Acute effects of methamphetamine
Acute or short-term effects of methamphetamine vary widely from person to person and depend on a range of factors such as how much has been taken and how, the person’s tolerance to the drug, and their physical and mental health. Effects of methamphetamine may fall along a continuum from pleasurable feelings and increased energy, through to toxicity or overdose.
Mild intoxication occurs when a small dose is taken. It produces the desired effects of drug taking. People who are mildly intoxicated with methamphetamine feel euphoric, confident and alert. They may have lots of energy for dancing, socialising, doing chores, or just staying awake. Effects can be long-lasting, up to 12 hours, while some people may be unable to sleep for a night or two due to residual stimulant effects. Typically, someone who occasionally takes methamphetamine would feel ‘normal’ again when the dopamine and serotonin systems have had a chance to replenish their stores after a couple of days.
Moderate intoxication occurs when a little too much is taken and can produce unwanted effects that include unpleasant mind states as well as uncomfortable physical effects such as teeth grinding, racing pulse and agitation. People sometimes use another drug that is sedating (alcohol, a pharmaceutical or an illicit drug like cannabis) to ‘come down’ if the effects become too uncomfortable or last longer than desired.
Toxicity, or overdose, occurs when too much methamphetamine is taken at once. Acute toxicity can occur at any time – it doesn’t only occur among people who are use a large quantity regularly. Any of these signs may indicate a medical emergency and an ambulance or medical assistance should be called.
Acute toxic effects of methamphetamine can include:
- cardiovascular effects, including increased heart rate and blood pressure, severe chest pain, arrhythmia, heart attack and stroke
- psychotic symptoms due to excess dopamine
- clinically significant overheating, muscle rigidity, spasms, and jerking due to serotonin toxicity
- psychiatric problems including anxiety, insomnia, irritability, psychosis and depression.
The come down
After using methamphetamine there is a short recovery period known as the ‘come down’ or ‘crash’. It is similar to a hangover from alcohol. The come down usually lasts for 1-3 days and is distinct from a withdrawal syndrome. In people who use methamphetamine regularly and are dependent, the come down may precede withdrawal.
Typical symptoms of the come down include depression and anhedonia (inability to experience pleasure), irritability, excessive sleep and hunger, and inability to focus. During the come down, some people may also experience psychosis symptoms and mood swings.
Effects of long-term regular use
While people who use methamphetamine occasionally over a long period may experience acute effects, people who use regularly over a longer time period are vulnerable to a range of other adverse effects that are related to chronic exposure.
Long-term methamphetamine use can cause enduring problems with brain function and structure that can result in memory impairment, problems with attention, impulse control and decision making. Most, if not all, of these functions can be restored if the person stops taking methamphetamine, although the process tends to be lengthy.
Other chronic issues include liver and kidney problems, skin problems, malnutrition, and a severe dental condition colloquially known as ‘meth mouth’. There are also higher than average rates of infectious diseases including hepatitis and HIV among people who use methamphetamine regularly.
People may also experience mood disturbances, anxiety and psychosis. Mental health symptoms may persist for weeks or months after stopping use.
There is a documented dependence syndrome with methamphetamine, which is the same as the general dependence syndrome for all drug dependence.