Treatment resistant depression: methodological overview and operational criteria

Comparison of escitalopram and citalopram in outpatients with severe major depressive disorder: a prospective, naturalistic, 8-week study

Objective. Escitalopram is a new selective serotonin reuptake inhibitor indicated for the treatment of major depressive disorder (MDD). The objective of this study is to examine its efficacy in the treatment of severe MDD compared with that of citalopram in daily practice. Method. A prospective, naturalistic, 8-week study was conducted involving 127 patients fulfilling DSM-IV criteria for severe MDD and having a baseline Montgomery-Åsberg Depression Rating Scale (MADRS) score of at least 30. A full non-parsimonious logistic model, called the propensity score, was first defined to reduce bias associated with non-randomization. The primary efficacy analysis was the mean change from baseline to week 8 in MADRS score between the escitalopram and citalopram groups, after stratification on the propensity score. Other efficacy measurements consisted of the Clinical Global Impression of Severity and Improvement scales (CGI-S and CGI-I, respectively), response (defined as a reduction of at least 50% on MADRS from baseline to week 8) and remission rates (defined as MADRS ≤ 12 at week 8), after adjustment on propensity score for escitalopram use. Results. A total of 67 escitalopram-treated patients and 60 citalopram-treated patients were enrolled in this study. Escitalopram reduced mean MADRS total score at week 8 compared with citalopram (-23.5 vs. -17.5; P<0.001). The effect of escitalopram was consistently greater than that of citalopram on the CGI scales. Escitalopram-treated patients were also more likely to respond to treatment (79.4 vs. 44.0%; P<0.001), and remission rates were also in favour of escitalopram (56.9 vs. 11.2%, P<0.001). Analysis of safety data showed better tolerability of escitalopram than that of citalopram. Conclusion. Using adequate methodology to reduce biases due to non-randomization, this study indicates better efficacy and tolerability of escitalopram versus citalopram in severe MDD outpatients.

To combine or not to combine? A literature review of antidepressant combination therapy

OBJECTIVE

Treatment resistant depression is a common clinical problem and a major public health concern. The use of antidepressant combinations to overcome treatment resistance, while somewhat controversial, is a popular strategy in practice. This paper reviews published trials on combination antidepressants with a view to inform clinical practice.

METHOD

A systematic but selective review of the published literature was conducted using EMBASE, PSYCHLIT and MEDLINE with relevant search terms.

RESULTS

A number of trials suggesting efficacy of combination antidepressants were found. These are incorporated into a number of treatment guidelines for the management of treatment refractory depression. Clinicians should be cautious regarding pharmacokinetic and pharmacodynamic interactions, including the serotonin syndrome, however combination strategies are an effective option.

CONCLUSIONS

Many antidepressants can be usefully combined especially if they engage separate mechanisms of action. Clinically, antidepressant combinations provide a useful resort in otherwise treatment resistant individuals. However, much further research is needed to determine relative efficacy and determine long term outcome.

The pharmacological management of depression

Depressive disorders are common, recurrent, and chronic, and require treatment A review of the symptom picture and current drug targets demonstrates the need for accument of depression severity, including suicidaliltial focus of treatment is rapid resolution of: during an acute phase, followed by continuation. Maintenance treatment is indicated if the risk of recurrence is high. The range of available medications is considerable and the benefit/risk ratio is acceptable. Depression is diagnosable across the life span and treatable at every age (although recent disagreement has arisen with regard to young patients). Comorbidity, both psychiatric and medical, need to be assessed, as does the possible presence of two subtypes of depression (psychotic and bipolar) often requiring different interventions. It is expected that the next generation of antidepressants would be associated with more specific disease and outcome biomarkers.

Treatment-resistant depression: resistant to definition?

OBJECTIVE

To better define treatment-resistant depression (TRD) so as to assist clinical management and refine treatment guidelines.

METHOD

In this study, we examine a broad range of clinical variables in depressed patients (n=196) referred to a tertiary referral Mood Disorders Unit (MDU). Information was collected from patients, referrers and assessors over a period of 32 months and included evaluations of treatments, treatment resistance and related variables. Data were analysed across trichotomized 'high', 'low' and 'no' treatment resistance groupings of patients.

