Environmental etiology of psychotic experiences in Ethiopia: Effects of khat use, trauma load and seasonality

Abstract

In Ethiopia, khat (Catha edulis) leaves, containing amphetamine-like alkaloids, are chewed for their psycho-stimulating effects. Khat use has been associated with psychosis. In a psychosis etiology framework, we investigated whether season, fluctuations of khat availability and khat use are associated with khat-induced psychotic experiences and whether trauma load moderates this association.

In Southwestern Ethiopia, a cohort of 685 men aged 18-40 years were interviewed twice, during dry and after rainy season (low vs. high khat availability). Khat use was assessed by urine immunoassay and self-report. Trauma load and psychotic experiences were assessed by trained local interviewers.

Khat use increased after the rainy season (p < 0.0001). Khat use and seasonality predicted khat-induced psychotic experiences. Main findings comprise increased odds of psychotic experiences among immunoassay-positive individuals with high trauma load. A potential additional interaction with recent trauma emerged. Findings support sensitization-related mechanisms but require replication in larger samples with longer follow-up.

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BibTeX RIS

BibTeX

@misc{odenwald2026environmental,
  title = {{Environmental etiology of psychotic experiences in Ethiopia: Effects of khat use, trauma load and seasonality}},
  author = {M. Odenwald and L. Oetzel and H. F. G. A. Atkinson and M. Widmann and Z. Mekonnen and M. Soboka and V. Mueller-Bamouh and S. Suleman and F. Tessema and S. W. Toennes and M. Mattheisen and T. G. Schulze and M. Tesfaye and K. Adorjan},
  howpublished = {medRxiv},
  year = {2026},
  month = sep,
  doi = {10.64898/2026.09.27.26364112},
  url = {https://www.medrxiv.org/content/10.64898/2026.09.27.26364112v1},
  note = {CC BY-NC-ND},
}

RIS

TY  - UNPB
TI  - Environmental etiology of psychotic experiences in Ethiopia: Effects of khat use, trauma load and seasonality
AU  - M. Odenwald
AU  - L. Oetzel
AU  - H. F. G. A. Atkinson
AU  - M. Widmann
AU  - Z. Mekonnen
AU  - M. Soboka
AU  - V. Mueller-Bamouh
AU  - S. Suleman
AU  - F. Tessema
AU  - S. W. Toennes
AU  - M. Mattheisen
AU  - T. G. Schulze
AU  - M. Tesfaye
AU  - K. Adorjan
PY  - 2026
DA  - 2026/09/27
PB  - medRxiv
DO  - 10.64898/2026.09.27.26364112
UR  - https://www.medrxiv.org/content/10.64898/2026.09.27.26364112v1
AB  - In Ethiopia, khat (Catha edulis) leaves, containing amphetamine-like alkaloids, are chewed for their psycho-stimulating effects. Khat use has been associated with psychosis. In a psychosis etiology framework, we investigated whether season, fluctuations of khat availability and khat use are associated with khat-induced psychotic experiences and whether trauma load moderates this association.  In Southwestern Ethiopia, a cohort of 685 men aged 18-40 years were interviewed twice, during dry and after rainy season (low vs. high khat availability). Khat use was assessed by urine immunoassay and self-report. Trauma load and psychotic experiences were assessed by trained local interviewers.  Khat use increased after the rainy season (p < 0.0001). Khat use and seasonality predicted khat-induced psychotic experiences. Main findings comprise increased odds of psychotic experiences among immunoassay-positive individuals with high trauma load. A potential additional interaction with recent trauma emerged. Findings support sensitization-related mechanisms but require replication in larger samples with longer follow-up.
ER  -

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