Substances of abuse

Alcohol affects the release of dopamine, noradrenaline and endogenous opioids, producing an activated state that is pleasurable. It specifically acts at the gamma-aminobatyric acid type A (GABA-A) receptor, thus accounting for its anxiolytic properties. At higher concentrations, alcohol also blocks glutamatergic N-methyl-D-aspartate (NMDA) receptors, resulting in amnesia and cerebral depressant effects (see Table 20.1). Ten grams of alcohol per hour will cause an increase in blood alcohol concentration levels to between 0.01% and 0.02%, with lower concentrations possible where there is marked tolerance, and higher concentrations found in females of small stature. Hazardous intake by young people tends to lead to harm as a result of behaviours associated with acute intoxication (e.g. motor vehicle accidents, assaults, drownings and suicides). Older people experience the sequelae of long-term hazardous use, such as medical complications.

TABLE 20.1 Alcohol effects

Amphetamines are a group of synthetic drugs that include ‘speed’ (amphetamine sulphate, dexamphetamine), ‘meth’ (methamphetamine or methylamphetamine) and ‘crystal meth’ (methamphetamine hydrochloride). They come in many forms (e.g. crystalline, paste, powder and pills) and in varying strengths. They are generally ingested or injected, although they can be snorted or smoked depending on what preparation they are in. They produce their stimulating effects through releasing dopamine and noradrenaline from pre-synaptic nerve terminals. Intoxication is associated with euphoria, increased physical activity, confidence, stamina and reduced need for sleep. Use that is greater than twice per week is more likely in dependent individuals. Dependence is also more likely among those who inject (50% likelihood). Long-term risks include those resulting from injecting if this is the mode of use. Teeth grinding, appetite suppression and weight loss, headache, chronic psychosis, mood instability, unpredictable behaviour and violence may also occur.

Benzodiazepines act on GABA-A receptors, resulting in anxiolytic, hypnotic, sedative and anticonvulsant effects. The duration of effects varies according to the half-life of the benzodiazepine consumed. Abuse as a component of polysubstance abuse, dependence in conjunction with alcohol or other drug dependence, and long-term dependence in the context of longstanding repeat prescriptions are the commonest problematic patterns of use. Dependence can follow 3 months of regular use, and in some instances has been noted to occur much earlier, particularly if there is already dependence on a sedating substance. Sleep impairment, sedation, cognitive impairment and falls in the elderly are some of the problems associated with dependence.

Cannabis is usually smoked, although it can be ingested. Delta-tetrahydrocannabinol (THC), the psychoactive component of the cannabis plant, binds to cannabinoid receptors (CB1) throughout the central nervous system. Intoxication is experienced within minutes of inhalation and lasts 3–4 hours. It produces transient euphoria and grandiosity, followed by sedation, lethargy, impaired short-term memory and concentration, slowed thinking, impaired judgment and motor coordination, perceptual distortions and a sense that time is passing slowly. Anxiety is a common unwanted effect. Dependence can develop. Cannabis use (especially if early onset) increases the risk of developing a psychotic disorder, as well as depression. It also impacts negatively on treatment outcomes in psychosis.

Cocaine inhibits the reuptake of noradrenaline, dopamine and serotonin. It tends to be either snorted in an intermittent binge pattern by employed individuals or injected (less frequent) by those who inject other substances. The acute effects of cocaine are largely indistinguishable from amphetamine, although its duration of action is significantly shorter. Acute and chronic use may result in a number of serious cardiac complications. Chronic cocaine use can result in psychosis, mania, depression or anxiety.

Ecstasy (N-methyl-3,4-methylenedioxy-amphetamine) is a synthetic compound that has both stimulant and hallucinogenic properties (due to its effects on noradrenaline, serotonin and possibly dopamine). Young people use ecstasy because it keeps them awake for long periods, increases sensory perception, confidence and energy levels, induces euphoria and makes them feel love, friendship and intimacy. It is usually sold as a tablet or capsule and taken orally, although some may also inject it. Young people predominantly take it in social settings in non-dependent patterns. It causes an increase in body temperature, which may, in combination with intense physical activity, a hot environment and minimal fluid intake, lead to severe heatstroke. With regular use, recurrent anxiety and panic disorders, as well as severe depression and psychotic symptoms (especially paranoid ideation), may also occur. There is evidence suggestive of neuronal damage to serotonin producing neurons after prolonged heavy use.