RESULTS

A significantly greater proportion of patients with melancholia were amongst the high TRD group, and this was consistent across different strategies for evaluating melancholia.

CONCLUSION

Melancholia perhaps provides a prototypic TRD subset that perhaps reflects some innate aspects of melancholic depression or factors such as the impact of ageing. Research into TRD is needed to both replicate this finding and perhaps explicate it further.

Empirical testing of two models for staging antidepressant treatment resistance

BACKGROUND

An increasing amount of attention has been paid to treatment resistant depression. Although it is quite common to observe nonremission to not just one but consecutive antidepressant treatments during a major depressive episode, a relationship between the likelihood of achieving remission and one's degree of resistance is not clearly known at this time. This study was undertaken to empirically test 2 recent models for staging treatment resistance.

MATERIALS AND METHODS

Psychiatrists from 2 academic sites reviewed charts of patients on their caseloads. Clinical Global Impressions-Severity (CGI-S) and Clinical Global Impressions-Improvement (CGI-I) scales were used to measure severity of depression and response to treatment, and 2 treatment-resistant staging scores were classified for each patient using the Massachusetts General Hospital staging method (MGH-S) and the Thase and Rush staging method (TR-S).

RESULTS

Out of the 115 patient records reviewed, 58 (49.6%) patients remitted at some point during treatment. There was a significant positive correlation between the 2 staging scores, and logistic regression results indicated that greater MGH-S scores, but not TR-S scores, predicted nonremission.

CONCLUSIONS

This study suggests that the hierarchical manner in which the field has typically gauged levels of treatment resistance may not be strongly supported by empirical evidence. This study suggests that the MGH staging model may offer some advantages over the staging method by Thase and Rush, as it generates a continuous score that considers both number of trials and intensity/optimization of each trial.

The level of recognition of physical symptoms in patients with a major depression episode in the outpatient psychiatric practice in Puerto Rico: an observational study

BACKGROUND

This study was designed to evaluate the psychiatrists' level of recognition of somatic symptoms associated to a major depressive episode (MDE) (DSM-IV-TR criteria) and the impact of those somatic symptoms on the treatment effectiveness.

METHODS

This non-interventional study was conducted in 25 medical offices in Puerto Rico from February to December 2003. It had 2 visits separated by 8 weeks. The level of recognition was determined by: the correlation between the physician clinical evaluation and their patients' self-evaluations through different validated instruments using kappa statistics. Chi-square test was used to evaluate the impact of somatic symptoms on treatment antidepressants' effectiveness.

RESULTS

All the 145 recruited patients reported the presence of at least one somatic symptom associated with their current MDE. In the two visits covered by the study, a fair agreement between the psychiatrists' and the patients' reports was noted for headache, abdominal pain and upper limb pains (0.4003 <or= kappa >or= 0.6594). For other painful symptoms and painless somatic symptoms, the Kappa values obtained were non-significant. Slight but significant reductions in depression and painful symptoms severity were observed after 8 weeks of treatment. A proportional relationship between the pain and depression severity was observed (p < 0.0001).

CONCLUSION

The study results show that somatic symptoms: are very common in depressed Puerto Rican patients; are significant under-reported by psychiatrists; and have a significant impact on the antidepressant effectiveness.

The effectiveness of psychological treatments for treatment-resistant depression: a systematic review

OBJECTIVE

A systematic review of all studies (controlled and uncontrolled) to evaluate psychological interventions with treatment-resistant depression.

METHOD

A systematic search to identify studies evaluating a psychological intervention with adults with a diagnosis of major depressive disorder who had not responded to at least one course of antidepressant medication.

RESULTS

Twelve studies met inclusion criteria, of which four were controlled and eight uncontrolled. Treatment effect sizes were computable for four studies and ranged from 1.23 to 3.10 with a number of better quality studies demonstrating some improvements in patients following a psychological intervention.

CONCLUSION

Psychological treatments for depression are commonly delivered and often recommended following the failure of medication. The paucity of evidence for their effectiveness in these situations is a significant problem. There is a need for studies with a strong controlled design investigating the effectiveness of psychological treatments for patients with treatment-resistant depression.

Sustained remission with lamotrigine augmentation or monotherapy in female resistant depressives with mixed cyclothymic-dysthymic temperament

BACKGROUND

The treatment of bipolar depression remains problematic. Lamotrigine has been shown in randomized controlled studies to be efficacious in preventing bipolar depression and rapid cycling states.

METHODS

Twenty-four women with cyclothymic temperament and refractory depression were recruited from four outpatient sites (three primary care and one psychiatric) and treated with lamotrigine in a naturalistic, open-label study. Temperament was determined by responses on the TEMP-A self-rating scale. Eighteen (75%) of these cyclothymic patients also scored high on the depressive temperament. Eighteen (75%) met DSM-IV criteria for bipolar II disorder. In two thirds of the cases, lamotrigine was add-on therapy to an antidepressant. Response to therapy was assessed using the DSM-IV Global Assessment of Functioning (GAF).

LIMITATIONS

This study was naturalistic in design, without controls or blinds.

RESULTS

Of the 23 patients who remained in the study, 16 (70%) had significant, sustained responses. Of these 16, 12 (75% of responders, 52% of the total) had remissions (GAF > 80) sustained longer than 12 months. Robust, sustained responses to lamotrigine monotherapy were seen in 4 patients (17%). Seven patients (30%) received no apparent benefit from lamotrigine.

CONCLUSIONS

Lamotrigine induced prolonged illness remissions in a substantial number of female patients whose symptoms were both complex and refractory. Most manifested high scores on the cyclothymic and depressive temperaments, and prior refractoriness to multiple antidepressant and antidepressant/mood stabilizer combinations, before remitting with lamotrigine augmentation or monotherapy.

Therapy of treatment resistant depression: focus on the management of TRD with atypical antipsychotics

Treatment-resistant depression (TRD) represents a significant challenge for physicians. About one third of patients with major depressive disorder fail to experience sufficient symptom improvement despite adequate treatment. Despite this high occurrence of TRD there was no general consensus on diagnosis criteria for TRD until 1997 when researchers proposed a model of defining and staging TRD. In 1999, others defined operational criteria for the definition of TRD. Treatment of TRD is commonly separated into pharmacologic and nonpharmacologic methods. This review gives a short overview of these two methods. The nonpharmacologic methods include psychotherapy, electroconvulsive therapy, and vagus nerve stimulation. Pharmacologic methods include switching to another antidepressant monotherapy, and augmentation or combination with two or more antidepressants or other agents. This review especially focuses on the augmentation of the antidepressant therapy with atypical antipsychotics.

Characteristics, treatment patterns, and outcomes of persistent depression despite treatment in primary care

We examine the sociodemographic and clinical characteristics of depressed primary care patients who receive at least minimal standards of evidence-based treatment, comparing those who remain depressed with those who recover; and their subsequent treatment patterns and other outcomes. We used observational data from a subset of 542 treated patients participating in a group-level randomized controlled trial of quality improvement interventions for depression conducted in six managed care organizations. Nonresponse to treatment was defined as having at least minimally appropriate treatment for at least two of three 6-month periods but continuing to have probable depression. Our definitions of depression and appropriate treatment are broader than those used in clinical trials, but relevant to primary care settings. Many of the factors predictive of treatment resistance in clinical trials predict nonresponse to guideline concordant care among diverse primary care, depressed patients. The main unique predictors of nonresponse to treatment include a clinical factor (suicide ideation) requiring clinician assessment and intervention, a social/economic factor (unemployment) usually not addressed by medical interventions, and medication nonadherence. Nonresponders used more adjunctive therapies and combination medications, suggesting clinicians and patients were searching for solutions. High rates of service use and poor outcomes emphasize the urgency of new research to find solutions for these patients.

Economic implications of treatment-resistant depression among employees

BACKGROUND

Conservative estimates indicate between 10% and 20% of all individuals with major depressive disorders (MDDs) fail to respond to conventional antidepressant therapies. Amongst those with MDD, individuals with treatment-resistant depression (TRD) have been found to be frequent users of healthcare services and to incur significantly greater costs than those without TRD. Given the prevalence of the disorder, it is understandable that MDDs are responsible for a significant amount of both direct and indirect healthcare costs.

