Medication options in the treatment of treatment-resistant depression

Depression as a Neuroendocrine Disorder: Emerging Neuropsychopharmacological Approaches beyond Monoamines

Depression is currently recognized as a crucial problem in everyday clinical practice, in light of ever-increasing rates of prevalence, as well as disability, morbidity, and mortality related to this disorder. Currently available antidepressant drugs are notoriously problematic, with suboptimal remission rates and troubling side-effect profiles. Their mechanisms of action focus on the monoamine hypothesis for depression, which centers on the disruption of serotonergic, noradrenergic, and dopaminergic neurotransmission in the brain. Nevertheless, views on the pathophysiology of depression have evolved notably, and the comprehension of depression as a complex neuroendocrine disorder with important systemic implications has sparked interest in a myriad of novel neuropsychopharmacological approaches. Innovative pharmacological targets beyond monoamines include glutamatergic and GABAergic neurotransmission, brain-derived neurotrophic factor, various endocrine axes, as well as several neurosteroids, neuropeptides, opioids, endocannabinoids and endovanilloids. This review summarizes current knowledge on these pharmacological targets and their potential utility in the clinical management of depression.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of unipolar depressive disorders, part 1: update 2013 on the acute and continuation treatment of unipolar depressive disorders

OBJECTIVES

This 2013 update of the practice guidelines for the biological treatment of unipolar depressive disorders was developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBP). The goal has been to systematically review all available evidence pertaining to the treatment of unipolar depressive disorders, and to produce a series of practice recommendations that are clinically and scientifically meaningful based on the available evidence. The guidelines are intended for use by all physicians seeing and treating patients with these conditions.

METHODS

The 2013 update was conducted by a systematic update literature search and appraisal. All recommendations were approved by the Guidelines Task Force.

RESULTS

This first part of the guidelines (Part 1) covers disease definition, classification, epidemiology, and course of unipolar depressive disorders, as well as the management of the acute and continuation phase treatment. It is primarily concerned with the biological treatment (including antidepressants, other psychopharmacological medications, electroconvulsive therapy, light therapy, adjunctive and novel therapeutic strategies) of adults.

CONCLUSIONS

To date, there is a variety of evidence-based antidepressant treatment options available. Nevertheless there is still a substantial proportion of patients not achieving full remission. In addition, somatic and psychiatric comorbidities and other special circumstances need to be more thoroughly investigated. Therefore, further high-quality informative randomized controlled trials are urgently needed.

Therapeutic options in treatment-resistant depression

The phenomenon of treatment-resistant depression (TRD), described as the occurrence of an inadequate response after an adequate treatment with antidepressant agents (in terms of dose, duration, and adherence), is very common in clinical practice. It has been broadly defined in the context of unipolar major depression, but alternative definitions for bipolar depression have also been suggested. In both cases, there is a remarkable lack of consensus amongst professionals concerning its operative definition. A relatively wide variety of treatment options for unipolar TRD are available, whilst the evidence is very scanty for bipolar TRD. TRD is associated to poor clinical, functional, and social outcomes. Several novel therapeutic options are currently being investigated as promising alternatives, targeting the neurotransmitter system outside of the standard monoamine hypothesis. Augmentation or combination with lithium or atypical antipsychotics appears as a valid option for both conditions, and the same occurs with electroconvulsive therapy. Other non-pharmacological strategies such as deep brain stimulation may be promising alternatives for the future. The use of cognitive behaviour therapy is recommended for unipolar TRD, but there is no evidence supporting its use in bipolar TRD.

Antidepressant monotherapy and combination of antidepressants in the treatment of resistant depression in current clinical practice: A retrospective study

Abstract Objectives. The aim of this study was to compare efficacy of antidepressant monotherapies and combinations of antidepressants in the treatment of resistant patients in current clinical practice. Methods. We reviewed chart documents of resistant depressive inpatients treated at least 4 weeks with a new treatment. Depressive symptoms and clinical status were assessed using Montgomery and Åsberg Depression Rating Scale (MADRS), Beck Depression Inventory-Short Form and Clinical Global Impression at the baseline, week 2 and in the end of treatment. Results. We identified 81 patients (27 with combinations and 51 with monotherapies) that were suitable for analyses. The combination group achieved higher reduction of MADRS score (14.6 vs 10.2 pts., p=0.02) and response rate (≥ 50% reduction of MADRS, 67% vs 39%, p=0.03). Number needed to treat for response was 4. Conclusions. Based on our results, we suggest that combination of antidepressants might be more effective than monotherapy in clinical practice.

Adherence to antidepressant therapy for major depressive patients in a psychiatric hospital in Thailand

BACKGROUND

Poor adherence to antidepressant therapy is an important barrier to the effective management of major depressive disorder. This study aims to quantify the adherence rate to antidepressant treatment and to determine the pattern of prescriptions of depressed patients in a psychiatric institute in Thailand.

