Two men have suffered terrifying visual and auditory hallucinations after eating a popular local seafish in Mediterranean restaurants.
According to a clinical study on the patients, which is due to be published in the journal Clinical Toxicology, the men started seeing and hearing things after contracting a rare form of hallucinogenic poisoning from the Salema fish they were dining on.
The species is a popular food fish and is not normally hallucinogenic.
Ichthyoallyeinotoxism, or hallucinogenic fish poisoning, is caused by eating the heads or body parts of certain species of herbivorous fish and has previously only been recorded from the Indo Pacific.
The effects of eating ichthyoallyeinotoxic fishes, such as certain mullet, goatfish, tangs, damsels and rabbitfish, are believed to be similar to LSD, and may include vivid and terrifying auditory and visual hallucinations. This has given rise to the collective common name for ichthyoallyeinotoxic fishes of "dream fish".
Pommier and de Haro of the Toxicovigilance Centre Antipoison at Marseille's Hospital Salvator, who undertook the study, said that the men had both eaten a fish called Sarpa salpa, and subsequently suffered from CNS disturbances including terrifying hallucinations and nightmares.
One of the men, a 40-year old, was admitted to hospital suffering from a digestive problem and frightening visual and auditory hallucinations, which took 36 hours to disappear. The second man, a 90-year old, suffered from auditory hallucinations a couple of hours after eating the same species of fish, followed by a series of nightmares over the next two nights.
The poisoning can start to cause vivid hallucinations within minutes of eating a poisonous fish and may last for days, often with no other effects. There is no antidote.
IchthyoallyeinotoxismIndoles, with similar chemical effects to LSD (lysergic acid diethylamide) are believed to be responsible and may be consumed when the fish eat algae or phytoplankton containing the chemicals. All of the species effected by ichthyoallyeinotoxism are algal grazers.
Others have claimed that different species of ichthyoallyeinotoxic fishes, such as Kyphosus fuseus, contain much more potent hallucinogens, such as dimethyltryptamine or DMT, which is considered to be one of the world's most mind-bending hallucinogenic chemicals.
Sarpa salpaThe fish consumed by the men was a member of the Sparidae family and is commonly known as the Salema porgy.
The fish reaches a size of around 50cm/20" and occurs through much of the eastern Atlantic and Mediterranean. You can view the distribution of Sarpa salpa on Practical Fishkeeping's Fish Mapper.
According to the paper, Sarpa salpa was consumed as a recreational drug in the Med during the Roman Empire.
For more details on the hallucinatory fish poisonings see the paper: de Haro L, Pommier P (2006) - Hallucinatory fish poisoning (ichthyoallyeinotoxism): two case reports from the Western Mediterranean and literature review. Clin Toxicol (Phila). 2006;44(2):185-8.