Feeling connected to a person during a conversation and feeling greater trust toward society are different outcomes. A supplied paper by Martinez and colleagues illustrates why those outcomes should remain separate: a small methamphetamine experiment found no significant improvement in broader subjective or social well-being after a structured conversation.
What did the methamphetamine experiment involve?
Study 2 included 20 healthy adults in a double-blind, counterbalanced comparison of 20 mg oral methamphetamine and placebo. Participants attended separate drug and placebo sessions and spoke for 45 minutes with a same-sex stranger who was a trained confederate. The conversation partner did not receive the drug and was unaware of the participant’s assigned condition.
The reported schedule placed capsule administration at 9:30 a.m., conversation onset at 10:40 a.m., and the later questionnaire assessment at 1:30 p.m. The paper describes its main broader well-being endpoint as approximately 90 minutes after the conversation. That timing should not be confused with a measurement taken immediately after swallowing the capsule or with a drug-free assessment days later.
The outcome was a questionnaire, not a behavior or concentration
The investigators used nine subscales from the Comprehensive Inventory of Thriving: trust, self-worth, life satisfaction, optimism, meaning, belonging, support, respect and engagement. Each subscale combined three self-report items rated on a five-point scale. The trust items addressed the broader social world, rather than only the immediate conversation partner.
The study therefore measured reported perceptions under a defined laboratory procedure. It did not measure driving, truthfulness, susceptibility to coercion, or the ability to give consent. No blood or oral-fluid concentration threshold for any of those capacities was established.
What did the null methamphetamine result look like?
The investigators found no significant methamphetamine–placebo differences in these broader well-being outcomes, whether comparing post-session ratings or changes from orientation. For trust gain scores, Table 3 reported means of −0.08 after methamphetamine and −0.12 after placebo, with standard deviations of 0.58 and 0.55, respectively; the paired analysis had p = .716.
That is evidence that this small experiment did not demonstrate an increase in global trust under its conditions. It is not an equivalence finding proving that the drug has precisely zero effect. A study of 20 participants leaves uncertainty about small effects, individual variation, different doses and other settings.
Why does the MDMA comparison need restraint?
Study 1 separately compared 100 mg oral MDMA with placebo in 15 analyzed participants. It reported higher global trust after MDMA, with p = .022, while its self-worth finding had p = .065 and did not meet the conventional .05 threshold. The paper presented several well-being outcomes; a positive result for one cannot be expanded into demonstrated improvement across all of them.
Crucially, the two drugs were tested in separate participant samples. Prior MDMA experience was required for the MDMA sample, whereas the recruitment criteria differed for the methamphetamine sample. The authors explicitly identified the need for a design permitting direct drug comparisons. A significant result in one sample and a nonsignificant result in another do not, by themselves, establish a statistically significant difference between the drugs.
How can sociability coexist with a global-trust null finding?
The authors explain that earlier analyses from the same experiments addressed connection and enjoyment during the conversations. Those immediate partner-focused outcomes and the later society-focused questionnaire concern different constructs. Treating publications from the same experiments as independent replications would also overstate the evidence base.
The practical lesson is to identify the exact outcome before making a claim about “social effects.” A person can describe a pleasant interaction without reporting a change in trust toward a neighborhood or society.
Limits on generalization
Participants were screened healthy volunteers, with exclusions for several psychiatric conditions and substance dependence. The dose was a single oral 20 mg administration. The findings cannot be transferred directly to smoked or injected exposure, repeated dosing, prolonged wakefulness, or clinical methamphetamine use disorder.
The later questionnaire could still reflect acute drug effects. The study did not demonstrate durable benefit after drug clearance. Its small samples, multiple outcomes, self-report measures and differences between the two experiments support cautious, outcome-specific interpretation.
Source
Martinez RL, Radošić N, Molla H, de Wit H, Lyubomirsky S. The empathogen 3,4-methylenedioxymethamphetamine, but not methamphetamine, increases feelings of global trust. Journal of Psychopharmacology. 2026;40(9):1361–1367; supplied article carries a 2025 copyright. doi:10.1177/02698811251370999. Two separate placebo-controlled human experiments; broader social outcomes from previously studied laboratory sessions.
Leave a Reply