Although each drug causes unique physiological and neurological effects, all drugs overlap in one important way, said Dr. Scott Krakower, assistant unit chief for psychiatry at Zucker Hillside Hospital, New Hyde Park in New York. All drugs cause changes in the brain, some in ways that may be long-lasting or even permanent.
These brain changes can have significant effects on mood and cause depression, ultimately lessening a person's ability to lead their best and healthiest life.
Your brain regulates all the body's basic functions, including every breath and each heartbeat, while enabling you to interpret and respond to experience. It shapes thoughts and emotions and determines your behavior.
Despite some commonality, the short- and long-term health effects of drugs are distinct, with each one potentially affecting life spans in a different way.
Opioids include heroin
and prescription pain relievers such as oxycodone, hydrocodone, codeine, morphine and fentanyl. All members of the same chemical family, these drugs interact with the opioid receptors on nerve cells in both the body and the brain.
Though opioids bring a reduction in pain, these drugs also cause changes in your blood pressure, in terms of lowering it acutely, and can bring changes in heart rhythm.
An opioid user's blood pressure can drop suddenly and significantly, "and that can lead to a stroke," said Dr. Robin Dharia, a vascular neurologist at Lenox Hill Hospital in New York. She added that opiates affect breathing and oxygenation of blood. With overdoses, users have difficulty breathing, which can be deadly.
In the long term, "opiates can have a lot of effects on the body. Most commonly, we think of problems with bowel function," Dharia said. Nausea and vomiting are common among users, while some have trouble going to the bathroom. If this constipation becomes severe enough, it can lead to an intestinal rupture, she said.
"Opiates can also cause problems with the endocrine system -- your hormone system," Dharia said, which can lead to problems with sexual function, fertility and reduced testosterone levels in men. Bone disorders may also be a result of chronic use.
"Chronic use can cause slowing of the electrical activity in the brain," Dharia said, explaining that because opiates depress the central nervous system, they can cause sleep-wake cycle changes, mood changes, cognitive issues and even cognitive decline.
"We see seizures after abrupt changes in opiate use," Dharia said.
Physiologically, cocaine reduces blood flow in the gastrointestinal tract, which can lead to tears and ulcerations. Chronic cocaine users often lose their appetite and may become malnourished. Cocaine
also has well-recognized negative effects on the heart and cardiovascular system.
This drug can "damage and destroy the walls of the heart," Dharia said, and it can affect the coronary arteries. "Even in young people without the typical risk factors, it can narrow the arteries in the heart," she added.
Chest pains resembling a heart attack send many users to the ER. Meanwhile, long-term medical consequences include cardiac conditions, such as deterioration of the heart's ability to contract, and aortic ruptures as well as neurological impairment, said Krakower.
Bleeding in the brain and bulges in the walls of blood vessels in the brain also accompany long-term cocaine use.
"You can get a stroke after your first try or years of use," Dharia said, adding that cocaine causes "quite a bit of damage to the arteries in the brain," which sometimes causes seizures.
Movement disorders, including Parkinson's disease, may also occur after many years of use. Meanwhile, in the brain, the reward pathway becomes less sensitive, while brain circuits involved in stress become increasingly sensitive.
"Because you have this dramatic change in dopamine, you might not be able to feel ... sensation or pleasure," Krakower said. "Long-term effects from cocaine include interference within the glutamate system and prefrontal cortex."
The result of these brain changes means regular cocaine users are more likely to want, seek and use the drug instead of focusing on relationships, food or other natural rewards.
"The idea is, you can get this lack of motivation and sort of blah feeling and not have the same, let's say, reaction to things -- even libido," Krakower said.
Cocaine worsens memory, according to Krakower. In addition, studies suggest that long-term cocaine use harms a range of cognitive functions, including making decisions, performing motor tasks, sustaining attention and inhibiting impulses.
Marijuana and hallucinogens
is the "most commonly used illicit drug in the United States," the National Institute on Drug Abuse says. Weed produces euphoria, yet it also impairs the judgment of users, motor coordination and reaction times. Short-term, cannabis increases the heart rate, even doubling it in some cases. Sudden rapid beating poses a cardiac danger to anyone with a pre-existing heart condition.
Marijuana contains toxic gases and particles that can harm the lungs. Routine smoking is linked to airway inflammation and increased symptoms of chronic bronchitis. Regular users have a greater likelihood of respiratory infections, including pneumonia.
A few studies have shown that marijuana use in the teen years is associated with an increased risk for an aggressive form of testicular cancer. National Institute on Drug Abuse researchers say early onset of this cancer indicates that just a few years of use may be harmful.
Different still are hallucinogens, such as lysergic acid diethylamide (LSD), or acid; mescaline and peyote; psilocybin, or "magic mushrooms"; and phencyclidine (PCP), or angel dust.
Generally, hallucinogens distort a user's perception of reality, direction, distance and time. Some have effects lasting up to 12 hours. Disoriented, users can become unpredictable, erratic and violent, which can lead to serious injury or even death.
With LSD, in particular, repeat users develop a tolerance, so they tend to take higher and higher doses to achieve the same psychedelic effects. Large doses of LSD are more likely to cause convulsions, coma, heart and lung failure, or death.
Counteracting the harm done
If you've used drugs, you might want to take certain countermeasures. The first one is quitting.
"Though you have used them or tried them in the past, the idea is that if you stop, while some things may be permanent -- the idea is hopefully, our bodies can learn to compensate and move forward the best it can," Krakower said. "Therefore, you want to try and stop earlier rather than later."
Dharia agrees: "Quitting is the first step."
After that, she said, former drug users need to make sure they see their primary care physicians on a regular basis and "be honest" about their history, because "any physician will understand the potential long-term effects of those drugs and what to screen for."
Along with routine doctor visits, former drug users need to exercise regularly, never smoke, avoid excessive alcohol, watch their sugar and eat healthy, said Dharia: "That's everything you can do afterward."