Amphetamines are a class of stimulant drugs that primarily affect the central nervous system. These substances encompass various compounds, including both legally prescribed medications like Adderall and Vyvanse, and illicitly manufactured substances such as crystal methamphetamine. They are recognized for their capacity to accelerate messages between the brain and body. This broad category of drugs is utilized therapeutically for conditions such as attention deficit hyperactivity disorder (ADHD), narcolepsy, and certain cases of obesity.
How Amphetamines Influence Brain Chemistry
Amphetamines exert their effects by altering the levels of specific neurotransmitters in the brain. They primarily target dopamine and norepinephrine, though they also have a lesser impact on serotonin. These drugs increase the concentration of these neurotransmitters in the synaptic cleft, the space between neurons where chemical signals are transmitted.
The mechanism involves amphetamine entering the presynaptic neuron, often through dopamine transporters (DAT) or norepinephrine transporters (NET). Once inside, amphetamine promotes the release of dopamine and norepinephrine from storage vesicles into the cytoplasm of the neuron. This displacement leads to higher levels of these neurotransmitters within the neuron itself.
Amphetamines cause the monoamine transporter proteins, like DAT and NET, to operate in reverse. This action facilitates the release of the increased cytoplasmic dopamine and norepinephrine into the synaptic cleft. Additionally, amphetamines inhibit the reuptake of these neurotransmitters by blocking their transporters, further prolonging their presence and activity in the synapse.
The heightened levels of dopamine are notable in the striatum, a brain region involved in motor control and reward processing, contributing to the pleasurable and reinforcing effects of amphetamines. Increased norepinephrine contributes to enhanced alertness and attention.
Immediate Bodily and Mental Responses
Shortly after amphetamine use, individuals experience a range of immediate bodily and mental changes. These effects can manifest rapidly, from immediately if injected or smoked, to within 30 minutes if snorted or swallowed. The onset and intensity of these responses can vary based on the specific type of amphetamine, the dose taken, and the individual’s physiology.
Physically, there is an increase in heart rate and blood pressure, which can place stress on the cardiovascular system. Pupils dilate, and individuals may experience reduced appetite. A surge of energy and wakefulness is common, along with enhanced physical performance and a delayed onset of fatigue.
Mentally and psychologically, amphetamines induce increased alertness, focus, and concentration. Users may report feelings of euphoria, happiness, and confidence, alongside increased talkativeness and a decreased sense of fatigue. However, these positive feelings can be accompanied by negative effects such as anxiety, irritability, restlessness, and insomnia.
These immediate effects are observed in both therapeutic and recreational contexts. In therapeutic use, such as for ADHD or narcolepsy, effects are controlled. Recreational use, however, involves higher doses, leading to more intense and unpredictable responses.
Chronic Health Consequences
Chronic amphetamine use can lead to serious long-term health consequences. One concern is the development of tolerance, where increasingly higher doses are needed to achieve the desired effects. This can progress to physical dependence and psychological addiction, making it challenging for individuals to stop using the drug without experiencing withdrawal symptoms.
The cardiovascular system is vulnerable to chronic amphetamine exposure. Sustained increases in heart rate and blood pressure can lead to chronic hypertension, irregular heart rhythms (arrhythmias), and damage to the heart muscle (cardiomyopathy). This elevates the risk of severe cardiovascular events, including heart attacks and strokes.
Neurological and psychiatric complications are prevalent with long-term use. Amphetamines can cause neurotoxicity, damaging brain cells, and altering brain structure and function over time. Individuals may develop persistent psychosis, characterized by hallucinations, delusions, and paranoia, which can resemble schizophrenia.
Beyond psychosis, chronic use is linked to severe depression, anxiety disorders, and cognitive impairment affecting memory and executive functions. Other physical effects include weight loss and malnutrition due to suppressed appetite. Dental problems can occur due to dry mouth and poor oral hygiene. Skin issues from picking are reported.