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Table 1 Innovation in psychopharmacology proceeds bottom-up more frequently than top-down in the levels of evidence

From: The ethics of clinical innovation in psychopharmacology: Challenging traditional bioethics

Level I: Double-blind randomized trials

Ia: Placebo-controlled

 

Ib: Non placebo-controlled

Level II: Open randomized trials

 

Level III: Naturalistic studies

IIIa: Nonrandomized, controlled studies

 

IIIb: Large nonrandomized, uncontrolled studies (n > 100)

 

IIIc: Medium-sized nonrandomized, uncontrolled studies (100 > n > 50)

Level IV: Small naturalistic studies (nonrandomized, uncontrolled, (50 > n > 10)

Level V: Case series (n < 10), Case report (n = 1), Expert opinion

Adapted by us from principles of Evidence-based Medicine [9]

In terms of the timeline of how the discovery process proceeds, this schema is inverted. Everything begins at level V with novel observations and clinical innovation, and proceeds upwards. Putting emphasis on the utility of controlled studies should not lead to the conclusion that research simply consists of doing controlled studies.