Methamphetamine in the context of Attention deficit hyperactivity disorder

Smoking is a human behavior which involves the combustion of a substance, usually plant material, and the inhalation of resulting fumes. Today smoking is mostly practiced by rolling the dried leaves of the tobacco plant into a cigarette. Other forms of tobacco smoking include the use of a smoking tobacco with a pipe or cigar, or using a bong. Cigarette smokers almost always inhale the smoke; most pipe and cigar smokers do not inhale.

Smoking is primarily practiced as a route of administration for psychoactive chemicals because the active substances within the burnt, dried plant leaves (or other chemical) can vaporize into a gaseous state and be delivered into the respiratory tract, where they are rapidly absorbed into the bloodstream through the lungs and can reach the central nervous system. In the case of tobacco smoking, these active substances are a mixture of aerosol particles that include the pharmacologically active alkaloid nicotine, which stimulates the nicotinic acetylcholine receptors in the brain, and other non-psychoactive chemicals that result from combustion. Other notable drugs inhaled via smoking include tetrahydrocannabinol (from cannabis), morphine (from opium) cocaine (from crack), and methamphetamine. Designer drugs, or "research chemicals", can also be smoked.

Recreational drug use is the use of one or more psychoactive drugs to induce an altered state of consciousness, either for pleasure or for some other casual purpose or pastime. When a psychoactive drug enters the user's body, it induces an intoxicating effect. Recreational drugs are commonly divided into three categories: depressants (drugs that induce a feeling of relaxation and calmness), stimulants (drugs that induce a sense of energy and alertness), and hallucinogens (drugs that induce perceptual distortions such as hallucination).

In popular practice, recreational drug use is generally tolerated as a social behaviour, rather than perceived as the medical condition of self-medication. However, drug use and drug addiction are severely stigmatized everywhere in the world. Many people also use prescribed and controlled depressants such as opioids, opiates, and benzodiazepines. What controlled substances are considered generally unlawful to possess varies by country, but usually includes cannabis (though some areas have legalised cannabis use), cocaine, opioids, MDMA, amphetamine, methamphetamine, psychedelics, benzodiazepines, and barbiturates. As of 2015, it is estimated that about 5% of people worldwide aged 15 to 65 (158 million to 351 million) had used controlled drugs at least once.

3,4-Methylenedioxymethamphetamine (MDMA), commonly known as ecstasy (tablet form), and molly (crystal form), is an entactogen with stimulant and minor psychedelic properties.

MDMA was first synthesized in 1912 by Merck chemist Anton Köllisch. It was used to enhance psychotherapy beginning in the 1970s and became popular as a street drug in the 1980s. MDMA is commonly associated with dance parties, raves, and electronic dance music. Tablets sold as ecstasy may be mixed with other substances such as ephedrine, amphetamine, and methamphetamine. In 2016, about 21 million people between the ages of 15 and 64 used ecstasy (0.3% of the world population). In the United States, as of 2017, about 7% of people have used MDMA at some point in their lives and 0.9% have used it in the last year. The lethal risk from one dose of MDMA is estimated to be from 1 death in 20,000 instances to 1 death in 50,000 instances.

A drug test (also often toxicology screen or tox screen) is a technical analysis of a biological specimen, for example urine, hair, blood, breath, sweat, or oral fluid/saliva—to determine the presence or absence of specified parent drugs or their metabolites. Major applications of drug testing include detection of the presence of performance enhancing steroids in sport, employers and parole/probation officers screening for drugs prohibited by law (such as cocaine, methamphetamine, and heroin) and police officers testing for the presence and concentration of alcohol (ethanol) in the blood commonly referred to as BAC (blood alcohol content). BAC tests are typically administered via a breathalyzer while urinalysis is used for the vast majority of drug testing in sports and the workplace. Numerous other methods with varying degrees of accuracy, sensitivity (detection threshold/cutoff), and detection periods exist.

A drug test may also refer to a test that provides quantitative chemical analysis of an illegal drug, typically intended to help with responsible drug use.

Stimulants (also known as central nervous system stimulants, or psychostimulants, or colloquially as uppers) are a class of psychoactive drugs that increase alertness. They are used for various purposes, such as enhancing attention, motivation, cognition, mood, and physical performance. Some stimulants occur naturally, while others are exclusively synthetic. Common stimulants include caffeine, nicotine, cocaine (including crack cocaine), amphetamine/methamphetamine, methylphenidate, and modafinil. Stimulants may be subject to varying forms of regulation, or outright prohibition, depending on jurisdiction. Most stimulants are highly addictive and damage health when addicted.

Stimulants increase activity in the sympathetic nervous system, either directly or indirectly. Prototypical stimulants increase synaptic concentrations of excitatory neurotransmitters, particularly norepinephrine and dopamine (e.g., methylphenidate). Other stimulants work by binding to the receptors of excitatory neurotransmitters (e.g., nicotine) or by blocking the activity of endogenous agents that promote sleep (e.g., caffeine). Stimulants can affect various functions, including arousal, attention, the reward system, learning, memory, and emotion. Effects range from mild stimulation to euphoria, depending on the specific drug, dose, route of administration, and inter-individual characteristics.

