However, cocaine does not just induce short-term, pleasurable effects—chronic use can lead to dependence, addiction, and a number of changes in brain functioning. Unfortunately, people who are dependent on cocaine may experience withdrawal symptoms when they try to stop using, which can make quitting a very difficult undertaking.2 In many cases, withdrawal symptoms and strong cravings can be so problematic that people relapse, re-entering the cycle of cocaine addiction. In some cases, the acute cocaine withdrawal syndrome can be quite serious and may be associated with significant depressive symptoms and suicidal thoughts and attempts.2
Like many other addictive drugs, cocaine’s primary effects occur due to its action on neurotransmitters in the brain’s mesolimbic system, or reward pathway. Dopamine is one of the key neurotransmitters responsible for inducing feelings of reward and pleasure, as well as regulating emotional responses and motivation.6 Cocaine also acts on other important neurotransmitters, including serotonin (which regulates mood, among other vital processes) and norepinephrine (a primary stress chemical responsible for increased alertness and arousal).7
Your body makes these neurotransmitters as a way to maintain homeostasis and help you function optimally. Neurotransmitters are released by pre-synaptic neurons, then travel across the space between brain cells known as a synapse, and then bind to chemical-specific receptors, which are located on the ends of post-synaptic neurons. Neurotransmitters transmit messages across synapses to other brain cells. After transmission has occurred, a transporter removes the neurotransmitter from the synapse so it can be recycled and reused.6
However, cocaine interferes with this delicate communication system. When you use cocaine, it takes over and binds to the transporters for dopamine, serotonin, and norepinephrine; this prevents the reuptake (or recycling) of these chemicals and they accumulate in the synapse.5 Cocaine’s effects are largely due to dopamine accumulation in the synapse, which leads to the overstimulation of dopamine receptors. This is the main reason you experience feelings of euphoria after taking cocaine.6
This is also the primary reason that cocaine is so addictive—your brain is wired to repeat experiences that result in feelings of pleasure and reward, such as sex and eating. Repeated exposure to cocaine causes significant brain changes that underlie the eventual development of physiological dependence and addiction and dependence; over time, you may come to need cocaine to feel and function normally. Because repeated cocaine use results in a consistently elevated surge of dopamine activity, the body will eventually respond by downgrading the response elicited by the dopamine/receptor interaction and decreasing the number of dopamine receptors themselves.3 If you’re dependent and/or addicted and you stop taking cocaine, you subsequently experience withdrawal symptoms, such as depression, fatigue, and sleep disturbances.8 In order to avoid or alleviate these feelings, people often resume using cocaine.
When you use cocaine, it can cause immediate short-term brain changes that can impact a person’s mood and behaviors. The rate at which you will experience these effects and how long they last depends on the method of use. People who inject or smoke cocaine usually experience these effects immediately, because this provides the most rapid transmission of the drug to your brain. The high from injecting or smoking cocaine lasts just 5 or 10 minutes, while the high from snorting can come on more slowly but lasts between 15 and 30 minutes.9
Some of the short-term neurological effects of cocaine include:9
While these effects may only last a short while, people who abuse cocaine repeatedly may have an increased risk of incurring lasting changes to brain structure and function. This can ultimately lead to a number of problematic and debilitating neurological conditions that may be irreversible in certain cases.
As you continue using cocaine over time, your brain adjusts to the presence of the drug and makes a number of neuroadaptations, or changes. Not only does your brain become less sensitive to your natural reward chemicals, like dopamine, but your stress system also becomes increasingly sensitive. This can lead to a number of negative effects, such as irritability and bad moods, when you stop using cocaine.10
If you regularly use cocaine, you may develop tolerance to the desired effects; tolerance can increase your risk of overdose because you need to take more frequent or higher doses to achieve the same results.10 Tolerance develops as a result of neuroadaptation, which means that your brain has changed the way it responds to the drug; it is no longer as sensitive to certain cocaine effects as it once was. You can also simultaneously suffer from sensitization to some of cocaine’s adverse effects, which means that you actually require less cocaine to produce negative or troubling symptoms, such as anxiety, convulsions, and other toxic effects.
Over time, you can develop dependence, at which point, you will need to continue using cocaine in order to feel normal. If you are dependent, you suffer from withdrawal symptoms when you don’t use. Dependence and continued cocaine abuse can eventually lead to addiction, a chronic, relapsing condition in which you continue abusing the drug despite knowledge of the negative consequences to your health and overall well being.2
Cocaine can cause a number of troublesome and lasting neuroadaptations. In addition to its effects on dopamine, studies on animals have shown that cocaine may cause significant changes to brain cells that release an excitatory neurotransmitter within the brain’s reward pathway called glutamate. These changes to glutamatergic neurotransmission could additionally contribute to the reinforcing effects of cocaine.11
Long-term cocaine abuse can have a range of additional harmful effects on the brain, including:11-14,18
Researchers are in the process of examining specific antidotes that may prevent cocaine’s damage to the brain, but more studies are needed to fully confirm their effects and safety.15In some cases, quitting cocaine may help to prevent or reverse some of these brain effects, but research in this area is still ongoing. Studies using fMRI technology have found that “abstinence has important, restorative effects on the brain.”16
For example, researchers found that former cocaine users who abstained for 8 months displayed similar patterns of brain activation and performance when compared to people who never used the stimulant drug.16 Additionally, a clinical review reports that there is evidence that some of the structural brain changes associated with chronic cocaine abuse may be reversible with abstinence.17