OBJECTIVE

To provide empirical findings for employees likely to have TRD based on analysis of employer claims data, in the context of previous research.

METHODS

We conducted a claims data analysis of employees of a large national (US) employer. The data source consisted of medical, pharmaceutical and disability claims from a Fortune 100 manufacturer for the years 1996-1998 (total beneficiaries >100000). The employee sample included individuals with medical or disability claims for MDDs (n = 1692). A treatment pattern algorithm was applied to classify MDD patients into TRD-likely (n = 180) and TRD-unlikely groups. Treated prevalence of select comorbid conditions and the patient costs (direct and indirect) from the employer perspective by condition were compared among TRD-likely and TRD-unlikely employees, and with a 10% random sample of the overall employee population for 1998.

RESULTS

The average annual cost of employees considered TRD-likely was dollars US 14490 per employee, while the cost for depressed but TRD-unlikely employees was dollars US 6665 per employee, and dollars US 4043 for the employee from the random sample. TRD beneficiaries used more than twice as many medical services compared with TRD-unlikely patients, and incurred significantly greater work loss costs.

CONCLUSION

TRD has gained increasing recognition due to both the clinical challenges and economic burdens associated with the condition. TRD imposes a significant economic burden on an employer. TRD-likely employees are more likely to be treated for selected comorbid conditions and have higher medical and work loss costs across all conditions.

Reducing the burden of affective disorders: is evidence-based health care affordable?

BACKGROUND

Affective disorders remain the leading cause of disability burden despite the availability of efficacious treatment. A wider dissemination of evidence-based health care is likely to impact this burden, however the affordability of such a strategy at the population level is unknown. This study calculated the cost-effectiveness of evidence-based health care for depression, dysthymia and bipolar disorder in the Australian population, and determined whether it was affordable, based on current mental health-related expenditure and outcomes for these disorders.

METHODS

Cost-effectiveness was expressed in costs per years lived with disability (YLDs) averted, a population health summary measure of disability burden. Data from the Australian National Survey of Mental Health and Wellbeing, in conjunction with published randomized trials and direct cost estimates, were used to estimate the 1-year costs and YLDs averted by current health care services, and costs and outcomes for an optimal strategy of evidence-based health care.

RESULTS

Current direct mental health-related health care costs for affective disorders in Australia were 615 million dollars (1997-98 Australian dollars). This treatment averted just under 30,000 YLDs giving a cost-effectiveness ratio of 20,633 dollars per YLD. Outcome could be increased by nearly 50% at similar cost with implementation of an evidence-based package of optimal treatment, halving the cost-effectiveness ratio to 10,737 dollars per YLD.

LIMITATIONS

The method to estimate YLDs averted from the literature requires replication. The costs of implementing evidence-based health care have not been estimated.

CONCLUSIONS

Evidence-based health care for affective disorders should be encouraged on both efficacy and efficiency grounds.

Diagnosis and definition of treatment-resistant depression

Treatment-resistant depression (TRD) typically refers to inadequate response to at least one antidepressant trial of adequate doses and duration. TRD is a relatively common occurrence in clinical practice, with up to 50% to 60% of the patients not achieving adequate response following antidepressant treatment. A diagnostic re-evaluation is essential to the proper management of these patients. In particular, the potential role of several contributing factors, such as medical and psychiatric comorbidity, needs to be taken into account. An accurate and systematic assessment of TRD is a challenge to both clinicians and researchers, with the use of clinician-rated or self-rated instruments being perhaps quite helpful. It is apparent that there may be varying degrees of treatment resistance. Some staging methods to assess levels of treatment resistance in depression are being developed, but need to be tested empirically.

Is treatment-resistant depression a unique subtype of depression?

Treatment-resistant depression (TRD) continues to represent a major challenge for treating clinicians. This report reviews the relevant literature to evaluate whether TRD can be considered a specific subtype of depression based on 1) clinical characteristics and course (behavioral phenotype), 2) neurobiological profile, and 3) context and environment in which TRD develops. Although patients with TRD share a number of clinical, neurobiological, and context and environment characteristics, the lack of available data and the clinical heterogeneity of this condition do not currently permit the classification of TRD as a unique subtype of depression; however, this topic is worthy of further evaluation and research. Performing genetics and neuroimaging studies on patients enrolled in large, prospective and controlled studies may provide enough data for classifying TRD (or at least a part of what is currently described as TRD) as a specific subtype of depression. This in turn may facilitate the identification of more effective treatment strategies.

