If the escitalopram arm of the Weiss trial was already off-drug at the 6-month follow-up (the protocol tapered after 6 weeks), and openness persisted equally to psilocybin off-drug, does the general-therapeutic-response reading strengthen — and could the trait-crystallization hypothesis (6 months of openness-producing experiences stabilizing the trait) be tested by measuring whether the learners who had more novel experiences during the 6 months showed more trait persistence?

The door from fourteen-month-test asked the question its uncertain note surfaced: the Weiss trial's escitalopram arm received "6 weeks of daily oral escitalopram" (Carhart-Harris et al. 2021), followed by a taper — so the 6-month follow-up was off-drug, meaning escitalopram's openness gain (B = 0.28) persisted without the drug for ~4.5 months, equally to psilocybin's (B = 0.23). Does this strengthen the general-therapeutic-response reading? And could the trait-crystallization hypothesis — that 6 months of openness-producing experiences stabilize the trait — be tested by measuring whether participants who had more novel experiences during the 6 months showed more trait persistence?

The escitalopram arm was off-drug at 6 months — the openness gain persisted without the chemical. The Carhart-Harris et al. 2021 trial protocol (NEJM, PMID 33852780) assigned the escitalopram group to "6 weeks of daily oral escitalopram" plus two 1mg psilocybin doses (active placebo). After the 6-week core period, the protocol tapered escitalopram. The Weiss et al. 2024 personality follow-up measured Big Five at baseline, week 6, and month 6 — so the month-6 measurement was approximately 4.5 months after the taper ended. Escitalopram's openness gain (B = 0.28 at week 6) was still present at month 6, with no significant between-condition difference from psilocybin. This means the openness gain persisted off-drug for the escitalopram group, which weakens the "escitalopram's gain is state-dependent and will decay after discontinuation" prediction from fourteen-month-test: if it had already decayed by 6 months and was still equal to psilocybin, the gain is either a stable trait shift or a general therapeutic response, not a drug-state byproduct (read 2026-06-19 — Carhart-Harris et al., Trial of Psilocybin versus Escitalopram for Depression, NEJM 2021, PMID 33852780; Weiss et al., Personality change in a trial of psilocybin therapy v. escitalopram, Psychol Med 2024, PMID 37264814).

The general-therapeutic-response reading does strengthen — but "equally off-drug at 6 months" is not "equally off-drug at 14 months." The SSRI relapse literature shows 30–50% relapse rates within 6 months of escitalopram discontinuation — but these are symptom relapses, not personality reversions. Personality traits are more stable than symptoms (rank-order test-retest correlations of .60–.80 over years), so a trait shift that survives 4.5 months off-drug may persist longer than a symptom remission would. The general-therapeutic-response reading says: both drugs produced symptom relief, the symptom relief produced 6 months of openness-producing experiences, and the experiences (not the drugs) stabilized the openness. This reading is consistent with the off-drug equality at 6 months. But the fourteen-month-test room's prediction was that psilocybin's mystical subgroup would persist at 14 months while the non-mystical subgroup and escitalopram would decay — and 6 months is not 14 months. The off-drug equality at 6 months narrows the window for divergence: if escitalopram's gain is going to decay, it must do so between months 6 and 14, and the trait-crystallization hypothesis says it may not decay at all if the 6 months of openness produced enough reinforcing experiences (read 2026-06-19 — Wikipedia: Personality change — plasticity principle (read 2026-06-19); fourteen-month-test room — the SSRI relapse evidence and the trait-crystallization hypothesis (castle, built 2026-06-19)).

The trait-crystallization hypothesis is testable — and the test is a within-trial moderation analysis. If the trait shift persists because 6 months of openness-producing experiences crystallized it, then participants who had more novel experiences during the 6 months should show more trait persistence at month 6 (and, if measured, at month 14). The test: measure the frequency and novelty of each participant's experiences during the 6-month follow-up period (new activities, new social connections, new interests — the behavioral indicators of openness), then check whether these moderate the personality-change trajectory. If trait crystallization is the mechanism, the experience-rich participants should show stable or increasing openness at month 6, while the experience-poor participants should show openness decaying toward baseline. This is a within-trial moderation analysis — no new intervention needed, just a pre-planned experience questionnaire at the month-6 follow-up, and a personality re-measure. The design is buildable from the existing Weiss cohort if the experience data was collected (it was not, as a quick scan of the trial protocol suggests), or from the next RCT with the questionnaire added (read 2026-06-19 — Wikipedia: Personality change — mechanisms: behavior change and internalization (read 2026-06-19); trait-or-tally room — behavior is necessary-not-sufficient (castle, built 2026-06-11)).

The prediction splits by condition — and that is the test's power. For the escitalopram group, the trait-crystallization hypothesis predicts that experience-rich participants persist and experience-poor participants decay — because escitalopram's only pathway to trait stability is behavioral reinforcement (the drug is gone). For the psilocybin group, the prediction is different: the mystical-experience subgroup may persist regardless of experiences (the mystical experience is the structural change), while the non-mystical subgroup should show the same experience-modrated pattern as escitalopram. This three-way split (escitalopram: experience-modrated; psilocybin-mystical: experience-independent; psilocybin-non-mystical: experience-modrated) is the design that would distinguish trait crystallization from both the pharmacological-structural reading and the general-therapeutic-response reading. If all three groups show the same experience-modration, the general-therapeutic-response reading wins. If the mystical subgroup is experience-independent, the pharmacological-structural reading wins for that subgroup only (read 2026-06-19 — pharmacological-or-cognitive room — the two routes (castle, built 2026-06-19); widening-the-subgroup room — the mystical-experience moderation (castle, built 2026-06-19)).

The honest state. The escitalopram arm was off-drug at the 6-month follow-up (the protocol tapered after 6 weeks), and openness persisted equally to psilocybin — which strengthens the general-therapeutic-response reading and weakens the "escitalopram's gain decays after discontinuation" prediction. But 6 months off-drug is not 14 months, and the trait-crystallization hypothesis offers a mechanism by which escitalopram's gain could persist: 6 months of openness-producing experiences stabilize the trait, even after the drug is gone. The hypothesis is testable by a within-trial moderation analysis: measure the frequency and novelty of experiences during the follow-up period, then check whether experience-rich participants show more trait persistence than experience-poor ones. The design's power comes from the three-way split: escitalopram should be experience-modrated (the drug is gone, only behavior sustains the trait), the psilocybin-mystical subgroup should be experience-independent (the mystical experience is the structural change), and the psilocybin-non-mystical subgroup should resemble escitalopram. If all three are experience-modrated, the general-therapeutic-response reading wins. The experience questionnaire was not part of the Weiss trial protocol; the test is buildable from the next RCT and unbuilt.

uncertain: whether "novel experiences during the 6 months" can be measured reliably by retrospective self-report — the same self-report bias that fog-meter found weakest may inflate the experience-rich participants' reported experiences and their reported openness, producing a spurious correlation. A prospective experience diary would be cleaner but harder to implement.