METHODS

This retrospective study used electronic pharmacy data of outpatients aged 15 or older, with a new diagnosis of major depression who received at least one prescription of antidepressants between August 2005 and September 2008. The medication possession ratio (MPR) was used to measure adherence over a 6 month period.

RESULTS

1,058 were eligible for study inclusion. The overall adherence (MPR > 80%) in those attending this facility at least twice was 41% but if we assume that all patients who attended only once were non-adherent, adherence may be as low as 23%. Fluoxetine was the most commonly prescribed drug followed by TCAs. A large proportion of cases received more than one drug during one visit or was switched from one drug to another (39%).

CONCLUSIONS

Adherence to antidepressant therapy for treatment of major depression in Thailand is rather low compared to results of adherence from elsewhere.

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.

Low frequency (1-Hz), right prefrontal repetitive transcranial magnetic stimulation (rTMS) compared with venlafaxine ER in the treatment of resistant depression: a double-blind, single-centre, randomized study

BACKGROUND

Previous studies have shown effectiveness of repetitive transcranial magnetic stimulation (rTMS) in the treatment of depression. This double-blind study compared efficacy of l Hz rTMS over the right prefrontal dorsolateral cortex with venlafaxine ER in the treatment of resistant depression.

METHODS

A total of 60 inpatients with depressive disorder (DSM-IV criteria), who previously did not respond to at least one antidepressant treatment, were randomly assigned to 1 Hz rTMS with placebo and venlafaxine ER with sham rTMS for 4 weeks. The primary outcome measure was score change in the Montgomery-Asberg Depression Rating Scale (MADRS). We also used Clinical Global Impression (CGI) and Beck Depressive. Inventory-Short Form (BDI-SF). The response was defined as a >or=50% reduction of MADRS score.

RESULTS

There were no significant differences between treatment groups in MADRS (p=0.38), BDI-SF (p=0.56) and CGI (p=0.17) scores from baseline to endpoint. Response rates for rTMS (33%) and venlafaxine (39%) as well as remission (MADRS score<or=10 points) rates (19% vs. 23%) and drop-out rate did not differ between treatment groups. There were significant reductions of MADRS, CGI and BDI-SF scores in both groups.

LIMITATIONS

Small sample size. No placebo arm was included for ethical reasons, because both treatments have previously been reported to be more effective than placebo. Relatively short duration of antidepressant treatment.

CONCLUSION

The findings of this study suggest that, at least in the acute treatment, the right sided rTMS produces clinically relevant reduction of depressive symptomatology in patients with resistant depression comparable to venlafaxine ER. Larger sample sizes are required to confirm these results.

Current trends in the assessment and somatic treatment of resistant/refractory major depression: an overview

A significant proportion of depressed patients eventually present with treatment-resistant/refractory major depression (TRD), a debilitating condition that imposes significant health, social, and economic burdens. Recently, a growing level of consensus has been reached on the general meaning of TRD, according to which, depression is considered resistant when at least two trials with antidepressants from different pharmacologic classes (adequate in terms of dose, duration, outcome, and compliance) failed to achieve clinical remission. Regarding the management of TRD, a two-step approach is suggested, involving first the evaluation of factors that may contribute to treatment nonresponse (such as comorbid medical and psychiatric conditions), and second, the use of the four classical strategies for enhancing antidepressant efficacy (namely optimization, augmentation, combination, and switching). Finally, future research on TRD should include studies addressing, among other issues, the validity of the proposed definitional criteria, the evaluation of reliable predictors of treatment outcome, and the development of novel therapeutic strategies.

Pharmacogenetics of major depression: insights from level 1 of the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial

Major depression is a serious mental illness frequently associated with devastating consequences for those affected. Suicide rates are significantly elevated, creating a sense of urgency to identify effective yet safe treatment options. A plethora of antidepressants are available on the market today, designed to act on different neurotransmitter systems in the brain, providing the clinician with several treatment strategies. There is, however, very little guidance as to which antidepressant may be most successful in a certain individual. Biomarkers that can predict treatment outcome would thus be of great value, shortening the time until remission and reducing costs for the healthcare system by reducing unsuccessful treatment attempts. The proven contribution of heredity to major depression risk suggests that genetic markers may be good biomarkers for treatment outcome.The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study and a large ancillary pharmacogenetic study in 1953 STAR*D participants constitute the largest effort to date to identify genetic predictors of antidepressant treatment outcome. In this review, the results of candidate gene studies carried out so far are summarized and discussed, and some future directions are proposed.