Treatment-resistant depression in late life

Treatment resistance is reported in up to 40% of older patients with major depression. Before labeling an episode of depression as treatment resistant, it is important to ensure that the diagnosis is correct and that the patient has received and adhered to an adequate dose of treatment for an appropriate length of time. It is also important to assess the patient for comorbid physical and psychiatric conditions that can contribute to treatment resistance. In patients who do not experience remission of symptoms with an adequate trial of medication, the following options can be considered: augmenting the antidepressant with a drug that is not primarily an antidepressant, adding a second antidepressant to the first, switching to a different antidepressant medication, or switching to electroconvulsive therapy. This paper reviews the concept of treatment-resistant depression and discusses its assessment and management in the elderly. The author concludes that when a systematic stepped-care approach to treatment is followed, most older patients with major depression will experience remission of symptoms.

Synergistic effect of uncompetitive NMDA receptor antagonists and antidepressant drugs in the forced swimming test in rats

In spite of intensive research, the problem of treating antidepressant-resistant depressive patients has not yet been solved. The authors previously reported that combined administration of imipramine and the uncompetitive NMDA receptor antagonist amantadine reduced immobility time in the forced swimming test in rats to a much greater extent than either treatment alone. The present paper investigates the possibility of synergistic interactions between three antidepressants (imipramine, venlafaxine, fluoxetine) with three uncompetitive NMDA receptor antagonists (amantadine, memantine and neramexane). Most combinations resulted in synergistic (hyperadditive) antidepressive-like effects in the forced swim test. Most interesting was the observation that fluoxetine, which was inactive when given alone, showed a positive effect when combined with amantadine (10 and 20 mg/kg), memantine (2.5 and 5 mg/kg) or neramexane (2.5 and 5 mg/kg). The specificity of these observations is supported by control open field studies, which demonstrated no significant increase, or even a decrease in general locomotion after coadministration of the compounds. The present results suggest that the combination of traditional antidepressant drugs and NMDA receptor antagonists may produce enhanced antidepressive effects, and this is of particular relevance for antidepressant-resistant patients.

Interaction of psychotropic drugs with monoamine oxidase in rat brain

Literature observations indicate that some psychotropic drugs may have inhibitory activity towards monoamine oxidase (MAO). This study was undertaken to assess the potency, isozyme selectivity and mechanism of inhibition of representative first- and second-generation antidepressant drugs towards rat brain MAO-A and MAO-B. Five tricyclic antidepressants (imipramine, trimipramine, clomipramine, amitriptyline and doxepine) and three selective serotonin reuptake inhibitors (fluoxetine, fluvoxamine and citalopram) were examined. They showed inhibitory activity towards MAO-A and MAO-B, with clear selectivity for MAO-B (Ki in the micromolar range). Their mechanism of inhibition was competitive towards MAO-B and of a mixed competitive type towards MAO-A. The results suggest that some of the drugs examined might also contribute an MAO inhibitory effect in chronically treated patients.

Extrapyramidal symptoms and antidepressant drugs: neuropharmacological aspects of a frequent interaction in the elderly

Depression is the most prevalent functional psychiatric disorder in late life. The problem of motor disorders associated with antidepressant use is relevant in the elderly. Elderly people are physically more frail and more likely to be suffering from physical illness, and any drug given may exacerbate pre-existing diseases, or interact with other drug treatments being administered for physical conditions. Antidepressants have been reported to induce extrapyramidal symptoms, including parkinsonism. These observations prompted us to review the neurobiological mechanism that may be involved in this complex interplay including neurotransmitters and neuronal circuits involved in movement and emotion control and their changes related to aging and disease. The study of the correlations between motor and mood disorders and their putative biochemical bases, as presented in this review, provide a rationale either to understand or to foresee motor side effects for psychotropic drugs, in particular antidepressants.