Tal Burt

Neuropsychiatric applications of transcranial magnetic stimulation: a meta analysis

Transcranial magnetic stimulation (TMS) is a technology that allows for non-invasive modulation of the excitability and function of discrete brain cortical areas. TMS uses alternating magnetic fields to induce electric currents in cortical tissue. In psychiatry, TMS has been studied primarily as a potential treatment for major depression. Most studies indicate that slow-frequency repetitive TMS (rTMS) and higher frequency rTMS have antidepressant properties. A meta-analysis of controlled studies indicates that this effect is fairly robust from a statistical viewpoint. However, effect sizes are heterogeneous, and few studies have shown that rTMS results in substantial rates of clinical response or remission, and the durability of antidepressant effects is largely unknown. We review in detail rTMS studies in the treatment of depression, as well as summarize treatment studies of mania, obsessive-compulsive disorder, post-traumatic stress disorder, and schizophrenia. We also review the application of TMS in the study of the pathophysiology of psychiatric disorders and summarize studies of the safety of TMS in human subjects.

Vagus nerve stimulation: a new tool for brain research and therapy.

Biological psychiatry has a long history of using somatic therapies to treat neuropsychiatric illnesses and to understand brain function. These methods have included neurosurgery, electroconvulsive therapy, and, most recently, transcranial magnetic stimulation. Fourteen years ago researchers discovered that intermittent electrical stimulation of the vagus nerve produces inhibition of neural processes, which can alter brain electrical activity and terminate seizures in dogs. Since then, approximately 6000 people worldwide have received vagus nerve stimulation for treatment-resistant epilepsy. We review the neurobiology and anatomy of the vagus nerve and provide an overview of the vagus nerve stimulation technique. We also describe the safety and potential utility of vagus nerve stimulation as a neuroscience research tool and as a putative treatment for psychiatric conditions. Vagus nerve stimulation appears to be a promising new somatic intervention that may improve our understanding of brain function and has promise in the treatment of neuropsychiatric disorders.

Efficacy, Safety, and Tolerability of Sertraline in Patients with Late-Life Depression and Comorbid Medical Illness

Objectives: To report on the efficacy, safety, and tolerability of sertraline in the treatment of elderly depres‐sed patients with and without comorbid medical illness.

Mania associated with St. John's wort.

BACKGROUND St. Johns wort, the popular herbal remedy touted as an antidepressant, is generally thought to be benign, with few reported side effects. Given its possible efficacy as an antidepressant, evaluation of its propensity to cause affective switching should be evaluated. METHODS This report presents two cases of mania temporally associated with the use of St. Johns wort (hypericum). RESULTS As with other antidepressant agents, St. Johns wort may precipitate hypomania, mania, or an increased cycling of mood states, particularly in patients with occult bipolar disorder. CONCLUSIONS Because the majority of people who take this popular over-the-counter preparation do so without formal psychiatric evaluations, risk of hypericum-induced mania may be significant. Physicians should screen patients for a history of hypomania or mania before recommending use of St. Johns wort for depression.

Comparison of duloxetine, escitalopram, and sertraline effects on cytochrome P450 2D6 function in healthy volunteers

This study is the first to directly compare the relative effects of duloxetine, escitalopram, and sertraline on the functional activity of the drug-metabolizing cytochrome P450 2D6 enzyme as assessed by changes in the pharmacokinetics of the cytochrome P450 2D6 model substrate drug, metoprolol. Single-dose pharmacokinetics of metoprolol were measured before and after 17 days of treatment with escitalopram 20 mg/d, duloxetine 60 mg/d, or sertraline 100 mg/d in young healthy male and female participants. The outcome measures were changes in metoprolol peak plasma levels, area under the plasma concentration-time curve, and clearance. The results were tested using paired t tests and independent t tests. The addition of each drug produced statistically significant changes in metoprolol pharmacokinetics. The rank order for the change in metoprolol area under the plasma concentration-time curve was duloxetine (180%) > escitalopram (89%) > sertraline (48% and 67%). Compared with sertraline, duloxetine produced statistically significantly larger changes in metoprolol pharmacokinetic parameters. The changes produced by escitalopram and sertraline were not statistically different.