Hallucinogens include a variety of substances, such as lysergic acid diethylamide (LSD), phenylalkylamines (mescaline) and psilocybin (from mushrooms). The effects are highly variable depending on the user, the expectations of the user and the situation in which it is taken. The central experiences of intoxication are perceptual distortions and hallucinations, as well as depersonalisation and derealisation. Synesthesias may occur. Mood effects vary and anxiety can be prominent, reaching panic. Delusions and agitation can occur. Tolerance arises, but withdrawal syndromes have not been described. Most use is intermittent. Flashbacks are distressing perceptual disturbances reminiscent of intoxication which recur in the absence of continued use.

Heroin is a short-acting opioid that in Australia is most commonly injected. Some smoke it. First pass metabolism is extensive, so it is seldom taken orally. Unwanted effects include respiratory depression (can be fatal), pupillary constriction, nausea, vomiting and constipation. Associated hazards from use are secondary to the behaviours surrounding injecting (e.g. hepatitis C occurs in up to 15%), as well as the lifestyle associated with obtaining the substance. Approximately 30% of those who use heroin develop dependence. Heroin-dependent individuals must use two to four times per day to avoid withdrawals due to the short half-life of the drug. Morphine and slow-release morphine preparations are also abused through supplies diverted after prescription. Methadone is a longer acting opioid prescribed for opioid dependence and in chronic pain. It is also abused.

Inhalants are cheap and easily available. They comprise a wide range of household and commercial products (e.g. petrol, paint thinners, glues, solvents and spray paints). They are physically toxic, and long-term use is associated with significant neuro-cognitive disturbances. Deaths from acute inhalant use are largely associated with ‘sudden sniffing death’ (fatal ventricular arrhythmias) or accidental injury (related to impulsive risk-taking behaviour and impaired motor skills) while intoxicated. Dependence can occur.

Nicotine, the primary addictive component of tobacco, binds to nicotinic acetylcholine receptors, effecting the release of a number of neurotransmitters, including dopamine, noradrenaline and serotonin. A number of chemicals found in cigarette smoke are thought to be carcinogenic, while other chemical gases, such as carbon monoxide, impair oxygen transport in the body, or are irritants to the respiratory tract. The majority of smokers are dependent on nicotine. Those who smoke within half an hour of waking are likely to be dependent. There are much higher than expected rates of nicotine dependence in people with alcohol dependence and those with mental illnesses.

Caffeine is the most widely used substance in our community. A typical 150 mL cup of brewed coffee contains 100–150 mg of caffeine, instant coffee contains 30–100 mg of caffeine, and tea contains 30–100 mg of caffeine. Symptoms of toxicity include anxiety, insomnia, nausea and abdominal discomfort, diuresis, and elevated blood pressure and heart rate. These symptoms occur at doses above 500 mg, or more if tolerant. Dependence is common and withdrawal symptoms are most commonly headache and cognitive slowing.

Prevalence and costs

Epidemiological surveys consistently show that most people who report using substances do not do so on a regular basis (see Table 20.2). Experimental use is more common among adolescents and young people, while more frequent use is more prevalent in the 20–29-year-old age group. However, individuals with substance use disorders who present for treatment are typically older. While single episodes of use can cause problems (e.g. driving while intoxicated), individuals who use more frequently are more likely to experience deleterious mental and physical health consequences. Indeed, substance use and mental disorders frequently co-occur, and such comorbidity substantially impacts upon treatment outcomes for both conditions.

TABLE 20.2 Lifetime and recent (last 12 months) use of substances in Australia in those 14 years and over

Source: National Drug Strategy, Household Survey 2008.

