDD). This article reviews the literature on combining bupropion with SSRIs or SNRIs. We used MEDLINE to select studies that included patients diagnosed with MDD treated with any combination of bupropion and an SSRI or SNRI, either to enhance antidepressant response or to ameliorate antidepressant-associated sexual dysfunction. Bibliographies of located articles were searched for additional studies. Controlled and open-label studies support the effectiveness of bupropion in reversing antidepressant-associated sexual dysfunction, whereas open trials suggest that combination treatment with bupropion and an SSRI or SNRI is effective for the treatment of MDD in patients refractory to the SSRI, SNRI, or bupropion alone. The available data suggest that, although not an approved indication, the combination of bupropion and either an SSRI or an SNRI is generally well tolerated, can boost antidepressant response, and can reduce SSRI or SNRI-associated sexual side effects. Additional randomized controlled studies are needed to answer important questions, such as those regarding optimal dose and duration of treatment.

Double depression in an Australian population

BACKGROUND

Double depression, or dysthymia with superimposed major depression, is a major public health issue that imposes considerable burden on the community. Double depression and its associated morbidity have not previously been delineated in an Australian population.

METHODS

A random and representative sample of the South Australian population was assessed by trained interviewers. The mood module of the Primary Care Evaluation of Mental Disorders (PRIME-MD), the Short-Form Health Status Questionnaire (SF-36), and Assessment of Quality of Life (AQoL) instruments were administered, and data related to treatment use and role functioning were collated.

RESULTS

Double depression was present in 2.2% of the population. This group reported high levels of treatment-seeking behaviour with 90% seeking treatment in the last month and 42.4 % taking antidepressants. They also had a highly significantly poorer quality of life than did others in the community.

CONCLUSIONS

The 2.2% of the population with double depression reported high use of services with poor functioning and health-related quality of life. More effective intervention strategies are required.

A Review of the Neuropharmacology of Bupropion, a Dual Norepinephrine and Dopamine Reuptake Inhibitor

BACKGROUND: The neurochemical and biological effects of antidepressant medications have become better defined over the last decade. When the anti-depressant bupropion was introduced in the United States in 1989, the specific pharmacologic basis of its clinical effects was uncertain. Research conducted over the past decade has significantly advanced the understanding of the neuropharmacology of bupropion and has demonstrated a novel mechanism of antidepressant activity. This article discusses the mechanism of action of bupropion and relates the drug's neuropharmacologic effects to its clinical efficacy and tolerability profiles. DATA SOURCES: Data were obtained via the MEDLINE database in an English-language search spanning the period 1965 to May 2002 and using the search terms bupropion, bupropion SR, and antidepressants, as well as from the manufacturer's bupropion databases. CONCLUSIONS: The preclinical and clinical data show that bupropion acts via dual inhibition of norepinephrine and dopamine reuptake and is devoid of clinically significant serotonergic effects or direct effects on postsynaptic receptors. Dual norepinephrine and dopamine reuptake inhibition is associated with a unique clinical profile. Bupropion has demonstrated efficacy comparable to that of other antidepressants. However, because bupropion is a selective norepinephrine and dopamine reuptake inhibitor with no serotonergic activity, common antidepressant-associated side effects, such as sexual dysfunction, weight gain, and sedation, are not associated with bupropion therapy.