Late onset dysthymic disorder and major depression differ from early onset dysthymic disorder and major depression in elderly outpatients

BACKGROUND Age of onset may affect clinical features and prognosis in elderly patients with major depression (MDD), but there is a lack of such data in elderly patients with dysthymic disorder (DD) and systematic comparisons of late onset MDD and DD have not been conducted. METHODS In a Late Life Depression Clinic, patients > or = 60 years old who met DSM-III-R or DSM-IV criteria for MDD or DD were studied. The 24-item Hamilton Rating Scale for Depression (HRSD) and SCID-P were completed, family history was obtained, and medical illnesses were assessed. RESULTS In the total sample (n=370; 211 MDD and 159 DD), compared to early onset patients, late onset (onset > or =60 years) patients had a higher rate of cardiovascular disease (chi(2)=4.12, df=1, P<0.05), lower rate of anxiety disorder (chi(2)=4.19, df=1, P<0.05), and a lower rate of family history of affective disorder (chi(2)=9.37, df=1, P<0.002). Late onset DD patients were more likely to have cardiovascular disease than early onset DD patients (chi(2)=5.63, df=1, P<0.02), but the rate of cardiovascular disease did not differ between late and early onset MDD patients (chi(2)=0.35, df=1, P<0.6). Late onset MDD patients were less likely to have a family history of affective disorder than early onset MDD patients (chi(2)=10.71, df=1, P<0.001). Prevalence of anxiety disorders did not differ between the early and late onset MDD patients (chi(2)=0.07, df=1, P<0.79), but was more common in the early onset DD compared to the late onset DD patients (17.98% versus 4.29%, chi(2)=6.98, df=1, P<0.01). Late onset DD did not differ from late onset MDD in the rates of cardiovascular disease, anxiety disorders, and family history of affective disorder. Excluding patients with double depression (n=32) did not alter the cardiovascular or family history findings, but the difference in anxiety disorders between early and late onset DD patients was no longer significant. LIMITATIONS Academic clinic sample results may not generalize to community populations. CONCLUSIONS In the elderly, late-onset DD is typically different from early onset DD. Cerebrovascular disease appears to play a role in the etiology of late onset DD. The similarities between late onset DD and late onset MDD suggest a single condition along a continuum.

Microdosing and drug development: past, present and future.

Introduction: Microdosing is an approach to early drug development where exploratory pharmacokinetic data are acquired in humans using inherently safe sub-pharmacologic doses of drug. The first publication of microdose data was 10 years ago and this review comprehensively explores the microdose concept from conception, over the past decade, up until the current date. Areas covered: The authors define and distinguish the concept of microdosing from similar approaches. The authors review the ability of microdosing to provide exploratory pharmacokinetics (concentration-time data) but exclude microdosing using positron emission tomography. The article provides a comprehensive review of data within the peer-reviewed literature as well as the latest applications and a look into the future, towards where microdosing may be headed. Expert opinion: Evidence so far suggests that microdosing may be a better predictive tool of human pharmacokinetics than alternative methods and combination with physiologically based modelling may lead to much more reliable predictions in the future. The concept has also been applied to drug-drug interactions, polymorphism and assessing drug concentrations over time at its site of action. Microdosing may yet have more to offer in unanticipated directions and provide benefits that have not been fully realised to date.

Optimal length of antidepressant trials in late-life depression.

