In cases of serious poisoning the mushroom cause delirium , somewhat similar in effect to anticholinergic poisoning ( such as that caused by Datura stramonium ) , characterised by bouts of marked agitation with confusion , hallucinations , and irritability followed by periods of central nervous system depression . Seizures and coma may also occur in severe poisonings . Symptoms typically appear after around 30 to 90 minutes and peak within three hours , but certain effects can last for several days . In the majority of cases recovery is complete within 12 to 24 hours . The effect is highly variable between individuals , with similar doses potentially causing quite different reactions . Some people suffering intoxication have exhibited headaches up to ten hours afterwards . Retrograde amnesia and somnolence can result following recovery .