What Does Meth Do To Your Brain?

Crystal meth, known formally as methamphetamine, is an extremely powerful psychostimulant drug and is a member of the amphetamine family. It is one of the most potent stimulants known and can produce extreme euphoria, heightened alertness, increased confidence, powerful sexual urges, and gives the user a very large increase in energy.

Meth does a great deal of damage to the brain. In general, some behaviors which may emerge during meth use include:

  • Withdrawal from Family and Social Life
  • Increased Absences from Work
  • Erratic or Unusual Behavior
  • Failure to Keep Plans
  • Frequent Appeals to Borrow Money
  • Decreased Emphasis on Personal Hygiene

How Meth Affects The Brain

Meth produces extremely potent neurological effects, which over time can actually physically change the way the brain is wired and operates. The main way that meth works is through amplifying certain neurotransmitters such as dopamine, serotonin, and norepinephrine. There is a surge of all three of these neurotransmitters, but dopamine function is amplified much more strongly than the others. While amphetamines typically produce their effects by indirect means, meth acts in a much more intense way by directly stimulating neurotransmitter release as well as inhibiting reuptake, promoting the release of stored dopamine, and causing reverse transport in the dopamine receptors themselves.

Through chronic use, crystal meth is known to produce long-term effects on brain structure and function. Certain areas of the brain, such as the striatum and the ventral tegmental area, are strongly affected by meth use and this can have far-reaching consequences as far as higher-level reasoning is concerned. These are both parts of the limbic system, which is sometimes referred to as the “reward center” of the brain. As its name implies, it is responsible for feelings of reward, positive reinforcement, motivation, and plays a role in fine motor control. Meth-induced changes to the limbic system, and these two areas specifically, are known to accelerate addictive behavior, reduce empathy for others, and increase risk-taking behavior in general.

Sensory Effects

The sensory effects of meth are produced mainly through a surge in both dopamine and norepinephrine. The euphoria and rush of pleasure felt from meth use is mainly due to dopamine. This is a feeling of pleasure and excitement which is very intense and sudden. While dopamine function is more strongly stimulated, the most pronounced sensory effects are due to norepinephrine. This is both a neurotransmitter and a hormone when it is present in the blood and has very far-reaching effects. In the brain, norepinephrine is responsible for attention and focus, confidence, and aggression, and can increase sexual arousal. Additionally, excess levels of norepinephrine can temporarily speed up thought processes.

Emotional Effects

Meth has some very serious effects on a person’s emotional state. In the long term, this is expressed as a long-lived decrease in the ability to feel empathy or to sympathize with other people. In the short term, this can commonly manifest as a disregard for the feelings or importance of other people while under the influence of meth. The depression felt when not using meth will only increase the longer meth is used, as dopamine downregulation deepens with further use. This can worsen any pre-existing mental health issues related to depression and may take many years of abstinence for someone to fully recover. Likewise, someone who uses meth for long periods may become more prone to wild mood swings. Additionally, insomnia is a common symptom of regular meth use, and this can worsen someone’s overall state of mind. This can increase paranoia and delusional thoughts and feelings, furthering a person’s detachment from reality.

Behavioral Effects

Meth use can be characterized by excessive energy and talkativeness, insomnia, paranoia, and excessive fidgeting or tics such as pulling hair or picking of the face and arms. Excessive use may also result in psychotic-like states that might resemble an acute schizophrenic episode. Crystal meth is one of the few drugs that have a distinct lifestyle that frequently goes along with meth use. Insomnia is very common among people who use meth, with people staying awake for many days at a time. This can lead someone who is using meth to spend more time with other people who are using meth and staying awake for days on end.