World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Unipolar Depressive Disorders in Primary Care

These practical guidelines for the biological treatment of unipolar depressive disorders in primary care settings were developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBP). They embody the results of a systematic review of all available clinical and scientific evidence pertaining to the treatment of unipolar depressive disorders and offer practical recommendations for general practitioners encountering patients with these conditions. The guidelines cover disease definition, classification, epidemiology and course of unipolar depressive disorders, and the principles of management in the acute, continuation and maintenance phase. They deal primarily with biological treatment (including antidepressants, other psychopharmacological and hormonal medications, electroconvulsive therapy, light therapy).

Changes in QEEG prefrontal cordance as a predictor of response to antidepressants in patients with treatment resistant depressive disorder: a pilot study

INTRODUCTION

Previous studies of patients with unipolar depression have shown that early decreases of EEG cordance (a new quantitative EEG method) can predict clinical response. We examined whether early QEEG decrease represents a phenomenon associated with response to treatment with different antidepressants in patients with treatment resistant depression.

METHOD

The subjects were 17 inpatients with treatment resistant depression. EEG data and response to treatment were monitored at baseline and after 1 and 4 weeks on an antidepressant treatment. QEEG cordance was computed at three frontal electrodes in theta frequency band. The prefrontal cordance combines complementary information from absolute and relative power of EEG spectra. Recent studies have shown that cordance correlates with cortical perfusion. Depressive symptoms were assessed using Montgomery-Asberg Depression Rating Scale (MADRS).

RESULTS

All 17 patients completed the 4-week study. All five responders showed decreases in prefrontal cordance after the first week of treatment. Only 2 of the 12 nonresponders showed early prefrontal cordance decrease. The decrease of prefrontal QEEG cordance after week 1 in responders as well as the increase in nonresponders were both statistically significant (p-value 0.03 and 0.01, respectively) and the changes of prefrontal cordance values were different between both groups (p-value 0.001).

CONCLUSION

Our results suggest that decrease in prefrontal cordance may indicate early changes of prefrontal activity in responders to antidepressants. QEEG cordance may become a useful tool in the prediction of response to antidepressants.

Peripheral thyroid dysfunction in depression

The involvement of the thyroid gland and thyroid hormones is generally believed to be important in the aetiopathogenesis of major depression. Major support comes from studies in which alterations in components of the hypothalamic-pituitary-thyroid (HPT) axis have been documented in patients with primary depression. However, screening thyroid tests are often routine and add little to the diagnostic evaluation. Overt thyroid disease is rare among depressed inpatients. The finding that depression often co-exists with autoimmune subclinical thyroiditis suggests that depression may cause alterations in the immune system, or that in fact it could be an autoimmune disorder itself. The outcome of treatment and the course of depression may be related to thyroid status as well. Augmentation of antidepressant therapy with the co-administration of thyroid hormones (mainly T3) is a well-documented treatment option for refractory depressed patients. Review of the literature suggests that there are no conclusive data on the role of thyroid function in depression. It is clear that depression is not characterised by an overt thyroid dysfunction, but it is also clear that a subgroup of depressed patients may manifest subtle thyroid abnormalities, or an activation of an autoimmune process. There is a strong possibility that the presence of a subtle thyroid dysfunction is a negative prognostic factor for depression and may demand specific therapeutic intervention.

Daily and spaced treatment with transcranial magnetic stimulation in major depression: a pilot study

OBJECTIVE

Transcranial magnetic stimulation is an emerging treatment of treatment-resistant depression. Current protocols rely on daily treatments. This study was designed to determine whether the time period over which treatment is delivered is an important factor in efficacy.

METHOD

Sixteen adult patients with treatment-resistant major depression were randomly assigned to one of the two treatment groups, both of which received 2 weeks of treatment. One group received daily treatment (10 treatments, on business days). The other group received three treatments in week one, and two treatments in week two (five treatments, on spaced business days). Mood was rated using the Hamilton Depression Rating Scale (HDRS) and a self-rated visual analogue scale. Response was defined as a 50% reduction in HDRS rating, and remission was defined as achieving an HDRS score of 8 or less. The groups were compared throughout the 2-week study period.

RESULTS

At entry, there were no demographic differences between the groups. Multivariate tests showed a significant main effect for time (Pillai trace=0.76, F(4,56)=8.56, p<0.001, power=0.99) reflecting the improvement in both measures of depression during treatment. There was no significant difference between the groups overall (Pillai trace=0.25, F(2,13)=2.12, p=0.16, power=0.36). Additionally, there was no significant interaction between time and treatment group (Pillai trace=0.18, F(4,56)=1.35, p=0.26, power=0.39) indicating that the significant improvement in depression over time was similar for both treatment groups. There were no significant differences in response and remission rates between the groups.

CONCLUSION

The time period of treatment appeared to be an important outcome factor. This suggests that less than daily transcranial magnetic stimulation treatment may be a useful clinical alternative.