Cocaine use stimulates the brain and central nervous system, and can result in a variety of adverse outcomes. The effect that cocaine has on an individual depends on a number of factors. These include:

• how much cocaine is taken
• the method of use
• the form and purity of the cocaine
• the height and weight of the user
• the user’s current physical and mental health status
• the user’s previous experience with cocaine (i.e. new user vs frequent user)
• whether other substances (alcohol, tobacco, medications, or other illicit drugs) are used at the same time as cocaine.

There are a variety of physical health risks associated with cocaine use. Many of these risks are very serious and can result in severe short- and long-term consequences for the user.

Short-term effects

The short-term physical effects of using cocaine include:

• happiness and confidence
• talking more
• feeling energetic and alert
• anxiety
• paranoia
• irritability and agitation
• headaches
• dizziness
• feeling physically strong and mentally sharp
• reduced appetite
• dry mouth
• enlarged (dilated) pupils
• higher blood pressure and faster heartbeat and breathing 
• higher body temperature
• increased sex drive
• insomnia
• unpredictable, violent or aggressive behaviour
• indifference to pain

These effects are generally short-lived (less than 30 minutes).

If a large and/or strong batch of cocaine is taken, an overdose may occur. Overdoses can involve:

• nausea and vomiting
• extreme anxiety
• chest pain
• panic
• extreme agitation and paranoia
• hallucinations
• tremors
• breathing irregularities
• kidney failure
• seizures
• stroke
• heart problems.

Long-term effects

If cocaine is used regularly for an extended period of time, long-term effects can include:

• dependence
• lung conditions such as bronchitis
• anxiety, paranoia and psychosis
• sexual dysfunction
• kidney failure
• stroke
• seizures
• hypertension and irregular heartbeat
• heart disease and death.

The way in which cocaine is used can further impact on the health of the user. For instance:

• Snorting cocaine can lead to nosebleeds, sinus problems, and damage to the inside of the nose.
• Injecting cocaine with unsterile or shared equipment increases the risk of contracting blood borne viruses (HIV, hepatitis B and C), blood poisoning (septicaemia), tetanus, or skin abscesses.
• Injecting cocaine can also result in blocked blood vessels, leading to inflamed blood vessels, abscesses, and serious damage to the liver, heart, or kidneys.

Dependence

Regular use of cocaine may also lead to dependence (addiction). Dependent users develop a tolerance to cocaine, and need to take larger doses of the drug to achieve the same effect and feel ‘normal’. The urge to use cocaine can become more important than other activities in their lives, resulting in poor physical and mental health, social and financial problems, and family and social breakdown.

Dependence can develop after a relatively short period of use. Exactly how long it takes may depend on the way cocaine is used: smoking or injecting may lead to dependence in weeks or months, while dependence associated with snorting may take months or years to develop.

Psychosis

Regular heavy cocaine use may in some cases result in the development of a cocaine-induced paranoid psychosis. A psychosis involves a loss of contact with reality, and the effected person may have paranoid beliefs and experience hallucinations. In some instances, the psychosis may be associated with aggression and suicidal behaviours. These symptoms usually disappear a few days or weeks after the person stops using cocaine.

A state of extreme agitation (‘agitated delirium syndrome’) can also occur among some people who use cocaine frequently and may result in heart attack and death.

Australians who used cocaine in the past 12 months are significantly more likely to have been diagnosed with or treated for a mental illness (26%), compared to Australians who did not use cocaine (18%).

In 2022-23 there were 985 hospital separations due to the use of cocaine.

Australians who used cocaine in the past 12 months were significantly more likely to report high/very high levels of psychological distress, compared to those who had not used cocaine.

The reference guide used by clinicians to diagnose mental health disorders is known as the Diagnostic and Statistical Manual of Mental Disorders (DSM). The most recent version of the manual, the Diagnostic and Statistical Manual of Mental Disorders – 5th Edition (DSM-5), was released in May 2013.

DSM-5 Diagnostic Criteria

According to the DSM-5, there is one main cocaine-related mental health disorder: a stimulant use disorder. This is defined as:

A pattern of amphetamine-type substance, cocaine, or other stimulant use leading to clinically significant impairment or distress, as manifested by at least two of the following, occurring within a 12-month period:

1. The stimulant 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 stimulant use
3. A great deal of time is spent in activities necessary to obtain the stimulant, use the stimulant, or recover from its effects
4. Craving, or a strong desire or urge to use the stimulant
5. Recurrent stimulant use resulting in a failure to fulfil major role obligations at work, school, or home
6. Continued stimulant use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the stimulant
7. Important social, occupational, or recreational activities are given up or reduced because of stimulant use
8. Recurrent stimulant use in situations in which it is physically hazardous
9. Stimulant use 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 stimulant
10. Tolerance, as defined by either of the following:
    a    A need for markedly increased amounts of the stimulant to achieve intoxication or desired effect
    b    A markedly diminished effect with continued use of the same amount of the stimulant.
    
    Note: This criterion is not considered to be met for those taking stimulant medications solely under appropriate medical supervision, such as medications for attention-deficit/hyperactivity disorder or narcolepsy.
     
11. Withdrawal, as manifested by either of the following:
    a    The characteristic withdrawal syndrome for the stimulant (refer to Criteria A and B of the criteria set for stimulant withdrawal, p. 569).
    b    The stimulant (or a closely related substance) is taken to relieve or avoid withdrawal symptoms.
    
    Note: This criterion is not considered to be met for those taking stimulant medications solely under appropriate medical supervision, such as medications for attention-deficit/hyperactivity disorder or narcolepsy.

A mild stimulant use disorder is defined as the presence of 2-3 of the above symptoms.

A moderate stimulant use disorder is defined as the presence of 4-5 of the above symptoms.

A severe stimulant use disorder is defined as the presence of 6 or more of the above symptoms.

In 2021, there were 82 overdose deaths in Australia which involved cocaine, of which the majority (83%) occurred among men. Most of these deaths (94%) were unintentional.

The vast majority  of drug-induced deaths are due to overdose, however a small number of cocaine-related deaths unrelated to overdose may be excluded from the above figure.