Therapeutic options in treatment-resistant depression

Longitudinal course of symptom severity and fluctuation in patients with treatment-resistant unipolar and bipolar depression

Little is currently known about the long-term course of symptom severity and fluctuation in patients with treatment-resistant depression (TRD). We assessed this using the longitudinal interval follow-up evaluation in 115 patients with TRD (84 unipolar, 31 bipolar) with 1-7 years (median 36 months) of follow-up. Of the follow-up months, 39.2% were spent asymptomatic and 21.1% at sub-threshold symptom level, while 15.8% were spent at mild, 13.9% at moderate, and 10.0% at severe depressive episode level. Significantly more unipolar than bipolar patients were continuously symptomatic during follow-up (43% vs. 29%). Patients had a mean of 1.0 (S.D.=1.2) symptom severity level fluctuations per year. High fluctuating patients had significantly poorer global functioning and quality of life. Although most patients with TRD achieve an asymptomatic state, they continue to fluctuate and experience depressive symptoms in the majority of months, mostly at subclinical or mild severity. However, there are important differences between unipolar and bipolar TRD, with unipolar patients more likely to experience an unremitting depressive state. Additionally, a more fluctuating longitudinal illness course is associated with poorer function and quality of life, and with a bipolar diagnosis. We suggest that the longitudinal illness course is an important outcome to be considered in future TRD research.

Evidence-based treatment strategies for treatment-resistant bipolar depression: a systematic review

OBJECTIVES

Treatment resistance in bipolar depression is a common clinical problem that constitutes a major challenge for the treating clinician as there is a paucity of treatment options. The objective of this paper was to review the evidence for treatment options in treatment-resistant bipolar depression, as found in randomized controlled trials and with special attention to the definition and assessment of treatment resistance.

METHODS

A Medline search (from database inception to May 2012) was performed using the search terms treatment resistance or treatment refractory, and bipolar depression or bipolar disorder, supplemented with 43 separate searches using the various pharmacologic agents or technical interventions as search terms.

RESULTS

Only seven studies met our inclusion criteria. These studies examined the effects of ketamine (n = 1), (ar)modafinil (n = 2), pramipexole (n = 1), lamotrigine (n = 1), inositol (n = 1), risperidone (n = 1), and electroconvulsive therapy (ECT) (n = 2).

CONCLUSIONS

The available level I evidence for treatment strategies in resistant bipolar depression is extremely scarce, and although the response rates reported are reassuring, most of the strategies remain experimental. There is an urgent need for further study in homogeneous patient samples using a clear concept of treatment resistance.

Electrical stimulation of left anterior thalamic nucleus with high-frequency and low-intensity currents reduces the rate of pilocarpine-induced epilepsy in rats

PURPOSE

Bilateral electrical stimulation of anterior nuclei of thalamus (ANT) has shown promising effects on epileptic seizures. However, bilateral implantation increases the risk of surgical complications and side effects. This study was undertaken to access the effectiveness of a stimulation paradigm involving high frequency and low intensity currents to stimulate the left ANT in rats.

METHODS

Male Sprague-Dawley rats were implanted with electroencephalogram (EEG) electrodes, and an additional concentric bipolar stimulation electrode into either the left or right ANT. The stimulus was a train of pulses (90 μs duration each) delivered with a frequency of 200 Hz and a current intensity of 50 μA. Thalamic stimuli were started 1 h before the first intraperitoneal pilocarpine injection (i.p., 300 mg/kg), and were applied for 5 h.

RESULTS

EEG documented seizure activity and status epilepticus (SE) developed in 87.5% of rats treated with no ANT stimulation after a single dose of pilocarpine. Left ANT stimulation significantly increased the tolerance threshold for pilocarpine-induced EEG seizure activity; 20% of rats developed their EEG documented seizure activity after receiving the first dose, whereas 50%, 10% and 20% of rats did not develop seizure activity until they had received the 2nd, 3rd and 4th pilocarpine injection at 1-h intervals. Moreover, left thalamic stimulation reduced the occurrences of both EEG documented seizure activity and SE induced by single-dose pilocarpine to 25%. However, our result demonstrated that little effect on the occurrence rate of seizures and SE was found when rats received right ANT stimulation.

CONCLUSIONS

These results suggest that continuously 5-h left ANT stimulation with high frequency and low intensity currents, beginning from 1h before the pilocarpine administration, may successfully reduce the occurrence rate of EEG documented seizure activity and SE development in rats.

Depressive disorders and suicide: Epidemiology, risk factors, and burden

The social and economic impact of mood disorders and suicide is extremely high and may be even higher in coming years, and yet, research in mental health is largely underfunded. This report summarizes the most recent data concerning the epidemiology and burden of depression and suicide, and underlines the most recent initiatives to identify the barriers to effective treatment and prevention of mood disorders. Global cooperation and networks of research networks are proposed. Progress in the understanding of the pathophysiology and subtypes of depression, technological advances, emphasis on early prediction of response and prevention, and a paradigm shift in drug development are crucial to overcome the current challenges posed by increasing rates of depression and suicide.