Substance use and misuse are important contributors to workplace injury, loss of productivity, relationship breakdowns, violence and crime, as well as illness and disease. The cost to our society is enormous, estimated in the tens of billions of dollars, with licit drugs accounting for the bulk of the costs (56% tobacco, 27% alcohol, 15% illicit drugs). Such figures are startling, and highlight the importance of early detection and treatment.

Patterns of use

An individual’s pattern of substance use can range from experimental, through social/recreational to problem use (i.e. a substance use disorder). It is important to consider this pattern of use in addition to the quantity of substance consumed. The terms abuse and dependence are used to describe patterns of problem use (see Table 20.3); dependence is generally regarded as the more reliable, robust and useful construct.

TABLE 20.3 DSM–IVTR criteria for abuse and dependence (synopsis)

Screening and assessment

Given the high rate of morbidity associated with regular substance use, screening should be routinely conducted across all clinical settings. Presentations in which there are mental health issues, relationship or work problems, repeated requests for psychotropic medication (especially benztropine, anxiolytics or analgesics), and frequent attendances to different doctors, are all examples of when the clinician needs to be particularly mindful of the need to screen for substance use disorders. Simple screening methods include:

The CAGE questionnaire. This screener consists of four questions, and scoring positive for two items is highly indicative of dependence on alcohol. The four questions are:

Have you ever felt that you should Cut down on your drinking?

Have people Annoyed you by criticising your drinking?

Have you ever felt Guilty about your drinking?

Have you ever had a drink first thing in the morning to steady your nerves or get rid of a hangover (an Eye-opener)?

The CAGE questionnaire is useful as a very quick screen, but it is not good at determining the severity of alcohol use, nor hazardous use that is non-dependent.

Alcohol use disorders identification test (AUDIT). This quick, ten-item questionnaire is good at identifying risky levels of alcohol use, as well as the severity of alcohol dependence.

Alcohol, smoking and substance involvement screening test (ASSIST). This questionnaire measures the frequency of substance use (lifetime and 3-month) across nine drug categories. There is also a brief intervention package associated with the screener that is freely available from the WHO website.

History

When assessing for substance use, a non-judgmental approach during history taking is imperative so as to avoid defensive answers. Alcohol should be quantified as the number of standard drinks (1 standard drink contains 10 g of alcohol), and all alcoholic beverages in Australia must now have this displayed on the label (see Figure 20.1). It is useful to understand the local street terms for available substances (e.g. ‘ice’, ‘whiz’ or ‘goey’ referring to methamphetamines), and to know the quantities by which it is consumed or purchased. For example, methamphetamine is often sold as ‘points’ (very loosely equating to 0.1 g). There is enormous variation in the purity of illicit substances, so the cost may be the best way to define the amount of substance being consumed.

FIGURE 20.1 Standard drinks

The patient should be asked about use of all drugs of abuse in a systematic manner (see Box 20.1). Use of more than one substance to problematic levels should be expected, as polydrug use is common. It is particularly important to ask when the substance was last used, as this will often help identify current issues that the patient is presenting with (e.g. problems related to intoxication or withdrawal). Features of intoxication vary depending on the substance consumed, and clinicians need to familiarise themselves with these effects (see below). Such information also assists in the assessment of abnormal mental states, particularly if there is a history of a coexisting mental disorder.

BOX 20.1 Substance use history

Areas of enquiry in a substance use history include:

• substance/s used (amount typically used or cost if undefinable otherwise)

• when use began

• what the pattern is (e.g. frequency and mode of use) now and recently

• route of administration, and history of safe injecting if relevant

• features of DSM–IVTR abuse or dependence

• consequences of use (e.g. physical, psychological, social, vocational and forensic)

• past treatment

• periods of abstinence

• when last used

• reasons for use

• what the person wants to do now (readiness for change), and

• psychiatric symptoms indicative of a co-occurring disorder.

As with many areas of psychiatry, obtaining history from other sources can lead to a greater understanding of the extent of substance use, the effects of intoxication, as well as associated problems. Many people have difficulty recalling their intake spontaneously. It is often helpful to ask them to recount what they have consumed over the past week, working backwards on a daily basis, from yesterday to 1 week ago. You should establish whether the amount consumed was typical for them, and, if not, how it varied from their usual intake.