Ideas of reference and delusions of reference describe the phenomenon of an individual 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", usually in a negative and hostile manner.

In psychiatry, delusions of reference form part of the diagnostic criteria for psychotic illnesses such as schizophrenia, delusional disorder, schizoaffective disorder and bipolar disorder with mania, as well as for schizotypal personality disorder. To a lesser extent, their presence can be a hallmark of paranoid personality disorder, as well as body dysmorphic disorder. They can be found in autism during periods of intense stress. They can also be caused by intoxication, such as from stimulants like methamphetamine. Psychedelics like psilocybin have also been reported to produce ideas of reference during experiences.

An aphrodisiac is a substance that increases libido, sexual desire, sexual attraction, sexual pleasure, or sexual behavior. These substances range from a variety of plants, spices, and foods to synthetic chemicals. Natural aphrodisiacs, such as cannabis or cocaine, are classified into plant-based and non-plant-based substances. Synthetic aphrodisiacs include MDMA and methamphetamine. Aphrodisiacs can be classified by their type of effects (psychological or physiological). Aphrodisiacs that contain hallucinogenic properties, such as bufotenin, have psychological effects that can increase sexual desire and sexual pleasure. Aphrodisiacs that have smooth muscle relaxing properties, such as yohimbine, have physiological effects that can affect hormone concentrations and increase blood flow. Substances that have the opposite effects on libido are called anaphrodisiacs. Aphrodisiac effects can also be due to the placebo effect.

Both males and females can potentially benefit from the use of aphrodisiacs, but they are more focused on males, as their properties tend to increase testosterone concentrations rather than estrogen concentrations. This is in part due to the historical context of aphrodisiacs, which focused solely on males. Only recently has attention been paid to understanding how aphrodisiacs can aid female sexual function. In addition, cultural influences on appropriate sexual behavior of males and females also play a part in the research gap.

Crime is one of the most urgent concerns facing Mexico, as Mexican drug trafficking rings play a major role in the flow of cocaine, methamphetamine, fentanyl, heroin, and marijuana transiting between Latin America and the United States. Drug trafficking has led to corruption, which has had a deleterious effect on Mexico's Federal Representative Republic. Drug trafficking and organized crime have been a major source of violent crime. Drug cartels and gangs have also branched out to conduct alternative illegal activities for profit, including sex trafficking. Some of the most increasingly violent states in Mexico in 2020 included Guanajuato, Zacatecas, Michoacán, Jalisco, and Querétaro. Some of the world's most violent cities are reportedly within the state of Guanajuato with extortion from criminal groups (such as CSRL and CJNG) now being commonplace. The state of Zacatecas is said to be valuable to multiple organized crime groups (including the Sinaloa Cartel and CJNG) for drug trafficking, specifically methamphetamine to the United States. As of 2021, Michoacán is experiencing increased instances of extortion and kidnapping due to a growing presence and escalation in the armed conflicts between CJNG and Cárteles Unidos on regions bordering the neighboring state of Jalisco. CJNG is also currently battling the Los Chapitos faction of the Sinaloa Cartel in the North Mexican region of Sonora.

Mexico has experienced increasingly high crime rates, especially in major urban centers. The country's great economic polarization has stimulated criminal activity mainly in the lower socioeconomic strata, which include the majority of the country's population. Crime is increasing at high levels, and is repeatedly marked by violence, especially in the cities of Tijuana and Ciudad Juárez, and the states of Baja California, Durango, Sinaloa, Guerrero, Chihuahua, Michoacán, Tamaulipas, and Nuevo León. Other metropolitan areas have lower, yet still serious, levels of crime. Low apprehension and conviction rates contribute to the high crime rate. Since many crimes go unreported, the rates may be much higher than reported by the government. The murder rate in 2023 was 23.3 per 100,000. Most of the crime is committed by a small proportion of the population involved in the drug trade with about half of murders being drug-related.

Substituted amphetamines, or simply amphetamines, are a class of compounds based upon the amphetamine structure; it includes all derivative compounds which are formed by replacing, or substituting, one or more hydrogen atoms in the amphetamine core structure with substituents. The compounds in this class span a variety of pharmacological subclasses, including stimulants, empathogens, and hallucinogens, among others. Examples of substituted amphetamines are amphetamine (itself), methamphetamine, ephedrine, cathinone, phentermine, mephentermine, tranylcypromine, bupropion, methoxyphenamine, selegiline, amfepramone (diethylpropion), pyrovalerone, MDMA (ecstasy), and DOM (STP).

Some of amphetamine's substituted derivatives occur in nature, for example in the leaves of Ephedra and khat plants. Amphetamine was first produced at the end of the 19th century. By the 1930s, amphetamine and some of its derivative compounds found use as decongestants in the symptomatic treatment of colds and also occasionally as psychoactive agents. Their effects on the central nervous system are diverse, but can be summarized by three overlapping types of activity: stimulant, psychedelic, and entactogenic. Various substituted amphetamines may cause these actions either separately or in combination.