The role of BDNF, NTRK2 gene and their interaction in development of treatment-resistant depression: data from multicenter, prospective, longitudinal clinic practice

BACKGROUND

Although genetic variants may play a key role in development of treatment-resistant depression (TRD), relevant research is scarce.

METHODS

To examine whether the polymorphisms of BDNF (rs6265) and NTRK2 (rs1387923, rs2769605 and rs1565445) genes confer risk for TRD in major depressive disorder (MDD), a total of 948 MDD patients were recruited in a 12-week, multicenter, prospective longitudinal study.

RESULTS

Our study showed a significant allelic association between rs1565445 and TRD with an excess of the T allele in the TRD group, compared to non-TRD group (OR = 1.43, 95%CI: 1.16-1.76, p = 0.0008); while patients with genotype C/C and T/C in rs1565445 were less likely to develop TRD than those carrying T/T (OR = 0.52, 95%CI: 0.33-0.82; OR = 0.72, 95%CI: 0.54-0.97, respectively; p = 0.005). Haplotype T-T (rs1565445 and rs1387923) had 1.41-fold increased risk of TRD (p = 0.0014). Furthermore, significant four-locus (rs1387923-rs1565445-rs2769605-rs6265) gene-gene interactions were detected by the Multifactor-dimensionality reduction (MDR) method.

DISCUSSION

These results suggest that the interactions of BDNF (rs6265) with NTRK2 (rs1387923, rs2769605 and rs1565445) gene polymorphisms likely play an essential role in the development of TRD in Han Chinese MDD patients.

Clinical factors leading to lamotrigine prescription in bipolar outpatients: subanalysis of the SIN-DEPRES study

BACKGROUND

The use of lamotrigine is a point of discrepancy among the diverse guidelines published on the management of bipolar disorder (BD). Evidence supporting the long-term efficacy is reasonably robust. Nonetheless, the effectiveness of lamotrigine in acute treatment is vigorously debated and it is unclear how this drug is used in routine clinical practice. This subanalysis of the SIN-DEPRES study was designed to understand the clinical profile of bipolar patients receiving lamotrigine.

METHODS

In this prospective national multicenter study, 652 patients with clinically stable bipolar I and II disorder were recruited. Clinical assessments included sociodemographic and clinical data, the Modified Clinical Global Impression scale for BD (CGI-BP-M), the Hamilton Depression Rating Scale (HDRS), and prescriptions of psychotropic medications and their doses.

RESULTS

By means of a logistic regression model, an association between receiving treatment with lamotrigine and the following clinical variables was found: number of past depressive episodes (O.R.=2.875, 95% CI: 1.203-6.869, p=0.018), depressive polarity of the most recent episode (O.R.=1.945, 95% CI: 1.267-2.985, p=0.002), severity in CGI-BD-M depression (O.R.=1.850, 95% CI: 1.215-2.817, p=0.004), bipolar II disorder diagnosis (O.R.=1.635, 95% CI: 1.078-2.482, p=0.021) and number of episodes per year (O.R.=1.310, 95% CI: 1.069-1.605, p=0.009).

LIMITATIONS

Subanalysis of the SIN-DEPRES study with a cross-sectional design.

CONCLUSIONS

The use of lamotrigine in clinical practice is in accordance with most of the guidelines, which support its use in patients with depressive predominant polarity and bipolar II disorder.

Treatment-resistant depression: therapeutic trends, challenges, and future directions

BACKGROUND

Patients with major depression respond to antidepressant treatment, but 10%-30% of them do not improve or show a partial response coupled with functional impairment, poor quality of life, suicide ideation and attempts, self-injurious behavior, and a high relapse rate. The aim of this paper is to review the therapeutic options for treating resistant major depressive disorder, as well as evaluating further therapeutic options.

METHODS

In addition to Google Scholar and Quertle searches, a PubMed search using key words was conducted, and relevant articles published in English peer-reviewed journals (1990-2011) were retrieved. Only those papers that directly addressed treatment options for treatment-resistant depression were retained for extensive review.

RESULTS

Treatment-resistant depression, a complex clinical problem caused by multiple risk factors, is targeted by integrated therapeutic strategies, which include optimization of medications, a combination of antidepressants, switching of antidepressants, and augmentation with non-antidepressants, psychosocial and cultural therapies, and somatic therapies including electroconvulsive therapy, repetitive transcranial magnetic stimulation, magnetic seizure therapy, deep brain stimulation, transcranial direct current stimulation, and vagus nerve stimulation. As a corollary, more than a third of patients with treatment-resistant depression tend to achieve remission and the rest continue to suffer from residual symptoms. The latter group of patients needs further study to identify the most effective therapeutic modalities. Newer biomarker-based antidepressants and other drugs, together with non-drug strategies, are on the horizon to address further the multiple complex issues of treatment-resistant depression.

CONCLUSION

Treatment-resistant depression continues to challenge mental health care providers, and further relevant research involving newer drugs is warranted to improve the quality of life of patients with the disorder.