Generally, a person experiencing a psychedelic crisis can be helped either to resolve the impasse, to bypass it, or, failing that, to terminate the experience. A person's thoughts before taking or while under the influence of the psychedelic, often greatly influence the trip.

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. Diazepam is the most frequently used sedative for such treatment, but other benzodiazepines such as lorazepam 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. Haloperidol is effective against drug-induced psychosis caused by LSD and other tryptamines, amphetamines, ketamine and phencyclidine.

Definitive diagnosis relies on a blood test for alcohol, usually performed as part of a toxicology screen.

Law enforcement officers in the United States of America often use breathalyzer units and field sobriety tests as more convenient and rapid alternatives to blood tests.

There are also various models of breathalyzer units that are available for consumer use. Because these may have varying reliability and may produce different results than the tests used for law-enforcement purposes, the results from such devices should be conservatively interpreted.

Many informal intoxication tests exist, which, in general, are unreliable and not recommended as deterrents to excessive intoxication or as indicators of the safety of activities such as motor vehicle driving, heavy equipment operation, machine tool use, etc.

For determining whether someone is intoxicated by alcohol by some means other than a blood-alcohol test, it is necessary to rule out other conditions such as hypoglycemia, stroke, usage of other intoxicants, mental health issues, and so on. It is best if his/her behavior has been observed while the subject is sober to establish a baseline. Several well-known criteria can be used to establish a probable diagnosis. For a physician in the acute-treatment setting, acute alcohol intoxication can mimic other acute neurological disorders, or is frequently combined with other recreational drugs that complicate diagnosis and treatment.

A bad trip (drug-induced temporary psychosis or psychedelic crisis) is a disturbing experience typically associated with use of one or more of various hallucinogens of types including psychedelics, such as LSD, mescaline, psilocybin, and DMT, dissociatives, such as dextromethorphan, and phencyclidine, and deliriants, such as Salvinorin A (the active chemical of "Salvia divinorum").

The manifestations can range from feelings of vague anxiety and alienation to profoundly disturbing states of unrelieved terror, ultimate entrapment, or complete loss of self-identity. Psychedelic specialists in the therapeutic community do not necessarily consider unpleasant experiences as threatening or negative, instead focusing on their potential to greatly benefit the user when properly resolved. Bad trips can be exacerbated by the inexperience or irresponsibility of the user or the lack of proper preparation and environment for the trip, and are reflective of 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 the patient with a safe and comfortable space, and supervising the intake until all effects of the drug have completely worn off.

Hangovers are poorly understood from a medical point of view. Health care professionals prefer to study alcohol abuse from a standpoint of treatment and prevention, and there is a view that the hangover provides a useful, natural and intrinsic disincentive to excessive drinking.

Within the limited amount of serious study on the subject, there is debate about whether a hangover may be prevented or at least mitigated. There is also a vast body of folk medicine and simple quackery. A four-page literature review in the "British Medical Journal" concludes: "No compelling evidence exists to suggest that any conventional or complementary intervention is effective for preventing or treating alcohol hangover. The most effective way to avoid the symptoms of alcohol induced hangover is to avoid drinking." Most remedies do not significantly reduce overall hangover severity. Some compounds reduce specific symptoms such as vomiting and headache, but are not effective in reducing other common hangover symptoms such as drowsiness and fatigue

There is no evidence that any treatment for hangovers is very effective.

- Rehydration: Drinking water before going to bed or during hangover may relieve dehydration-associated symptoms such as thirst, dizziness, dry mouth, and headache.

- Non-steroidal anti-inflammatory drugs such as aspirin or ibuprofen have been proposed as a treatment for the headaches associated with a hangover. There however is no evidence to support a benefit, and there are concerns that taking alcohol and aspirin together may increase the risk of stomach bleeding and liver damage.

- Tolfenamic acid, an inhibitor of prostaglandin synthesis, in a 1983 study reduced headache, nausea, vomiting, irritation but had no effect on tiredness in 30 people.

