Letter: How blind is the double-blind?: an assessment in a lithium-prophylaxis study

Pharmacologic agents for the treatment of acute bipolar mania

The knowledge base regarding the medical treatment of acute bipolar mania is rapidly expanding. Information about agents with established antimanic properties is increasing, and more agents with putative antimanic properties are being identified. We first review the controlled studies supporting the efficacy of the established antimanic agents lithium, valproate, and carbamazepine and standard antipsychotics. We then review available research on two important classes of drugs that are emerging as potential treatments for acute mania: the novel antipsychotics, which include clozapine, olanzapine, quetiapine, risperidone, and ziprasidone, and the new antiepileptics, which include gabapentin, lamotrigine, oxcarbazepine, tiagabine, topiramate, and zonisamide. We conclude that although controlled data are accumulating to support the efficacy of several atypical antipsychotics in the treatment of acute bipolar mania, particularly olanzapine, ziprasidone, and risperidone, the novel antiepileptics need more extensive study before it can be concluded that any of them possess specific antimanic properties. We also conclude that as the medical options for acute bipolar mania expand, treatment guidelines must remain both evidence based and flexible, so that they represent cutting edge medical science yet can be tailored to the specific needs of individual patients.

Placebo effect in randomized, controlled studies of acute bipolar mania and depression

Randomized, double-blind, placebo-controlled, parallel group clinical trials have been the standard methodology for establishing the efficacy of new treatments for patients with bipolar disorder in manic, mixed, or depressive episodes. We examine the placebo response rate in acute treatment trials of acute mania (and mixed states) and bipolar depression. Also addressed are potential variables associated with placebo response, strategies to minimize placebo response, the optimum duration of placebo-controlled acute treatment trials, possible alternatives to the use of placebo, and the ramifications of these issues with regard to the design of studies in children, adolescents, and older adults with bipolar disorder.

An evaluation of the double-blind design in a study comparing lithium carbonate with placebo

As part of a study of drug treatment of aggressive behavior to be reported separately, we have evaluated the double-blind procedure in a recently completed comparison of the efficacy of lithium carbonate versus placebo in modifying aggressive behavior in nonpsychotic incarcerated delinquents. We conclude that the side effects of lithium carbonate are sufficient to reveal the medication to most subjects receiving it. Thus, while the study staff could not identify lithium-receivers at better than chance levels, and while subjects who received placebo could not identify their medication at better than chance levels, subjects who received lithium could accurately identify it. On a weekly symptom check list there was no difference between lithium and placebo groups on average lithium target symptoms reported during 4-week pre- and postmedication control periods; however, lithium-receivers reported significantly more target symptoms every week medication was administered. Of 16 subjects who quit the study, 14 had received lithium and nearly all of those who gave reasons for quitting specified side effects, most often nausea. The methodological problems of using lithium in a double-blind design might be overcome by employing a "discontinuation" design, or, speculatively, a double-blind, cross-over design utilizing an "active placebo".

Double-blind procedure: an assessment in a study of lithium prophylaxis

Fifty-seven patients with primary affective disorder who were in a double-blind outpatient study to evaluate the prophylaxis of lithium were questioned as to whether they believed they were receiving lithium or placebo. Research nurses who were 'blind' to the patients' medication and a close relative living with each patient were also questioned. Nearly all patients (96%) said they beleived they were receiving lithium, ascribing this belief in 63% of the cases to a perceived improvement in condition. In only 14% of the cases on lithium was the presence of side-effects implicated in the patients' beliefs. One of the three nurses had a correct guess rate in excess of chance expectancy. All nurses tended to be more accurate in their guesses in the cases of patients who had been in prophylactic trials of over 15 months' duration than for patients with briefer periods in the study. Patients' relatives were, as a group, extremely accurate, their correct guess rate exceeding chance expectancy at the 0-001 level.