Posted on July 23rd, 2014
Methamphetamine is one of several drugs of abuse classified as central nervous system stimulants. However, the drug produces more powerful effects than other stimulants and its repeated use can easily trigger the brain changes that foster drug dependence and drug addiction. In a study published in May 2014 in the journal Addiction Biology, a team of Taiwanese researchers investigated the underlying mechanisms of methamphetamine-related brain damage. These researchers found that chronic meth users may experience a sharp decline in normal levels of a specific protein that helps protect the brain’s nerve cells.
Methamphetamine Abuse and Addiction
Like the vast majority of substances capable of producing addiction, all stimulant drugs of abuse increase levels of a specific chemical that allows the brain to produce pleasurable sensations. In turn, repeated alteration of the levels of this chemical plays a crucial role in the long-term brain changes associated with both physical dependence and the onset of addiction. Methamphetamine is particularly dangerous to repeated users because it triggers larger changes in the brain’s pleasure center than either amphetamine or cocaine (the two other most well-known addictive stimulants). In addition, the drug stays in circulation much longer than cocaine. These characteristics help explain methamphetamine’s notable power as an addictive substance. Officially, people addicted to the drug have a condition called stimulant use disorder.
Methamphetamine and Brain Damage
When taken repeatedly over time, methamphetamine can produce lasting damage in the nerve cells located in the brain’s pleasure center, as well as nerve cells in other locations. In addition, the drug is known for its damaging effects on support cells in the brain that help protect nerve cells from contagious microorganisms and remove degraded nerve cells from active duty. Known potential consequences of methamphetamine’s impact on brain health include memory impairment, memory loss, a reduced ability to think clearly or logically, a reduced ability to maintain focus and attention, and a reduced ability to regulate violent or aggressive urges. The drug’s brain impact can also lead to the highly debilitating state called psychosis, which commonly includes symptoms such as sensory hallucinations, delusional and paranoid thought processes and the abnormal repetition of certain body movements. Some of the damaging brain effects of chronic methamphetamine use may be permanent, while others may resolve partially or fully if a meth user stops using the drug for extended periods of time.
Explaining Meth-Related Brain Damage
In the study published in Addiction Biology, researchers from three Taiwanese institutions explored the potential role of declining levels of a protein called BDNF in promoting the brain damage found in chronic methamphetamine abusers and addicts. Under normal circumstances, BDNF provides the brain with critical protection by helping nerve cells grow, reach maturity and stay in good working order. In addition, the protein plays an essential role in basic brain functionality by supporting the chemical and physical adaptations required for learning new information and storing that information in memory.
For their study, the researchers recruited 59 people diagnosed with methamphetamine abuse, as well as a second group of 59 generally healthy individuals who did not use the drug. The methamphetamine abusers had stopped actively taking the drug and were in the early stages of withdrawal. Over a period of three weeks, the researchers used blood tests to measure the levels of BDNF in both groups of study participants and compared the average levels between the groups. After completing this comparison, they found that the participants going through methamphetamine withdrawal consistently had much lower levels of the protein in circulation than the participants who had never used the drug.
Similar declines in BDNF levels have been found in chronic amphetamine users. The authors of the current study undertook their project, in part, because not much work has been done to assess the levels of the protein in active methamphetamine users or in people going through the early stages of methamphetamine withdrawal. Based on their findings, they concluded that chronic meth users may develop particularly severe disruptions in the production of BDNF; in turn, this protein disruption may lead to a decline in nerve cell protection that helps explain the brain damage associated with long-term methamphetamine intake. The study’s authors note that laboratory experiments indicate that BDNF levels start to increase in abstinent amphetamine users after roughly 30 days. Future researchers will need to determine if a similar rebound occurs in abstinent methamphetamine users.