Electrical weapons and excited delirium: shocks, stress, and serum serotonin


It has been suggested that a CEW (conducted electrical weapon) exposure could elicit a stress response that could cause ExDS (excited delirium syndrome). There are some parallels between the signs of ExDS and serotonin syndrome (SS). Electroconvulsive therapy raises serotonin levels and therefore provides a plausible link between CEW applications and elevated serotonin levels. This study was designed to determine whether a CEW exposure elevates serum serotonin. A total of 31 police academy cadets were exposed to a very broad-spread 5-s CEW stimulus from a TASER brand X26 CEW. Blood was drawn before and after the exposure and at 24 h post exposure to measure serum serotonin levels. Lactic acid and cortisol levels were also compared. Median serum serotonin levels were 30 IQR (21,46), 36 IQR (22,50), and 32 IQR (21,45) ng/mL before exposure, after exposure, and 24 h after exposure (NS by pooled comparisons). The increase from baseline to post-test serotonin (∆ median = +6, ∆ mean = +2.7) ng/mL was not significant by a paired T-test (p = .29) but was significant by the Wilcoxon signed-rank test (p = .037). The increase to post-test log serotonin was not significant by a paired T-test (p = .13) but was significant by the Wilcoxon test (p = .049). All serotonin levels remained within the normal reference range of 0–200 ng/mL. Post-hoc analysis demonstrated that the study was powered to detect a ½ SD change, in log serotonin, with a 90% likelihood. With a very-broad electrode spread, CEW exposure did not significantly raise serum serotonin levels.

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Unites States Joint Non-Lethal Weapons Program. W911QY-08-C-0023.

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Corresponding author

Correspondence to Mark W. Kroll.

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Conflict of interest

Authors 1, 2, and 4 have been expert witnesses in use-of-force litigation. Author 1 is a member of the scientific advisory and corporate boards of Axon Enterprises, Inc. (fka TASER Intl, Inc.).

Ethical approval

Institutional Review Board of Texas A&M University.

Informed consent

Consent forms were obtained from all subjects before inclusion in this study. Participants were cadets from the Austin (Texas) Police Academy who had previously volunteered to undergo a CEW exposure as part of their training.

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Kroll, M.W., Hail, S.L., Kroll, R.M. et al. Electrical weapons and excited delirium: shocks, stress, and serum serotonin. Forensic Sci Med Pathol 14, 478–483 (2018). https://doi.org/10.1007/s12024-018-0005-8

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  • Force
  • Weapon
  • CEW
  • Serotonin
  • Excited delirium