Efficient trial designs to reduce placebo requirements

Testosterone and libido in surgically and naturally menopausal women

The assessment and then treatment of a change in libido, or a change in the desire to partake in sexual activity, during the menopausal transition and beyond has been a challenging and elusive area of clinical research. This is partly due to the multidimensional nature of female sexuality, the difficulties of measuring testosterone in women in a reliable and accurate manner, and the complexity of the neurobiology and neurobehavior of female sexual desire. In addition, there is a lack of evidence for diagnostic specificity of low free testosterone levels for the symptom of low libido in women for whom there are no confounding interpersonal or psychological factors; although, in the symptomatic population of surgically or naturally menopausal women, a low level of free testosterone often accompanies a complaint of reduced desire/libido. The randomized clinical trial research on testosterone replacement for naturally and/or surgically menopausal women with sexual dysfunction has been criticized for a high placebo response rate, supraphysiological replacement levels of testosterone, the perception of modest clinical outcome when measuring objective data such as the frequency of sexual intercourse relative to placebo, and the unknown safety of long-term testosterone replacement in the estrogen-replete surgically or naturally menopausal woman. A careful review of current evidence from randomized, controlled trials lends support to the value of the replacement of testosterone in the estrogen-replete menopausal woman for whom libido and desire has declined. The issue of long-term safety remains to be answered.

Placebo response in depression

With its naturally fluctuating course, depression is a highly placebo-responsive condition: mean placebo response rates in antidepressant clinical trials are 30% to 40%. We review the history and terminology of placebo and the proposed mechanisms underlying the placebo response, including the physician-patient relationship and biological, sociocultural, and treatment situation factors. We identify the predictors and patterns of placebo response in depressed patients, both within and outside of the clinical trial context, and differentiate between true drug response and placebo pattern response. We discuss the strategies now being advanced to minimize the placebo response given the increased placebo drift reported in recent trials, and the ethical guidelines governing placebo administration. Potential areas for future research include the identification of biological markers of placebo response, such as functional neuroimaging and quantitative electroencephalography, the development and testing of more sophisticated, alternative research designs, and the design of valid biological tools to assess antidepressant efficacy.

A systematic review of antidepressant placebo-controlled trials for geriatric depression: limitations of current data and directions for the future

Depression in the elderly is a major public health problem as untreated depression adversely impacts comorbid illnesses. It is important to develop safe and effective antidepressant therapies for older individuals. We performed a systematic review of all published randomized, placebo-controlled antidepressant medication trials in populations over age 55 years. Papers were obtained via MEDLINE (1966-August 2003) and PSYCINFO (1872-August 2003). Unpublished trials, trials examining nonpharmacologic interventions, and papers reporting post hoc analyses were not included in this review unless they provided new insights. A total of 18 placebo-controlled trials examining acute efficacy met our criteria. The combined sample size in these studies was 2252. The mean sample size was 51 (range 20-728) and mean trial duration was 7 weeks. A total of 12 trials examined tricyclic antidepressants (TCAs), five trials examined selective serotonin reuptake inhibitors (SSRIs), two trials examined bupropion, and one trial examined mirtazapine. There were no published trials of venlafaxine or nefazodone. In all, 71.5% of trials reported significantly greater efficacy with drug than placebo. In conclusions, there is a paucity of published controlled antidepressant trials in the elderly. Most published studies examine small sample sizes and do not include common comorbid conditions. Efficacy studies examining relapse prevention are lacking. Large placebo response rates, lack of controlled head to head comparisons, and other methodological design differences make crosstrial comparisons difficult. Large simple studies are urgently needed to address the unmet needs for data on safety and efficacy of antidepressants in this population.

AACAP 2002 research forum: placebo and alternatives to placebo in randomized controlled trials in pediatric psychopharmacology

OBJECTIVE

The use of placebo in the pediatric age group has come under increasing scrutiny. At the 2002 Annual Meeting of the American Academy of Child and Adolescent Psychiatry, the Academy's Workgroup on Research conducted a research forum. The purpose was to identify challenges and their solutions regarding the use of placebo in randomized controlled trials in pediatric psychopharmacology.

METHOD

Workgroups focused on problems and solutions in five areas: ethics and human subjects, research design and statistics, partnering with consumers, U.S. Food and Drug Administration and pharmaceutical industry perspectives, and psychosocial treatments.

RESULTS

In many but not all circumstances, inclusion of a placebo control is essential to meet the scientific goals of treatment outcome research. Innovative research designs; involvement of consumers in planning and implementing research; flexibility by industry, academia, the National Institutes of Health, and regulatory agencies acting in partnership; and concomitant use of evidence-based psychosocial services can and should assist in making placebo-controlled trials acceptable.

CONCLUSIONS

Properly designed placebo-controlled trials remain necessary, ethical, and feasible.

The development, evolution and philosophy of a clinical research unit

OBJECTIVE

To describe the development,evolution and philosophy of a clinical research unit.

METHOD

The 20-year history of clinical psychiatric research in Christchurch is described. The variety of influences which have impacted upon the studies undertaken is acknowledged,as are the personal histories of key staff.

CONCLUSIONS

Clinical research is potentially endangered. The maintenance and development of clinical research requires a mix of individual inquisitiveness and determination,local opportunity and political will. Despite a political desire for evidence-based medicine; most political policies and practices impede the development of new knowledge and the collection of new evidence.

Placebos, placebo effect, and the response to the healing situation: the evolution of a concept

In spite of its impressive progress, medicine has been strongly criticized for relying on its modern biomedical tradition to the neglect of the psychosocial aspects of health. This neglect may account for patients' dissatisfaction and eventual use of alternative health approaches. The concept of placebo has sustained dramatic "protean" metamorphoses through the ages. For centuries, placebos have been regarded as powerful deceptive therapies. From the middle of the twentieth century, however, conventional medicine has used placebos as methodologic tools to distinguish the specific from the nonspecific ingredients in treatments. In modern medical research, the double-blind, placebo-controlled, randomized clinical trial has been established as the gold standard for the assessment of any new treatment. Recently a new trend regarding placebos seems to have emerged. The placebo and other nonspecific effects elicited by the "healing situation" have been independently subjected to scientific study. Progress in this area may promote useful clinical applications, enabling physicians to broaden their perspectives on the healing process. We present the historical changes of the concept of placebo and the ethical issues raised by their use.