Mental state examination

Features to look for depend on the substance used, but can include:

evidence of poor self-care, appearance and behaviour suggestive of intoxication, such as slurred or rapid speech, disinhibition, sedation, irritability or lability of affect

hallucinations (e.g. visual, auditory and tactile)

persecutory beliefs, and

cognitive impairment (acute or chronic).

Physical examination

Features to look for include:

signs of intoxication, such as ataxia, pupillary constriction (opioids), dilation (stimulants) or conjunctival injection (cannabis); or withdrawal (e.g. sweating, tremor, piloerection or pupillary dilatation (opioids))

signs of alcoholic liver disease

evidence of injecting drug use (e.g. needle-tracks), and

sequelae of injecting drug use (e.g. infected injecting sites, endocarditis and hepatitis).

Investigations

Clinical judgment should determine which investigations are relevant. However, the following should be considered depending upon the substance being used:

full blood count and liver function tests (about 75% of people with raised mean corpuscular volume (MCV) and gamma-glutamyl transferase (GGT) are likely to have an alcohol disorder)

screening for viral hepatitis antigens and antibodies, and for HIV (consent should be obtained for these investigations)

electrocardiography (ECG) (particularly relevant for patients taking methadone which can cause QT prolongation), and

urine drug screen.

Substance-induced disorders

This important concept is defined in DSM–IVTR as:

It is a disorder directly caused by the effects of a substance.

The episode is above and beyond what would be expected during intoxication/withdrawal.

It develops within 1 month of intoxication or withdrawal.

It subsides once the substance is eliminated.

It is not due to delirium or other mental disorder.

It is important to note that heavy use of psychoactive substances can mimic the symptoms of almost any mental disorder, and should be considered a differential diagnosis for most presentations. Table 20.4 shows the range of disorders that can be induced by psychoactive substance use. In addition to induced disorders, many substances can cause symptoms, but not enough to justify a full diagnosis.

Management

Clinician attitude

Clinicians may experience a negative attitude towards working with people with substance use disorders, particularly those who are dependent. It is helpful to remember that these disorders may take a chronic relapsing course. Many respond well, over time. Rapid change may be more likely in patients with less severe conditions, rather than if heavily dependent, but change is possible and frequently occurs even in those who appear to be the least capable of it. An approach that is non-judgmental, empathic and encouraging is necessary. It needs to occur within a harm-reduction framework, appreciating that, for some, complete cessation of harmful substance use is not possible.

Treatment options

Treatment options will depend upon a variety of parameters. Patterns of use need to be considered, and whether the person is dependent or not. The goals of treatment need to be negotiated with the patient. Many would like to be able to continue to take the substance, but in safe controlled amounts. With most people who are dependent, the usual aim of treatment is abstinence rather than controlled intake due to the high rates of relapse when controlled use is attempted. Alternatively, for some substances (e.g. opioid dependency), controlled substitution therapy may be the best option for reducing immediate risks (e.g. chaotic lifestyle and intravenous use), with the aim of drug cessation in the longer term.

The impact that the substance use is having on the person’s life and their awareness of the negative consequences must also be considered, together with their willingness to change and identification of current goals.

Motivational enhancement is a useful therapeutic strategy for patients with a substance use problem, and can be used throughout treatment. It is helpful to use the stages of change approach to map where the patient is, and focus your therapeutic approaches accordingly (see Table 20.5). However, it is important to note that such stages are relatively fluid, and can change rapidly depending on psychosocial circumstances (e.g. break-up of a relationship or resolution of crisis).

