A drug is essentially any substance, save for food and water, that, when ingested, can alter the way the body functions, be it physically or psychologically. Drugs may either be legal, i.e. over the counter (such as alcohol, tobacco, caffeine), prescription i.e. they require a doctors authorization (such as Adderall) or illicit/illegal, such as heroin.
Drugs mainly work by reaching your brain and disrupting the natural chemical messaging system in order to create the desired effect. The more often a drug is used, the more impact it has on the brains chemicals and circuitry which ultimately leads to drug dependence and withdrawal symptoms when the drug is processed out of the body. This, coupled with drug cravings and loss of control over use are generally signs of addiction.
The exact mechanisms of how a drug works can be lengthy and complicated, however, below are a list of drugs with a brief explanation of how they work and affect the brain in order to create a basic understanding:
Cannabis is the active substance in the hemp plant used for marijuana. The psychoactive chemical in marijuana tetrahydrocannabinol (THC), interacts and binds with the cannabinoid receptors in the braid to produce a euphoric, mellowing feeling and enhanced sensory perception while also increasing your heart rate, creating a lack of focus and short term memory loss.
This is due to the fact that the hippocampus, which is responsible for managing short term memory, also has a high concentration of cannabinoid receptors and so is heavily impacted.
Marijuana also interferes with the dopamine levels (reward center) of the brain which is also responsible for the “high” feeling. Marijuana also has some long term effects which are especially prevalent in individuals who use the drug before their brains have fully developed. This is mainly in the case when its use begins in adolescence and continues into adulthood.
Heroin and Prescription Opioids
Heroin and prescription opioid drugs(such as Oxycodone and acetaminophen/hydrocodone) are made from Opium Poppy and were developed to serve as pain relievers. They do this by binding to certain receptor cells in the nervous system and brain.
By occupying the same receptors, the naturally occurring pain messages are unable to get through and the opioids also begin to send their own signals through the receptors to flood the brain the dopamine. This again essentially hijacks the reward center of the brain and accelerates addiction.
Opioid drugs also disrupt the natural production of norepinephrine and act as a central nervous system depressant. Long term and chronic heroin use can lead to a general deterioration of the brains white matter which negatively affects how a person responds to stress, regulates emotions or makes decisions.
Cocaine, Methamphetamine and other Stimulants
The actual medical use for stimulants has shifted in recent years as historically they were prescribed to treat certain neurological disorders, asthma and even obesity. However, due to the increasing concern for the addictiveness of the drugs, its use has been limited to attention deficit disorder, depression and narcolepsy.
Stimulant drugs speed up the central nervous system while increasing energy levels, focus, attention and wakefulness. It however decreases ones appetite. Meth and cocaine, like most other illicit drugs, simply take over the reward system of the brain and flood it with dopamine.
This produces an extremely intense but fleeting high, which results in abuse of the drug in order to lengthen the feeling of euphoria. Due to this, stimulants are extremely addictive. Meth abusers may suffer from hallucinations and anxiety and significantly damages the dopamine system of the brain and thus causes problems with memory and learning.
Known more commonly by its street name “molly”, ecstasy is a psychoactive drug that is mostly popular in clubs. MDMA(ecstasy) attaches to serotonin transporters in the brain and has characteristics of both stimulants and hallucinogens.
It stimulates the activity of serotonin, dopamine and norepinephrine enhancing and distorting the senses and heightening energy levels. It also affects the way the brain processes and stores information and memories. It can also be psychologically addictive causing withdrawal symptoms when the drug is not taken.
LCD, PCP, Ketamine and other Hallucinogens
Hallucinogens are so aptly named due to the fact that they cause the user to see hallucinations, i.e. distortions of perception and reality. They are believed to interrupt the normal communication between neurotransmitters and also disrupt the action of glutamate. This is a brain chemical that plays a role in memories, perception of pain, cognition, and emotions.
Some hallucinogens interact with dopamine while others activate the kappa opioid receptors on nerve cells. This allows the user to separate themselves from their environment and reality. However, classic hallucinogens, such as LCD and peyote, interact mainly with serotonin and the prefrontal cortex of the brain. This is essentially results in a drug induced psychosis, or “trip”. This trip can range from a spiritual awakening to feelings of panic, paranoia, anxiety and despair.