How Meth Affects the Brain

Immediate Neurological Effects of Meth Use

Once meth has been used, it will rapidly enter the brain and cause an intense and long-lasting high. Some of the most general neurological effects include a speeding up of thought processes, an increase in confidence and awareness, and a feeling of intense euphoria. This is mediated through the release of three different neurotransmitters:

  • Dopamine: This neurotransmitter is a critical part of normal brain function and can produce feelings of reward and motivation among many others. The dopamine surge produced when someone uses meth creates a powerful rush of euphoria. While meth affects three distinct neurotransmitters, its most powerful effect is on dopamine where it not only increases the levels but also prevents dopamine reuptake and also releases dopamine which is stored inside neurons, causing levels to spike.
  • Norepinephrine: This is both a neurotransmitter in the brain and a hormone in the blood, and is a major component of the “fight-or-flight” response. In the brain, it acts to increase alertness, confidence, aggression, and can speed up reaction time. In the body, it acts as a stress hormone and promotes the release of glucose, adrenaline, increases heart rate and blood pressure, and increases blood flow to muscles. Normally, this chemical is released in bulk during fight-or-flight situations since it can raise physical performance for brief periods, increasing survival chances.
  • Serotonin: While serotonin is used in many different areas of the body, in the brain it is used as a mood enhancer and regulator. It helps promote feelings of wellbeing and happiness at normal levels, but the flood produced by meth use is overwhelming.

Long-Term Neurological Effects of Meth Use

The long-term risks of meth use are concerning, as there are currently no effective treatments. Using crystal meth can drastically alter the structure of the brain, and it is currently unknown if this damage can heal. Just a few of these long term effects include:

  • Amphetamine Psychosis: A common result from chronic crystal meth use, the symptoms can be indistinguishable from acute paranoid schizophrenia and can include a variety of symptoms such as visual/auditory/tactile hallucinations, paranoid delusions, disorganized thoughts, erratic behavior, and violent outbursts. 1, 2
  • Dementia-Like Symptoms: This can often take the form of slowed or clouded thinking involving processes like comprehension, reaction time, memory, and a greatly increased susceptibility to Parkinsonism. The exact cause is unclear but may involve damage to dopamine terminals in the brain. This particular type of brain damage has been shown to improve with prolonged abstinence, however, a return to brain function prior to meth use is unlikely. The effects meth has on the brain appear to resemble a roughly 4x acceleration of age-related neural degradation. 3, 4
  • Increased Anti-Social Behavior: This is shown in chronic meth users (rodents and humans) through MRI scans which show enlarged striatal volumes, as well as PET scans which show decreased brain glucose metabolism. Lowered brain glucose metabolism is an indicator of decreased or abnormal neurological function. The decrease in metabolism was closely correlated with the amount of meth used; higher doses of meth produced a greater decrease in brain glucose metabolism. In particular, the presence of increased striatal volumes is noteworthy, as this feature is closely associated with psychopathy and extreme antisocial behavior. On average, diagnosed psychopaths have 9.6% increased striatal volumes when compared to people who do not exhibit psychopathic tendencies.
  • Increased Susceptibility to Neurodegenerative Diseases: Meth use can increase the risk of neurological diseases through several mechanisms, including neuroinflammation, excitotoxicity, and increased permeability of the blood-brain barrier. This also increases the risk for Alzheimer’s, Parkinson’s, various dementias, as well as accelerating the progression of HIV-associated dementia and NeuroAIDS.

More About Crystal Meth Addiction


  1. BMC Psychiatry: Amphetamine-induced Psychosis – A Separate Diagnostic Entity or Primary Psychosis Triggered in the Vulnerable?
  2. Medical Journal of Australia: Amphetamine Psychosis – A Model for Studying the Onset and Course of Psychosis
  3. The Journal of Neuroscience: Loss of Dopamine Transporters in Methamphetamine Abusers Recovers with Protracted Abstinence
  4. The Journal of Neuroscience: Reduced Striatal Dopamine Transporter Density in Abstinent Methamphetamine and Methcathinone Users – Evidence from Positron Emission Tomography Studies with [11C]WIN-35,428
  5. Progress In Neurobiology: Mechanisms of Neurotransmitter Release by Amphetamines – A Review
  6. The Permanente Journal: The “Party” Drug Crystal Methamphetamine – Risk Factor For The Acquisition of HIV
  7. Current Drug Abuse Reviews: Mechanism of Action of Methamphetamine within the Catecholamine and Serotonin Areas of the Central Nervous System
  8. The Journal of Neuroscience: Loss of Dopamine Transporters in Methamphetamine Abusers Recovers with Protracted Abstinence
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