TABLE 20.5 Stages of change and motivational enhancement techniques

Conceptual stage	Description	Consider approach
Pre-contemplation	The individual is not thinking about change	Provide factual information about the effects of substance use. Avoid confrontation. Encourage considering change, offering an optimistic perspective
Contemplation	The individual is thinking about change within the next 6 months	Examine with the patient the pros and cons of change, as well as continuing intake. Consider the compatibility of these with their broader life and health goals. Acknowledge ambivalence
Action	The individual has commenced attempts to change their use	Assist patient to enact strategies to change pattern of use
Maintenance	The individual has made a change	Assist patient to address ongoing ambivalence, rehearse relapse-prevention strategies and develop new skills
Relapse	The individual returns to aspects of previous behaviour (not always a full relapse)	Support the patient and assist them to reengage with treatment as above

Co-occurring mental health disorders must also be considered. Substance use and mental disorders commonly co-occur, and integrated treatment should be offered for both conditions. This ensures that the patient understands the link between their substance use and mental disorder, and that common issues underpinning both disorders are addressed simultaneously.

Withdrawal management

The supervised management of withdrawal states is often referred to as ‘detox’ (detoxification), and should not be considered the main focus of treatment. In fact, only a very small percentage of patients subsequently remain substance free in the long term or are able to continue to use in a controlled fashion. Nevertheless, detoxification may be a starting point for change, and other treatment strategies (see below) should also be offered. Stimulant-like substances (e.g. methamphetamines) produce withdrawal states characterised by lethargy and dysphoria. Sedative substances (e.g. alcohol and opioids) produce withdrawal effects of overactivation, such as anxiety and autonomic arousal (see Table 20.6).

TABLE 20.6 Common withdrawal syndromes

Psychological strategies

Addressing the psychological processes involved in problem use is important, and should include concurrent treatment of coexisting mental health issues. Strategies include:

Brief intervention. This approach is effective for non-dependent levels of use. It involves feedback to the patient about their consumption levels in relation to known safe levels of use; specific advice about how to change and achieve goals; encouragement, emphasising self-efficacy; and an optimistic perspective.

Motivational enhancement. This is a therapeutic approach that avoids confrontation, acknowledges and examines ambivalence, and assists the patient to utilise inconsistencies in their present behaviours with identified goals, as a means of motivating change.

Relapse prevention skills. This set of techniques is learnt by the patient to prevent return to substance intake, particularly at times when there is high risk of use. It involves a behavioural analysis of substance-related behaviours, intervention that is tailored to the individual’s needs and the acceptance that temporarily lapsing back to use is possible but not catastrophic.

Cognitive behaviour therapy (CBT). CBT focuses on developing non-substance-related behavioural strategies, adaptive coping skills, and identifying and correcting any thinking errors.

Contingency management/behaviour modification. This strategy provides positive reinforcement for abstinence in structured treatment programs.

Acceptance and commitment therapy. This therapy involves the patient learning to accept what is out of their personal control and to focus on whatever is within their control to improve quality of life.

Twelve-step facilitation. This supports working through the 12 steps to achieve abstinence in conjunction with attendance at, for example, Alcoholics Anonymous or Narcotics Anonymous.

Therapeutic communities. These are residential treatment programs that focus on abstinence-based outcomes, generally over weeks to months. They use both individual and group therapies to address entrenched patterns of thinking and behaving relevant to the person’s substance use.

Pharmacotherapy

There are evidence-based pharmacological approaches to some but not all substance-dependence disorders (see Table 20.7).

TABLE 20.7 Pharmacological treatments used in substance-dependence disorders

Substance	Pharmacological options for management of dependence
Alcohol	Acamprosate, naltrexone and disulfiram
Benzodiazepines	Equivalent dose of diazepam and taper slowly
Heroin	Buprenorphine, buprenorphine/naloxone and methadone
Stimulants	Evidence lacking
Cannabis	Evidence lacking
Nicotine	Nicotine replacement therapies, bupropion and varenicline
Hallucinogens	Evidence lacking
Inhalants	Evidence lacking
Caffeine	Evidence lacking

Social aspects

Prohibition is a component of the policy adopted for substances such as heroin, cannabis and methamphetamines. Alcohol and tobacco are prohibited for people under certain ages in Australia, and are subject to legislation and taxation to regulate their use.

Harm minimisation is another component of Australia’s National Drug Strategy, and has three main elements:

Prescribing methadone to patients with heroin dependence is an example of a treatment that has harm reduction as its principal aim.