Confusion is an impairment of abstract thinking demonstrated by an inability to think with one’s customary clarity and coherence.  Within the context of substance use, it is commonly experienced as a persistent inability to grasp or comprehend concepts and situations which would otherwise be perfectly understandable during sobriety. The intensity of this effect seems to to be further increased with unfamiliarity  in either setting or substance ingested.
Confusion is often accompanied by other coinciding effects such as delirium, delusions, and short-term memory suppression in a manner which further increases the person's lack of comprehension. It is most commonly induced under the influence of heavy dosages of hallucinogenic compounds, such as psychedelics  , dissociatives  , synthetic cannabinoids  , and deliriants   . However, it can also occur to a lesser extent under the influence of heavy dosages of benzodiazepines  and antipsychotics  .
- Burns, A., Gallagley, A., & Byrne, J. (2004). Delirium. Journal of Neurology, Neurosurgery & Psychiatry, 75(3), 362-367. | http://dx.doi.org/10.1136/jnnp.2003.023366
- Sheehan, P. W., & Lewis, S. E. (1974). Subjects' reports of confusion in consciousness and the arousal of imagery. Perceptual and Motor Skills, 38(3), 731-734. | https://doi.org/10.2466%2Fpms.1918.104.22.1681
- Krebs, T. S., & Johansen, P. Ø. (2013). Psychedelics and mental health: a population study. PloS one, 8(8), e63972. | https://doi.org/10.1371/journal.pone.0063972
- Mozayani, A. (2003). Phencyclidine-Effects on Human Performance and Behavior. Forensic science review, 15(1), 61-74. | https://www.ncbi.nlm.nih.gov/pubmed/26256594
- Chase, P. B., Hawkins, J., Mosier, J., Jimenez, E., Boesen, K., Logan, B. K., & Walter, F. G. (2016). Differential physiological and behavioral cues observed in individuals smoking botanical marijuana versus synthetic cannabinoid drugs. Clinical Toxicology, 54(1), 14-19. | https://doi.org/10.3109/15563650.2015.1101769
- Datura effects (Erowid) | https://erowid.org/plants/datura/datura_effects.shtml
- Nicholson, K. L., & Balster, R. L. (2001). GHB: a new and novel drug of abuse. Drug and alcohol dependence, 63(1), 1-22. | https://doi.org/10.1016/S0376-8716(00)00191-5