- Pyritinol: A 1973 study found that large doses (several hundred times the recommended daily intake) of Pyritinol, a synthetic Vitamin B6 analog, can help to reduce hangover symptoms. Possible side effects of pyritinol include hepatitis (liver damage) due to cholestasis and acute pancreatitis.

- Yeast-based extracts: The difference in the change for discomfort, restlessness, and impatience were statistically significant but no significant differences on blood chemistry parameters, blood alcohol or acetaldehyde concentrations have been found, and it did not significantly improve general well-being.

Acute alcohol poisoning is a medical emergency due to the risk of death from respiratory depression and/or inhalation of vomit if emesis occurs while the patient is unconscious and unresponsive. Emergency treatment for acute alcohol poisoning strives to stabilize the patient and maintain a patent airway and respiration, while waiting for the alcohol to metabolize. This can be done by removal of any vomitus or, if patient is unconscious or has impaired gag reflex, intubation of the trachea using an endotracheal tube to maintain adequate airway:

Also:

- Treat hypoglycaemia (low blood sugar) with 50 ml of 50% dextrose solution and saline flush, as ethanol induced hypoglycaemia is unresponsive to glucagon.

- Administer the vitamin thiamine to prevent Wernicke-Korsakoff syndrome, which can cause a seizure (more usually a treatment for chronic alcoholism, but in the acute context usually co-administered to ensure maximal benefit).

- Apply hemodialysis if the blood concentration is dangerously high (>400 mg/dL), and especially if there is metabolic acidosis.

- Provide oxygen therapy as needed via nasal cannula or non-rebreather mask.

- Provide parenteral Metadoxine.

Additional medication may be indicated for treatment of nausea, tremor, and anxiety.

Pregaming (also pre-drinking or pre-loading) is the process of getting drunk prior to going out socializing, typically done by college students and young adults in the United States and Europe, in a manner as cost-efficient as possible, with hard liquor and cheap beer consumed while in small groups.

Although pregaming is typically done before a night out, it can also precede other activities, like attending a college football game, large party, social function, or another activity where possession of alcohol may be limited or prohibited. The name "pregaming" spread from the drinking that took place during tailgating before football games to encompass similar drinking periods.

Other terms for the practice are pre-partying, prinking and (in Europe) prefunking.

Pregaming has been associated with binge drinking and other dangerous activities, leading some universities to attempt to crack down on the practice. Government agencies at both the state and federal level have studied the problems created by pregaming.

The furtive nature of pregaming and bingeing can lead to massive quick consumption, acute alcohol poisoning, hospitalization, and death.

A 2012 study of more 250 Swiss students indicated that those who "pre-loaded" ended up consuming more total alcohol over the night (seven drinks rather than four) and engaged in riskier behavior. They had a 24% chance of reporting negative consequences from drinking (such as injury, unprotected sex, and unplanned drug use), compared to 18% chance for those who did not pre-drink.

Alcohol dependence is not prerequisite to blackouts (either en bloc or fragmentary). Students in one study who reported blackouts were demographically similar to other drinking students. Importantly, however, students reporting blackouts drank more, and had other symptoms of alcoholic drinking, even though they did not fall into the alcoholic range on the Michigan Alcoholism Screening Test (MAST). Half of the students reported having had a blackout during their drinking careers, which closely followed other research findings.

In another study 25% of healthy college students reported being familiar with alcoholic blackouts. 51% of the students reported that they had had at least one blackout. Blackouts were reported during activities such as spending money (27%), sexual conduct (24%), fighting (16%), vandalism (16%), unprotected intercourse (6%), and driving a car (3%). So a significant number of students were engaged in a range of possibly hazardous activities during blackouts.

