Inhalant Use Disorder

Overview

Inhalants include volatile chemical substances that produce fumes which may be inhaled. This can include glues, aerosols, paint thinners, solvents, lighter fluid, gasoline, and so on.

The use of inhalants is often observable by the method of sniffing or huffing the inhalants. Individuals may spray inhalants into paper or plastic bags and sniff them, or inhale fumes from an inhalant-soaked rag. Aerosols may be sprayed directly into the mouth or nose.

This problematic pattern of inhalant use can result in multiple acute and long-term health complications, and may also result in death. 

While no sex-based differences are generally reported in the prevalence of the disorder, it is considered to be rare among females in adulthood. Individuals are most likely to develop the disorder in adolescence, and it typically remits in adulthood.

Multiple factors including genetic, temperamental, and environmental factors are considered in its aetiology, and significant comorbidities typically exist. 

While no treatment modalities specifically target Inhalant Use Disorder, psychosocial intervention aiming to manage substance use disorder is typically considered to be effective. 

Signs and Symptoms

The signs and symptoms of inhalant use disorder include: 

1. Use of inhalant substance for longer than intended
2. Use of larger amounts of inhalant substance than intended 
3. Desire to reduce or stop the use of inhalants
4. Repeated unsuccessful attempts to cut down on the use of inhalant substance
5. Spending significant amounts of time trying to procure, use, and recover from the use of the inhalant substance 
6. Craving use of the inhalant substance 
7. Being unable to complete occupational, academic, or personal responsibilities due to persistent use of the inhalant substance 
8. Having problems with friends, family, and other close ones due to the use of inhalant substance 
9. Giving up on hobbies and work-related activities due to inhalant use 
10. Needing to use increased amounts of the inhalant substance in order to feel its effects

Risk Factors 

While no sex-based differences are reported in the prevalence of Inhalant Use Disorder in adolescence, the disorder is claimed to be very rare among females in adulthood. While individuals are reported to engage in inhalant use in adolescence, for a majority of individuals, this behavior does not turn into Inhalant Use Disorder.

The disorder is also known to remit in early adulthood, with the prevalence declining significantly among individuals in their 20s.

In cases of individuals who retain the disorder into adulthood, there is a significant likelihood of several severe problems including substance use disorders, antisocial personality disorder, suicidal ideation, and so on.

The disorder is more common among socioeconomically disadvantaged groups, which may be attributable to the relatively inexpensive nature of inhalants in comparison to other substances. 

Several factors are implicated in the proposed aetiology of Inhalant Use Disorder. A genetic influence is often seen through the heritability of a risk-seeking propensity known as ‘behavioural disinhibition’.

Behavioral disinhibition is explained as a tendency to deviate from societal norms and take on dangerous situations in significantly adverse conditions. This tendency is often observed to be genetic, and increases an individual’s risk of conduct disorders, and multiple substance use disorders.

A high likelihood of developing inhalant use disorder also exists among individuals who have family members with the disorder. 

A significant contribution is also made by environmental factors, such as stressful life events. Childhood maltreatment and negligence can be associated with the start of inhalant use and its progression of Inhalant Use Disorder.

Early exposure to and use of substances such as alcohol or tobacco have been associated with a higher lifetime prevalence of Inhalant Use Disorder. The actual availability of inhalant substances also plays a major part in contributing to the risk of development of Inhalant Use Disorder.

Since inhalant substances such as glue, aerosols, gasoline, and so on, are both legally and widely available for use, the risk of misuse is heightened. 

Inhalant Use Disorder is associated with a multiplicity of comorbidities, many of which are likely to precede its development. Individuals with dysthymia, anxiety disorders, panic disorder, specific phobia, antisocial personality disorder, and conduct disorder are likely to have a greater risk of developing Inhalant Use Disorder. 

Diagnosis 

A thorough clinical assessment is carried out as part of the diagnostic process. Asking appropriate questions with regards to the possession of inhalants is important as the identification of Inhalant Use Disorder simply on the basis of overt symptomatology can be challenging.

Behavioral changes, such as decline in occupational or academic performance and shifts in social behavior, as well as neuropsychiatric changes such as excessive confusion, problems with concentration, or irritability should be looked out for and reported during the assessment. 

Certain screening instruments are available to diagnose the disorder, including the Volatile Solvent Screening Inventory and the Comprehensive Solvent Assessment Interview by Howard and colleagues. 

