# Video research-update insert: Psilocybin, Cortical Plasticity and Durable Antidepressant Response

Editorial script and storyboard insert, 5 October 2026. No rendered video. Read alongside the original review; no new grade is announced.

## Narration

Clinical trials support symptom effects in selected settings, and mouse experiments establish specific receptor/cell dependencies. These findings do not yet show that a temporary rise in human structural plasticity mediates lasting antidepressant benefit; recent null and context-dependent results are central to that distinction.

In the 2016 study, symptoms improved after psilocybin with psychological support. Small uncontrolled study cannot separate drug, expectancy, support and natural course. [P27210031]

In the 2023 study, depressive symptoms and disability improved through the measured follow-up. Acute experiential differences and psychological support complicate causal component separation. [P37651119]

In the 2026 study, the report found no significant overall synaptic-density increase; setting-related differences were observed. Small context-dependent before/after study is not a randomized mediator test or universal absence of plasticity. [P42457666]

The next discriminating question is: Does structural plasticity mediate human clinical benefit? Functional adaptation or support-related learning may matter without increased synaptic density. Randomized clinical studies with time-ordered orthogonal plasticity measures, functional readouts and symptoms; complement with selective mediator perturbation in models.

The timeline shows selected changes in evidence, not inevitable progress or proof of a single cause. The review’s archived grade remains unchanged; the depth of source reading is documented in the update.

## Storyboard and source locks

| Insert | Visual | Narration anchor | Sources |
|---|---|---|---|
| Opening | Claim and bounded update statement | First paragraph | Review claim and source ledger |
| Timeline 2016 | Dated study card with design, result and limit | Symptoms improved after psilocybin with psychological support. | [P27210031](https://pubmed.ncbi.nlm.nih.gov/27210031/) |
| Timeline 2023 | Dated study card with design, result and limit | Depressive symptoms and disability improved through the measured follow-up. | [P37651119](https://pubmed.ncbi.nlm.nih.gov/37651119/) |
| Timeline 2026 | Dated study card with design, result and limit | The report found no significant overall synaptic-density increase; setting-related differences were observed. | [P42457666](https://pubmed.ncbi.nlm.nih.gov/42457666/) |
| G1 | Question → competing explanation → discriminating test | Does structural plasticity mediate human clinical benefit? | [P34228959](https://pubmed.ncbi.nlm.nih.gov/34228959/), [P40175553](https://pubmed.ncbi.nlm.nih.gov/40175553/), [P41224969](https://pubmed.ncbi.nlm.nih.gov/41224969/), [P42457666](https://pubmed.ncbi.nlm.nih.gov/42457666/) |
| G2 | Question → competing explanation → discriminating test | Which component is drug action versus expectancy and support? | [P27210031](https://pubmed.ncbi.nlm.nih.gov/27210031/), [P33852780](https://pubmed.ncbi.nlm.nih.gov/33852780/), [P37651119](https://pubmed.ncbi.nlm.nih.gov/37651119/) |
| G3 | Question → competing explanation → discriminating test | Which receptor/cell dependency translates to humans? | [P40175553](https://pubmed.ncbi.nlm.nih.gov/40175553/), [P42457666](https://pubmed.ncbi.nlm.nih.gov/42457666/), [P34228959](https://pubmed.ncbi.nlm.nih.gov/34228959/) |
| G4 | Question → competing explanation → discriminating test | How durable are benefits and who is harmed or fails to respond? | [P36322843](https://pubmed.ncbi.nlm.nih.gov/36322843/), [P42138922](https://pubmed.ncbi.nlm.nih.gov/42138922/), [P37651119](https://pubmed.ncbi.nlm.nih.gov/37651119/), [P33852780](https://pubmed.ncbi.nlm.nih.gov/33852780/) |

## Editorial constraints

- Use the primary-source links shown above and keep the inference limit on screen with each milestone.
- Do not narrate an abstract check as complete-paper examination, a model result as human proof, or an unresolved inference as absence of all research.
- Preserve trial endpoint hierarchy, cohort reuse, correction notices and online/issue dates.
- Use original graphics made from this ledger. Publisher figure imagery has not been cleared or supplied for video reuse.
- Confirm any change in verdict through a separate documented HSEF review; this insert makes none.