Of 545 individuals in another study, 161 (29.5%) reported driving drunk, 139 (25.5%) reported a regretted sexual situation, 67 (12.3%) reported unprotected sex, 60 (11%) reported having damaged property, 55 (10.1%) reported getting into a physical fight, and 29 (5.3%) reported injuring someone while under the influence of alcohol in the past 6 months.

Other medical conditions that can resemble excited delirium are panic attack, hyperthermia, diabetes, head injury, delirium tremens, and hyperthyroidism.

Treatment initially may include ketamine or midazolam and haloperidol injected into a muscle to sedate the person. Rapid cooling may be required in those with high body temperature. Other supportive measures such as intravenous fluids and sodium bicarbonate may be useful.

There are several different screening tools that have been validated for use with adolescents such as the CRAFFT Screening Test and in adults the CAGE questionnaire.

Some recommendations for screening tools for substance misuse in pregnancy include that they take less than 10 minutes, should be used routinely, include an educational component. Tools suitable for pregnant women include i.a. 4Ps, T-ACE, TWEAK, TQDH (Ten-Question Drinking History), and AUDIT.

Multiple guidelines recommend that delirium should be diagnosed when it presents to healthcare services. Much evidence suggest, however, that delirium is greatly underdiagnosed. Higher rates of detection of delirium in general settings (for the ICU see below) can be assisted by the use of validated delirium screening tools. Many such tools have been published. They differ in duration, complexity, need for training, and so on. Examples of tools in use in clinical practice are: Delirium Observation Screening Scale, the Nursing Delirium Screening Scale (Nu-DESC), the Confusion Assessment Method, the Recognizing Acute Delirium As part of your Routine (RADAR) tool and the 4 "A"s Test or 4AT.

Ideas of reference and delusions of reference describe the phenomenon of an individual's experiencing innocuous events or mere coincidences and believing they have strong personal significance. It is "the notion that everything one perceives in the world relates to one's own destiny".

In psychiatry, delusions of reference form part of the diagnostic criteria for psychotic illnesses such as schizophrenia, delusional disorder, bipolar disorder (during the elevated stages of mania), as well as schizotypal personality disorder. To a lesser extent, it can be a hallmark of paranoid personality disorder. Such symptoms can also be caused by intoxication, especially with hallucinogens or stimulants like methamphetamine.

In the ICU, international guidelines recommend that every patient gets checked for delirium every day (usually twice or more a day) using a validated clinical tool. The two most widely used are the Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC). There are translations of these tools in over 20 languages and they are used globally in many thousands of ICUs, and instructional videos and myriad implementation tips are available. It is not as important which tool is used as that the patient gets monitored. Without using one of these tools, 75% of ICU delirium is missed by the practicing team, which leaves the patient without any likely active interventions to help reduce the duration of his/her delirium.

The most salient component of the definition of delirium that nurses and other healthcare professionals use at the bedside is whether or not the patient can pay attention and follow simple commands (see videos and literature). The advent of daily monitoring for delirium, made easy by the CAM-ICU and other assessment tools, as well as proper documentation, had led to important changes in the culture of ICUs and rounds in that the entire team can now discuss the brain and how it is doing in terms of being “on” (not delirious) or “off” (delirious) and then focus on the several most likely causes of delirium in any specific patient. Thus, it is not the monitoring itself that changes the patient’s clinical course, but rather it is this combination of monitoring and then relaying the information on rounds in the ICU that makes such a huge difference in awareness of this form of organ dysfunction and then enables a difference to be made in clinical outcomes.

In general, the simultaneous use of multiple drugs should be carefully monitored by a qualified individual such as board certified and licensed medical doctor, either an MD or DO Close association between prescribing physicians and pharmacies, along with the computerization of prescriptions and patients' medical histories, aim to avoid the occurrence of dangerous drug interactions. Lists of contraindications for a drug are usually provided with it, either in monographs, package inserts (accompanying prescribed medications), or in warning labels (for OTC drugs). CDI/MDI might also be avoided by physicians requiring their patients to return any unused prescriptions. Patients should ask their doctors and pharmacists if there are any interactions between the drugs they are taking.

