Case report

A case report is a published account of one patient's clinical course, typically written because something unexpected happened — an unusual reaction, a rare adverse effect, or a presentation the treating clinician believed others should know about. It is the most granular unit of medical literature: a description of a single event, structured as a timeline of symptoms, treatments, and outcomes.

Within the evidence hierarchy, case reports sit near the base. They are not experiments; they record what happened, not what would happen under controlled conditions. Journals publish them because the singular can be informative when it concerns something genuinely rare or previously unobserved. Substance pages on Psychedex cite them most often when describing adverse effects or interactions that have not been formally studied.

What this design can establish

A case report can establish that a specific outcome is pharmacologically possible — that a seizure, an adverse reaction, or an unexpected effect actually occurred in a documented patient. It can establish temporal sequence: the event followed the exposure. That is different from establishing causation, but sequence is itself informative.

Case reports are particularly valuable as early signals for rare harms. A cluster of independently filed reports naming the same drug and the same outcome is often the first indication that a relationship is worth investigating formally. They anchor the case series and, eventually, the cohort study that can begin to quantify risk.

What it cannot

A single case report cannot establish how often an outcome occurs, which patients are at risk, or whether the drug caused the event rather than coincided with it. The patient described may have had pre-existing conditions, concurrent medications, or other exposures that drove the outcome. Without a comparison group, there is no way to know whether the same event would have occurred without the drug.

The inference a reader is most likely to make — "this drug causes X" — is not supportable from one report. What the report actually supports is narrower: X was observed after this drug was used, in this patient, on this occasion. That distinction matters when evaluating the evidence cited on these pages.

When no case reports exist for a given substance or combination, that is also a real statement about the record. Absence of published cases may mean the combination has not produced events dramatic enough to prompt a write-up, or simply that no one has looked — not that the combination is proven safe.