The DSM-5 provides the following criteria for the diagnosis of Inhalant Use Disorder: 

A. A problematic pattern of use of a hydrocarbon-based inhalant substance leading to clinically significant impairment or distress, as manifested by at least two of the following, occurring within a 12-month period:

1. The inhalant substance is often taken in larger amounts or over a longer period than was intended.
2. There is a persistent desire or unsuccessful efforts to cut down or control use of the inhalant substance.
3. A great deal of time is spent in activities necessary to obtain the inhalant substance, use it, or recover from its effects.
4. Craving, or a strong desire or urge to use the inhalant substance.
5. Recurrent use of the inhalant substance resulting in a failure to fulfil major role obligations at work, school, or home.
6. Continued use of the inhalant substance despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of its use.
7. Important social, occupational, or recreational activities are given up or reduced because of use of the inhalant substance.
8. Recurrent use of the inhalant substance in situations in which it is physically hazardous.
9. Use of the inhalant substance is continued despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by the substance.
10. Tolerance, as defined by either of the following:

• A need for markedly increased amounts of the inhalant substance to achieve intoxication or desired effect.
• A markedly diminished effect with continued use of the same amount of the inhalant substance.  

Specifying the specific inhalant being used is also part of diagnosing the disorder appropriately. 

Treatment 

There is a paucity of research on interventions aimed specifically at Inhalant Use Disorder. Supportive care is suggested. Pharmacological intervention is rarely considered, and depends greatly on symptoms exhibited.

While no approved medication exists specifically for Inhalant Use Disorder, individuals may be treated with anticonvulsants such as carbamazepine or an antipsychotic such as haloperidol.

Benzodiazepines are not suggested for use, as they can worsen the depressive effects of inhalants. Owing to a potential risk of abnormal heart rate (cardiac arrhythmia), adrenergic drugs are also best avoided. 

Psychosocial approaches targeting substance use disorders are considered to be effective in managing Inhalant Use Disorder as well. It is also important, here, to consider that the disorder typically does not appear in isolation.

Individuals with Inhalant Use Disorder are likely to also present with other comorbidities, largely including other substance use disorders. Interventions such as Cognitive Behavioral Therapy and Motivational Interviewing have shown significant efficacy in managing symptoms of substance use disorders.

Community-based approaches may show considerable efficacy. Youth-based education programs, clinical management and counselling, as well as residential rehabilitation programs may be beneficial in incentivizing abstinence.

Involvement of family members or other close loved ones can increase the perceived social support among patients, and lead to more promising recovery.

Differential Diagnosis

1. Inhalant exposure from industrial or other accidents: This designation is used when findings suggest repeated or continuous inhalant exposure but the involved individual and other informants deny any history of purposeful inhalant use.

2. Inhalant use (intentional), without meeting criteria for inhalant use disorder: Inhalant use is common among adolescents, but for most of those individuals, the inhalant use does not meet the diagnostic standard in the past year.

3. Inhalant intoxication, without meeting criteria for inhalant use disorder: Inhalant intoxication occurs frequently during inhalant use disorder but also may occur among individuals whose use does not meet criteria for inhalant use disorder.

4. Inhalant-induced disorders (i.e., inhalant-induced psychotic disorder, depressive disorder, anxiety disorder, neurocognitive disorder, other inhalant-induced disorders) without meeting criteria for inhalant use disorder: Criteria are met for a psychotic, depressive, anxiety, or major neurocognitive disorder, and there is evidence from history, physical examination, or laboratory findings. Yet, criteria for inhalant use disorder may not be met.

5. Other substance use disorders, especially those involving sedating substances (e.g., alcohol, benzodiazepines, barbiturates): Inhalant use disorder commonly co-occurs with other substance use disorders, and the symptoms of the disorders may be similar and overlapping. 

6. Other toxic, metabolic, traumatic, neoplastic, or infectious disorders impairing central or peripheral nervous system function: Individuals with inhalant use disorder may present with symptoms of pernicious anemia, subacute combined degeneration of the spinal cord, psychosis, major or minor cognitive disorder, brain atrophy, leukoencephalopathy, and many other nervous system disorders.

7. Disorders of other organ systems: Individuals with inhalant use disorder may present with symptoms of hepatic or renal damage, rhabdomyolysis, methemoglobinemia, or symptoms of other gastrointestinal, cardiovascular, or pulmonary diseases. A history of little or no inhalant use helps to exclude inhalant use disorder as the source of such medical problems.

Comorbidity

Inhalant use disorder commonly co-occurs with adolescent conduct disorder and adult antisocial personality disorder. Adult inhalant use and inhalant use disorder also are strongly associated with suicidal ideation and suicide attempts.

Specialist 

A primary healthcare provider may be able to recognize symptoms of Inhalant Use Disorder, and upon clinical interviewing and a more concrete determination of the diagnosis, may refer patients to psychiatrists, clinical psychologists, or rehabilitation therapists.

Since the disorder may be present in adolescents, paediatric practitioners may be involved in initial assessment.