People who engage in polypharmacy and other hypochondriac behaviors are at an elevated risk of death from CDI. Elderly people are at the highest risk of CDI, because of having many age-related health problems requiring many medications combined with age-impaired judgment, leading to confusion in taking medications.

Some medical systems, including those of at least 15 states of the United States, refer to an Addiction Severity Index to assess the severity of problems related to substance use. According to DARA Thailand, the index assesses potential problems in seven categories: medical, employment/support, alcohol, other drug use, legal, family/social, and psychiatric.

Substance use disorders can be confused with other psychiatric disorders. There are diagnoses for substance-induced mood disorders and substance-induced anxiety disorders and thus such overlap can be complicated. For this reason, the DSM-IV advises that diagnoses of primary psychiatric disorders not be made in the absence of sobriety (of duration sufficient to allow for any substance-induced post-acute-withdrawal symptoms to dissipate) up to 1 year.

Questionnaires and checklists such as the Beck Depression Inventory or the Children's Depression Inventory can be used by a mental health provider to help detect, and assess the severity of depression. The Seasonal Pattern Assessment Questionnaire can be used to screen for seasonal affective disorder. Semi structured interviews such as the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS) and the Structured Clinical Interview for DSM-IV (SCID) are used for diagnostic confirmation of depression.

The substance that has been taken may often be determined by asking the person. However, if they will not, or cannot, due to an altered level of consciousness, provide this information, a search of the home or questioning of friends and family may be helpful.

Examination for toxidromes, drug testing, or laboratory test may be helpful. Other laboratory test such as glucose, urea and electrolytes, paracetamol levels and salicylate levels are typically done. Negative drug-drug interactions have sometimes been misdiagnosed as an acute drug overdose, occasionally leading to the assumption of suicide.

Blackouts are commonly associated with the consumption of large amounts of alcohol; however, surveys of drinkers experiencing blackouts have indicated that they are not directly related to the amount of alcohol consumed. Respondents reported they frequently recalled having "drunk as much or more without memory loss," compared to instances of blacking out. Subsequent research has indicated that blackouts are most likely caused by a rapid increase in a person's blood-alcohol concentration. One study, in particular, resulted in subjects being stratified easily into two groups, those who consumed alcohol very quickly, and blacked out, and those who did not black out by drinking alcohol slowly, despite being extremely intoxicated by the end of the study.

In another study hospital file data showed, that of 67 participants, 39 had reported a blackout. The presence or absence of blackouts was cross-tabulated against various measures of alcohol problem severity. The presence of blackouts was associated to some degree with some indications of severity such as withdrawal and loss of control, but not with duration of problem drinking, physical complications or abnormal liver function.

The presence of blackouts was related to some measures of severity of the problem – withdrawal symptoms and loss of control. The hypotheses that blackouts either reflect a general vulnerability to the cerebral consequences of alcohol abuse or are associated with other forms of more enduring cognitive impairment did not receive any support.

In another study which looked at subjective responses to alcohol as a prime for 21st birthday alcohol consumption, subjective responses to the initial drink were viewed as a prime for more alcohol consumption during 21st birthday celebrations. Current findings show that subjective responses to alcohol have direct effects on both the final BAC achieved and on the experiences of blackouts and hangover that are not explained by level of intoxication. Where a variety of social factors, such as peer pressure and 21st birthday traditions such as 21 shots may influence the amount of alcohol people consume, their subjective experiences with alcohol have clear influences on both consumption and the physiological consequences of drinking. These physiological responses to alcohol may have a biological vulnerability that extends beyond the dose-dependent effects of alcohol.

Self reports from another study showed that 63% of patients in the study gulped their drinks rather than sipped. Five patients recollected vomiting during the drinking episode while 32 drank on an empty stomach and 41 drank more than originally planned. During the drinking episode 31% subjects described blackouts, 20% described brownouts, and 49% reported no amnesic episode.

