Platseebokontrolli

Platseebokontrolli refers to a study design used in clinical trials in which participants are randomly assigned to receive either the active intervention or a placebo that resembles the active treatment. The purpose is to distinguish the true pharmacological or therapeutic effect from the placebo effect, which can arise from expectations, attention, and natural variation in symptoms.

Implementation generally involves randomization and blinding. In a typical placebo-controlled trial, the placebo is designed to look, taste, and be administered identically to the active treatment, and participants—and often researchers and clinicians—are unaware of assignment (double-blind). Outcomes are analyzed according to the intention-to-treat principle to preserve randomization. Placebos can be used in drug trials, surgical trials with sham procedures, and other interventions where a convincing sham is possible.

Ethical considerations are central. Placebo controls are most appropriate when no proven effective therapy exists or when withholding treatment would not expose patients to unnecessary harm. When effective standard treatments exist, active-control or add-on designs may be preferred. Informed consent, risk minimization, and independent ethical review are typical requirements, and trials may include rescue provisions if participants deteriorate.

Limitations include the possibility that nocebo effects or unblinding can bias results, and the setting and patient population may affect generalizability. Placebo-controlled trials may be impractical or unethical for certain conditions, and regulatory agencies weigh the balance of risks and benefits when recommending their use.

See also: placebo, randomized controlled trial, blinding.