Deliriants are a class of hallucinogen. The term was introduced by David F. Duncan and Robert S. Gold to distinguish these drugs from psychedelics and dissociatives, such as LSD and ketamine respectively, due to their primary effect of causing delirium, as opposed to the more lucid states produced by other hallucinogens (psychedelics and dissociatives). The term is generally used to refer to anticholinergic drugs.
The delirium produced is characterized by stupor, confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking. Other commonly reported behaviors include holding full conversations with imagined people, finishing a complex, multi-stage action (such as getting dressed) and then suddenly discovering one had not even begun yet, and being unable to recognize one's own reflection in a mirror.
The effects have been linked to sleepwalking, a fugue state or a psychotic episode (particularly in that the subject has minimal control over their actions and little to no recall of the experience). This is a notable departure from the effects of serotonergic psychedelics.
Naturally occurring deliriants are found in plant species such as Atropa belladonna (deadly nightshade), various Brugmansia species (Angel's Trumpets), Datura stramonium (Jimson weed), Hyoscyamus niger (henbane), and Mandragora officinarum (mandrake) in the form of tropane alkaloids (notably atropine, scopolamine, and hyoscyamine). Synthetic compounds such as diphenhydramine (Benadryl) and dimenhydrinate (Dramamine) are also deliriants. Additionally, the mushroom referred to as fly agaric and its active principles ibotenic acid and muscimol may also be considered deliriants, albeit with a unique biological mechanisms of action.
Despite the fully legal status of several common deliriant plants, deliriants are largely unpopular as recreational drugs due to the severe and sometimes unpleasant nature of the hallucinations produced.
User reports of recreational deliriant usage on the Erowid website generally indicate a firm unwillingness to repeat the experience. In addition to their potentially dangerous mental effects (accidents during deliriant experiences are common) some tropane alkaloids are poisonous and can cause death due to tachycardia-induced heart failure and hyperthermia even in small doses.
Disubstituted glycolic acid esters: