I do not know of this personally -- since I consider my mind too fragile to try hallucinogens, even at Caltech in the late '70s -- but I have heard anecdotes of people experiencing terrible, sometimes multiday, bad trips with jimson weed or the West European "witch" alkaloids (i.e., belladonna, hellebore, henbane).
In all of these cases, the person seems to never be able to have a hallucination again. The prospect of taking acid becomes unthinkably frightening, and even using marijuana can become so anxiety ridden as to be impractical. Is this true?
You've asked about a group of plants -- jimson weed (thorn apple), mandrake, henbane and deadly nightshade -- that have fascinated humans for at least 3,500 years. The ancient Egyptians and Greeks wrote about their various uses as poisons, medicines and hallucinogens. They were also popular with magicians and healers through the Middle Ages and with Native American tribes of North America. The active chemicals have been refined into modern medicines that are used to treat asthma and motion sickness, though some people still smoke or drink plant extracts for their intense hallucinatory properties.
In all of these plants, atropine and scopolamine are the active ingredients. These chemicals block the action of the neurochemical acetylcholine. A person who consumes one of these plants usually experiences a high heart rate, dry mouth, an elevated body temperature and dilated pupils and has difficulty urinating -- all of the things that acetylcholine controls. It's the dilated pupils that gave rise to the name "belladonna alkaloids" because women in the Middle Ages used them to enhance their appearance (hence belladonnna, or beautiful woman). These effects are profound and can be deadly, which is why they were popular poisons in the Middle Ages.
These chemicals can easily enter the body through the skin, so simply rubbing parts of the plants on a person can induce profound physical changes as well as an alteration of consciousness. No matter how the plant is taken, an additional mystical property is amnesia. Scopolamine easily enters the brain and blocks brain acetylcholine sensors, which prevents the nerve cells from recording new information. Thus a user might recall some very unpleasant physical effects that preceded and followed the hallucinations, but not so much about the actual experience itself. At the highest doses, these drugs can induce a state in which a person feels separated from himself or herself, resulting in a floating and flying sensation (one of the reasons they are called "witch" alkaloids).
There is no safe way to use these chemicals as mind-altering drugs. By the time a person is hallucinating, the drug is already affecting many of the body's functions. The trancelike state that leads to hallucinations happens only after body temperature and heart rate are already at dangerous levels. When the brain senses the strong cardiovascular stimulation, it interprets these conditions as a very fearful experience and it remembers it very well. Thus any subsequent use of a mind-altering chemical may cue the brain to expect another of these hellish trips and trigger fear.
In an overdose situation, a user can have seizures or lapse into a coma. There are specific and effective treatments for atropine and scopolamine poisoning, but treating physicians first must know what is wrong. These events are so rare that they might be misdiagnosed, and a delay in treatment can result in brain damage or death. Our advice is to leave the use of these plants to the past.
Buzzed appears every Wednesday in Salon Health. Do you have a question on any type of drug -- pharmaceutical or illegal? Send it to us at firstname.lastname@example.org.