It is common for individuals with drugs use disorder to have other psychological problems. The terms “dual diagnosis” or “co-occurring disorders,” refer to having a mental health and substance use disorder at the same time. According to the British Association for Psychopharmacology (BAP), “symptoms of psychiatric disorders such as depression, anxiety and psychosis are the rule rather than the exception in patients misusing drugs and/or alcohol.”

Individuals who have a comorbid psychological disorder often have a poor prognosis if either disorder is untreated. Historically most individuals with dual diagnosis either received treatment only for one of their disorders or they didn’t receive any treatment all. However, since the 1980s, there has been a push towards integrating mental health and addiction treatment. In this method, neither condition is considered primary and both are treated simultaneously by the same provider.

Psychosis is first and foremost a diagnosis of exclusion. So a new-onset episode of psychosis "cannot" be considered a symptom of a psychiatric disorder until other relevant and known causes of psychosis are properly excluded, or ruled out. Many clinicians improperly perform, or entirely miss this step, introducing avoidable diagnostic error and misdiagnosis.

An initial assessment includes a comprehensive history and physical examination by a physician, psychiatrist, psychiatric nurse practitioner or psychiatric physician assistant. Biological tests should be performed to exclude psychosis associated with or caused by substance use, medication, toxins, surgical complications, or other medical illnesses.

Delirium should be ruled out, which can be distinguished by visual hallucinations, acute onset and fluctuating level of consciousness, indicating other underlying factors, including medical illnesses. Excluding medical illnesses associated with psychosis is performed by using blood tests to measure:

- Thyroid-stimulating hormone to exclude hypo- or hyperthyroidism,

- Basic electrolytes and serum calcium to rule out a metabolic disturbance,

- Full blood count including ESR to rule out a systemic infection or chronic disease, and

- Serology to exclude syphilis or HIV infection.

Other investigations include:

- EEG to exclude epilepsy, and an

- MRI or CT scan of the head to exclude brain lesions.

Because psychosis may be precipitated or exacerbated by common classes of medications, medication-induced psychosis should be ruled out, particularly for first-episode psychosis. Both substance- and medication-induced psychosis can be excluded to a high level of certainty, using a

- Urinalysis and a

- Full serum toxicology screening.

Because some dietary supplements may also induce psychosis or mania, but cannot be ruled out with laboratory tests, a psychotic individual's family, partner, or friends should be asked whether the patient is currently taking any dietary supplements.

Common mistakes made when diagnosing people who are psychotic include:

- Not properly excluding delirium,

- Not appreciating medical abnormalities (e.g., vital signs),

- Not obtaining a medical history and family history,

- Indiscriminate screening without an organizing framework,

- Missing a toxic psychosis by not screening for substances "and" medications

- Not asking family or others about dietary supplements,

- Premature diagnostic closure, and

- Not revisiting or questioning the initial diagnostic impression of primary psychiatric disorder.

Only after relevant and known causes of psychosis are excluded, a mental health clinician may make a psychiatric differential diagnosis using a person's family history, incorporating information from the person with psychosis, and information from family, friends, or significant others.

Types of psychosis in psychiatric disorders may be established by formal rating scales. The Brief Psychiatric Rating Scale (BPRS) assesses the level of 18 symptom constructs of psychosis such as hostility, suspicion, hallucination, and grandiosity. It is based on the clinician's interview with the patient and observations of the patient's behavior over the previous 2–3 days. The patient's family can also answer questions on the behavior report. During the initial assessment and the follow-up, both positive and negative symptoms of psychosis can be assessed using the 30 item Positive and Negative Symptom Scale (PANSS).

Although exact rates of prevalence are not available, general population data shows a 0.002% prevalence over a year-long period and higher prevalence within clinical populations.