The Swiss Psychedelic Side Effects Inventory (SPSI) is a standardized questionnaire for systematically measuring side effects from psychedelics and MDMA. It was developed using previous data on side effects, pilot data from three studies, and structured expert feedback.

The SPSI assesses 32 of the most clinically relevant side effects and includes additional questions about side effect severity, subjective impact, duration, and likelihood of being drug-related. It takes about 15 minutes to complete and can be given as an interview or self-report in any study design and at any time after treatment with psychedelics or MDMA.

The SPSI was first presented at the 2024 Interdisciplinary Conference on Psychedelic Research (ICPR) in Haarlem, Netherlands.

Reference: Calder, A., & Hasler, G. (2024). Validation of the Swiss Psychedelic Side Effects Inventory: Standardizing reporting of adverse effects in studies of psychedelics and MDMA. Journal of Affective Disorders, 365, 258-264.

Downloads & Resources

View the SPSI below, or click the links to download it in either English or German.

Swiss Psychedelic Side Effects Inventory – English

Swiss Psychedelic Side Effects Inventory – Deutsch

An example of the completed and scored SPSI questionnaire can be found below:

SPSI Example – EN

SPSI Beispiel – DE