Bad trip
A bad trip is a frightening experience associated with use of a hallucinogenic drug such as LSD, salvinorin A, mescaline, or psilocybin. These experiences can range from something which is not present in the real world to a moment of extreme paranoia. The term is also used to describe people who have had panic attacks while using cannabis. Such effects are not seen as threatening or negative for some in the therapeutic community, and may have the potential to be highly beneficial to the user when properly resolved. They have been attributed to the inexperience or irresponsibility of the user, lack of proper preparation and environment for the trip, or unresolved psychological tensions triggered during the course of the experience.
It is suggested that, at a minimum, such crises be managed by preventing the individual from harming oneself or others by whatever means necessary up to and including physical restraint, providing him or her with a safe and comfortable space, and supervising him or her until all effects of the drug have completely worn off.

# Aspects
A multitude of reactions can occur during a psychedelic crisis. Users can experience many general senses of fear. Some users may be catapulted into a anxiety attack, a disabling reaction in which one is overcome with extreme fright. A user may be overwhelmed with the disconnection many psychedelics cause, and fear that they are going insane or will never return to reality. This can cause the user to fall into a profound depression. Other reactions include an amplification of nameless fears; that is, fears that are unfounded and are usually not encountered in normality.
Users may exhibit actions suggesting harm to themselves or others around them. This harm could take the form of suicidal ideation, or full blown suicide attempts. Because of the magnification of emotions many psychedelics cause, death or thoughts of death can cause intensely adverse reactions in some users. Users can believe that their death is imminent or that the very universe itself is collapsing. Rapidly accelerated aging of other people may be experienced, irritating the aforementioned fears even more.
Some users may experience disorientation. The normal views of time, space, and person can be substantially altered, causing fear. Some can worsen their condition by trying to fight the psychedelic experience after embarkment. There can be illusions of insects crawling over or into one's self, or of being in dirty places such as sewers.

## Unpredictability of the experience
The effects of psychedelic drugs vary widely from one individual to the next, and from one experience to the next. Sometimes individuals under the influence of such drugs forget that they have taken them, and believe that the wildly distorted world they perceive is real and will be with them indefinitely. In cases where the individual cannot be kept safe, hospitalization may be useful, though the value of this practice for individuals not mentally ill is disputed by proponents of investigative or recreational use of psychoactive compounds. Psychosis is exacerbated in individuals already suffering from this condition.

# Intervention
Generally, a person experiencing a psychedelic crisis can be helped to either resolve the impasse, bypass it, or, failing that, to terminate the experience.

## Psychologically
In the event of a psychedelic crisis, one possible intervention is a well lit space.  Darkness enhances the inner experience.  A change of environment can immediately calm the person, as new stimulus automatically generates new and different experiences.  It's helpful to have around a trusted friend (who, ideally, has taken or is educated on the drug(s)-in-action) that can support or "talk down" the individual going through a deep, difficult period of a drug experience. This "trip-sitter" must first get a feel for how distorted or disconnected the tripper feels; it's important for the sitter not to react to these exclamations/lamentations in a way that might make the tripper feel more disconnected, i.e. "Whoa, you must be really high," "You have to calm down," etc. This will only create a sense of urgency. Remind the distressed individual that the emotions and physical sensations they are experiencing are almost certainly just an effect of the drug, they are normal and will eventually pass. It should be noted here that with hallucinogens in particular, the mental high is undulating and dynamic; the intensity is likely just a part of the first few waves, it will not last for the duration of the trip. And so it may be helpful to remind them of the passing time (a bad trip can make time feel intensely dilated, if not destroyed) and to show them how everything around them is okay; there is nothing to panic over and the turbulence is only in their mind. It is also very important to talk calmly to the individual and not become agitated by their behavior, as this will only amplify the most negative aspects of whatever their mind is processing during the bad trip. An experienced or even unexperienced recreational drug user can also "talk" himself down using CBT (Cognitive Behavioural Therapy), slow breathing and thinking techniques, it is, however recommended that the individual does have someone he trusts to help him or her through.

## Medically
Medical treatment consists of supportive therapy and minimization of external stimuli. In some cases, sedation is used when necessary to control self-destructive behavior, or when hyperthermia occurs. Valium is the most frequently used sedative for such treatment, but other benzodiazepines such as Ativan are also effective.  Such sedatives will only decrease fear and anxiety, but will not subdue hallucinations. In severe cases, antipsychotics such as haloperidol can reduce or stop hallucinations, but this treatment is only effective against the so-called "classical" hallucinogens (LSD, psilocybin and mescaline, among others). Antipsychotics are not effective against dissociatives such as PCP and ketamine, and should not be used if these drugs are involved. According to Timothy Leary, a simple temporary fix to a bad trip is sugar (in the form of candy, oranges, etc.), since crises may often be the result of people forgetting to eat and experiencing hyperawareness of low blood sugar.

# Potential Causes
According to Timothy Leary, a crisis can be a result of wrong set and setting.  Leary advised that users of psychedelics be sure that they are comfortable before taking the drugs. Leary claimed that the frequency of difficult trips was highly exaggerated by anecdotes and fabrications in the popular press, and was actually about 1 in 1000.
Alternatively, psychologist R. D. Laing held that psychedelic crises and other such extreme experiences, drug-induced or not, were not necessarily artificial terrors to be suppressed but rather signs of internal conflict and opportunities for self-healing. The greater the pain and pathos of an experience, the greater the urgency to explore and resolve it, rather than attempt to cover it up or dismiss it.
Likewise, Stanislav Grof suggested that painful and difficult experiences during a trip could be a result of the mind reliving experiences associated with birth, and that experiences of imprisonment, eschatological terror, or suffering far beyond anything imaginable in a normal state, if seen through to conclusion, often resolve into emotional, intellectual and spiritual breakthroughs. From this perspective, interrupting a bad trip, while initially seen as beneficial, can trap the tripper in unresolved psychological states.  Grof also suggests that many cathartic experiences within psychedelic states, while not necessarily crises, may be the effects of consciousness entering a perinatal space.

# Effects of cannabis
Though cannabis can lead to panic states in some cases, it does not usually cause "bad trips" when used by itself in moderate dosages. It can however cause anxiety or panic attacks at moderate dosages. Because cannabis can induce anxiety attacks, it could trigger a psychedelic crisis in a user already under the influence of a hallucinogen especially at a difficult moment. It is likely to exacerbate confusion, panic and paranoia.
At very high dosages, cannabis is itself hallucinogenic and it is likely that it can cause psychedelic crises directly comparable to those caused by other hallucinogens. As is the case with other hallucinogenic drugs, this effect has not been studied and proven clinically.
In some cases, however, cannabis can calm someone under a hallucinogenic trip, and somewhat put the trip on "hold" until they are calm enough to allow themselves to continue on.