Abstract: There is a long-standing belief that elderly patients take longer to respond to antidepressant treatment than younger patients, and thus, require longer trials to respond or remit. This has led to the question: What is the minimum duration of antidepressant treatment necessary to identify responders in older depressed adults? A 12-week duration was tested based on 2 separate ideas: (1) older patients take longer to respond and, therefore, require longer trials to achieve optimal response (ie, remission), and (2) patients who are still quite symptomatic at Week 11 may improve dramatically and meet response, or even remission, criteria by Week 12. The data that support these beliefs are sparse and what little exist are contradictory. Rates of response and time-to-response were analyzed in depressed older adults in two 12-week clinical trials. The results do not support the belief that older patients take longer to respond or that, generally, as a group, older patients have a lower response rate. Furthermore, if patients do not have ≥30% reduction in baseline Hamilton Rating Score for Depression (HRSD) by Week 4, the probability that they will meet remission criteria (defined as HRSD ≤10 and HRSD ≤6) at the end of the trial is only 35% and 16.5%, respectively. Therefore, a 12-week trial is not necessary for all older patients; rather, the degree of improvement in the first 4 to 6 weeks identifies patients who are highly likely to benefit from continuing antidepressant treatment as well as those who very probably should have their treatment regimen altered at that point.

Pharmacogenomics in early-phase clinical development.

Pharmacogenomics (PGx) offers the promise of utilizing genetic fingerprints to predict individual responses to drugs in terms of safety, efficacy and pharmacokinetics. Early-phase clinical trial PGx applications can identify human genome variations that are meaningful to study design, selection of participants, allocation of resources and clinical research ethics. Results can inform later-phase study design and pipeline developmental decisions. Nevertheless, our review of the clinicaltrials.gov database demonstrates that PGx is rarely used by drug developers. Of the total 323 trials that included PGx as an outcome, 80% have been conducted by academic institutions after initial regulatory approval. Barriers for the application of PGx are discussed. We propose a framework for the role of PGx in early-phase drug development and recommend PGx be universally considered in study design, result interpretation and hypothesis generation for later-phase studies, but PGx results from underpowered studies should not be used by themselves to terminate drug-development programs.

PARTAKE Survey of Public Knowledge and Perceptions of Clinical Research in India

Background A public that is an informed partner in clinical research is important for ethical, methodological, and operational reasons. There are indications that the public is unaware or misinformed, and not sufficiently engaged in clinical research but studies on the topic are lacking. PARTAKE – Public Awareness of Research for Therapeutic Advancements through Knowledge and Empowerment is a program aimed at increasing public awareness and partnership in clinical research. The PARTAKE Survey is a component of the program. Objective To study public knowledge and perceptions of clinical research. Methods A 40-item questionnaire combining multiple-choice and open-ended questions was administered to 175 English- or Hindi-speaking individuals in 8 public locations representing various socioeconomic strata in New Delhi, India. Results Interviewees were 18–84 old (mean: 39.6, SD±16.6), 23.6% female, 68.6% employed, 7.3% illiterate, 26.3% had heard of research, 2.9% had participated and 58.9% expressed willingness to participate in clinical research. The following perceptions were reported (% true/% false/% not aware): ‘research benefits society’ (94.1%/3.5%/2.3%), ‘the government protects against unethical clinical research’ (56.7%/26.3%/16.9%), ‘research hospitals provide better care’ (67.2%/8.7%/23.9%), ‘confidentiality is adequately protected’ (54.1%/12.3%/33.5%), ‘participation in research is voluntary’ (85.3%/5.8%/8.7%); ‘participants treated like ‘guinea pigs’’ (20.7%/53.2%/26.0%), and ‘compensation for participation is adequate’ (24.7%/12.9%/62.3%). Conclusions Results suggest the Indian public is aware of some key features of clinical research (e.g., purpose, value, voluntary nature of participation), and supports clinical research in general but is unaware of other key features (e.g., compensation, confidentiality, protection of human participants) and exhibits some distrust in the conduct and reporting of clinical trials. Larger, cross-cultural surveys are required to inform educational programs addressing these issues.