Methamphetamine increases the user’s level of dopamine; the brain’s natural, feel-good chemical. Drug use stimulates this area of the brain, rapidly releasing high levels of dopamine that reward and reinforce the behaviour. This makes the user want to repeat the experience time and again.

As frequency of consumption and dosage increase, so too does tolerance. The effect of the drug becomes increasingly less intense and a cycle of abuse inevitably begins with the user perpetually chasing the initial high.

Methamphetamine abuse has a profound effect on the brain’s chemical balance. Over time, the body adjusts to the presence of methamphetamine and is unable to function normally without it. If use stops, the body demands the drug by means of uncomfortable withdrawal symptoms.

Someone addicted to the drug will compulsively seek it out despite an awareness of the adverse consequences.


Like many drugs, methamphetamine increases the amount of the natural chemical dopamine in the brain. Dopamine is involved in motivation and creating a feel-good sensation, rewarding behaviour that stimulates this area of the brain. Methamphetamine rapidly releases high levels of dopamine, which reinforces drug-taking behaviour so that the user wants to repeat the experience, which leads to addiction.

In low to moderate doses, methamphetamine can elevate the user’s mood, increase wakefulness and physical activity, and decrease appetite. It can also cause faster breathing, a rapid or irregular heartbeat and increase blood pressure and body temperature.

At very high doses, it can cause psychosis, muscle breakdown, seizures and bleeding on the brain. Chronic high-dose use can lead to unpredictable and rapid mood swings, stimulant psychosis (such as paranoia, hallucinations and delirium) and violent behaviour.

Methamphetamine addiction, and addiction in general, is a disease of the brain that is not caused by a single factor. It is believed that addiction to methamphetamine and other drugs is caused by a number of factors, such as environment, psychology, genetics and brain chemistry. The most common causes and risk factors associated with methamphetamine addiction include:

Environmental Factors

Being exposed to addiction as part of daily life at a young age and having easy access to methamphetamine may make someone more likely to develop an addiction. Abuse, stress or trauma may also lead an individual to methamphetamine addiction.

Psychological Factors

People who are susceptible to peer pressure may be more likely to develop a methamphetamine addiction, alongside individuals who engage in risk-taking behaviour.

Genetic Predisposition

A family history of drug abuse and/or addiction increases the chances of developing a methamphetamine addiction. In addition, a family history of mental health disorders is known to heighten someone’s risk of developing addictions.

Changes in Brain Chemistry

Addiction is a disorder of the brain’s reward system and illness or injury can affect this area of the brain. Mental health issues linked to brain chemistry can also impact on someone’s chances of developing a methamphetamine addiction.

Alongside the emotional and cognitive issues mentioned above, there are several physical and behavioural signs that suggest an addiction to methamphetamine.

The most well-known sign of methamphetamine use is oral ulcerations, known as ‘meth mouth’. Some of the chemicals used to manufacture methamphetamine are caustic, meaning they burn skin, so when meth is vaporised and inhaled the soft tissue in the mouth is irritated or burnt. This leads to significant oral ulcerations and infections.

In addition, stimulants such as methamphetamine reduce the amount of saliva a person produces, resulting in a severe dry mouth, which promotes tooth decay.

Physical Symptoms

  • Weight loss
  • Severe dental problems (called ‘meth mouth’)
  • Intense itching, leading to skin sores from scratching
  • Changes in brain structure and function

Behavioural Symptoms

  • Anxiety
  • Confusion
  • Memory loss
  • Sleeping problems
  • Violent behaviour
  • Paranoia and hallucinations

Drug abuse is different to drug addiction. Drug abuse is often the first step on the road to addiction, and methamphetamine abuse can make it difficult for people to handle their usual responsibilities at work and at home. It may also lead people to behave in a way they wouldn’t usually and develop physical side effects.

Addiction means the user has a strong urge to take a drug, regardless of the consequences. An addiction develops once someone becomes more tolerant of the drug and needs to take more to achieve the same results and/or suffers from withdrawal symptoms without it. Methamphetamine is a highly addictive stimulant, and its use can lead to very strong psychological and physical dependence, especially if it is injected or smoked.

Methamphetamine addiction usually causes cravings, which means that, despite understanding that a drug has harmful effects, the person continues to take it.