Volatile substances are chemical compounds that give off fumes at room temperature . They are also called ‘inhalants’ in recognition of their route of administration. Volatile substance use (VSU) is the ‘practice of deliberately inhaling (“sniffing”, “huffing”, “bagging” or “chroming”) substances that are vaporous at ambient temperatures for the purpose of becoming intoxicated’ (, p.23).
Volatile substances are central nervous system depressants which produce an immediate and intense intoxication for users. The onset of effect occurs rapidly because the extensive capillary surface of the lungs readily absorbs the vapour, causing blood levels to peak within minutes of use .
There are approximately 250 household, medical and industrial products that contain potentially intoxicating volatile substances . Many of these are readily available and inexpensive.
Volatile substances are usually classified into four groups :
While the chemicals used in VSU are diverse, as is the broad range of effects, the main characteristic linking all of these substances is that they are almost exclusively inhaled . Inhaling methods include:
The psychoactive effects of inhaling volatile substances occur rapidly but only last for a short time (5 to 45 minutes after ceasing use) . However, the fat soluble nature of volatile substances means that they can be stored in neurological tissues and have a prolonged effect on the level of consciousness for a much longer time period.
Many of the harmful physical effects from VSU are reversible, especially for infrequent users . The damage caused by VSU is cumulative; chronic VSU is associated with an increased likelihood of permanent brain injury , although the extent of VSU-caused brain injury is debated in the literature .
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Some inhalants can indirectly cause sudden death by cardiac arrest in a syndrome known as ‘sudden sniffing death’ . The hydrocarbon gases present in the inhalants appear to sensitise the myocardium to adrenaline. In this state, a sudden surge of adrenaline (for example, from a frightening hallucination or intense physical activity) can cause a fatal cardiac arrhythmia. Sudden sniffing death can occur after a single use and is associated with the inhalation of butane, propane, and the chemicals found in aerosols .
Individuals who inhale petrol can die as a result of asphyxiation. The oxygen in the lungs is displaced by the inhaled petrol vapour which may stop the user from breathing . Inhaling petrol from a bag or in a confined space (such as under a blanket) increases the risk of death from asphyxiation. The risk of death from asphyxiation also applies to Opal fuel . Spraying volatile substances directly into the mouth is thought to cause asphyxiation since the cooling agents in the aerosol propellant freeze the larynx .
Cognitive impairments from VSU include a reduced attention span, short-term memory deficits, problem solving difficulties, and impairments to visual-spatial skills. The severity can range from mild impairment to severe dementia . Cognitive impairments associated with VSU appear to be cumulative, but one study found that when controlling for socioeconomic disadvantage the differences in cognitive skills among people reporting VSU were not statistically significant .
Forms of neurological disorders, including Parkinson’s disease, appear to be linked to VSU . The neurological damage caused by VSU is considered to be cumulative; chronic, long-term VSU is more likely to cause permanent brain injury or death than is infrequent VSU. Early studies suggested that brain injury associated with VSU was permanent , but recent evidence suggests that significant recovery from the effects of VSU is possible where abstinence occurs prior to the development of cerebellar atrophy .
Volatile substances can cross the placental barrier, and prenatal exposure is associated with: spontaneous abortion; low birthweight; prematurity; developmental delays; neurobehavioral problems; physical malformations; and behavioural issues later in life .
VSU is associated with a variety of social harms that involve the individuals who use volatile substances, their families, their communities, and wider society . While it is not possible to draw a causal relationship between VSU and the social effects, VSU is associated with social issues, including :