Single low doses of LSD increase reward-related brain activity in healthy adults. In a double-blind, placebo-controlled experiment, 18 participants received 13 μg or 26 μg of LSD or a placebo across three sessions. Brain electrical activity was recorded during a monetary incentive delay task. Compared to placebo, the 13 μg dose enhanced three event-related potential components: Reward-Positivity (RewP), Feedback-P3 (FB-P3), and Late-Positive Potential (LPP), indicating increased hedonic, motivational, and affective processing of reward feedback. The 26 μg dose also increased FB-P3 amplitudes for positive feedback. These effects were not linked to most subjective drug effects. The findings provide the first evidence that low LSD doses boost reward-related brain activity, with potential implications for treating depressive disorders.
A low dose of LSD (26 micrograms) altered brain responses to reward feedback in people with mild-to-moderate depression, compared to those without depression. In depressed participants, LSD increased a brain signal called the late positive potential (LPP) when they received loss feedback, suggesting enhanced emotional processing of rewards. This change was linked to immediate positive mood and lower depressed mood two days later. Across all participants, LSD reduced other reward-related brain signals. The findings cautiously support the idea that low-dose LSD may have antidepressant effects.