Very few reports pinpoint LSD as a cause of permanent health problems or death. That's not to say that there haven't been scary situations involving the drug. In 1974, The Western Journal of Medicine reported an instance in which eight people snorted multiple milligrams of LSD at a party thinking that the substance was cocaine.
Most of them passed out. In the hospital, they suffered from fevers, vomiting and internal bleeding. However, all of the patients recovered within 12 hours with no lasting effects. Five of them were examined regularly for a year afterwards for long-term problems.
For decades, LSD has been potentially linked to other health problems. There have been reports of heart attacks, strokes and other deaths associated with LSD use, but many of these users also had other recreational drugs in their systems, so the role of LSD was inconclusive.
The real physical damage associated with LSD comes from what can happen when someone loses inhibitions and has poor judgment, skewed perceptions or a sense of immortality while tripping. LSD users have accidentally killed themselves by walking in front of a car, falling from windows or buildings, or by making the mistake of driving while altered.
These people didn't "go crazy." LSD isn't likely to make someone go insane or become psychotic. It can interact with other drugs and cause psychotic symptoms (especially other drugs that work on neurotransmitters). Some people with histories of certain mental illnesses, such as schizophrenia or psychosis, may have their symptoms exacerbated on LSD. In susceptible subjects, it may also speed the onset of these illnesses.
Heavy LSD users can also develop profound social problems, completely ruin their sleep cycles, and lose interest in eating and personal hygiene. They become uninterested in participating in the world going on around them and feel completely disconnected from everybody else. The real problem is that because they're taking LSD so often, they think the LSD is creating the illusion that their life is a mess instead of recognizing that it really is a mess.
You won't typically hear about someone being in rehab for LSD abuse, because it's not perceived as an addictive drug. Using LSD for just a few days in a row can cause a person to build up a tolerance quickly, so it's rarely used more than once a week. A person who uses LSD twice a week is considered a heavy user. In addition, repeated trips tend to lose their novelty, and what once seemed magical becomes every day and commonplace. The effects caused by LSD aren't dependable in the way that other drugs' effects are -- you never know how you'll feel or what you'll see. That's why most addicts crave the dependable nature of drugs like heroin, cocaine, methamphetamine, and the like.
Next, let's take a look at LSD that's used for purposes other than recreation.