A wide range of drugs are potentially addictive. While not everyone who takes these addictive substances becomes psychologically dependent on them, owing to the numerous factors that influence susceptibility to addiction, anyone who uses them in the longer term is potentially at risk. It is not just illicit drugs like cocaine, heroin and methamphetamine that are addictive though, as various prescription medications, such as painkillers and tranquilizers, also have addiction potential. Addiction is able to develop owing to the impact that all these substances have on the reward pathway in your brain. Addictive substances increase levels of dopamine through a variety of mechanisms, which leads to feelings of pleasure and encourages you to continue taking the drug. With repeated exposure you also need to take higher doses of a substance to get the same feel-good response, which contributes to the development of addiction. Over time, changes in your brain occur that further reinforce drug taking owing to the way that they enhance cravings and make you lose control of your habit.

It is a common misconception that prescription drugs are safer than illicit substances, as all types of drugs have the potential to cause harm and are not necessarily any less addictive; this is demonstrated by prescription opiates like codeine and oxycodone, which have similar adverse effects and addiction potential to heroin. As a result, prescription medication abuse is common, particularly among high school and college students who can easily access them from family and friends who have a genuine need for the drug. Although prescription drugs are legal when you have instruction from a doctor, either taking or supplying these medicines otherwise is against the law.

Illegal Drugs List

Although the number of illicit drugs is growing, as new synthetic drugs are developed, the followingillegal drug list shows those that are most commonly abused:

• Marijuana. More people abuse cannabis than any other drug. While many use it infrequently for recreational purposes, it is still potentially addictive when used regularly and in the longer term. Currently, medical use of marijuana is legal in around 20 states, though marijuana use for non-medical purposes is only legal in Colorado and Washington at present.
• Heroin. While less than 700,000 Americans used heroin at any point during 2012, the drug is highly addictive, bringing a range of serious health and social consequences with its heavy use. Rates of HIV and hepatitis are high among IV heroin addicts and the tolerance that develops with repeated use increases the risk of a fatal heroin overdose. An addiction to heroin also makes it difficult to stay in employment and users are more likely to spend time in jail, both of which can take their toll on family life.
• Cocaine. As a stimulant cocaine offers a rush and a burst of energy, but can also lead to a potentially fatal heart attack, even in previously healthy users. Once you become reliant on the high that cocaine provides, it is common to take the drug repeatedly in quick succession and higher doses to sustain these feelings, which not only increases the risk of adverse effects, but also the risk of addiction. As smoking or injecting crack produces more intense effects than snorting coke, these methods of taking cocaine can also increase the rate at which addiction develops.
• Crystal meth. An addiction to methamphetamine can develop quickly, as while taking the drug offers an intense high, the comedown leads to unpleasant feelings such as low mood and anxiety, so users take the drug frequently to avoid feeling this way. With heavy use of meth, complications soon develop, with malnutrition, meth mouth, skin scarring, paranoia and psychosis all common.
• Amphetamines. These kinds of drugs are similar to crystal meth, so are highly addictive and their use leads to a range of harmful physical and mental health problem. Even if you take amphetamines to aid weight loss or to give you an energy boost to get you through long days or enhance your sporting performance, you can easily develop an addiction, in the same way that someone who takes them to achieve a buzz can get addicted to amphetamines.
• Ecstasy. While this party drug is often taken infrequently, heavy users risk addiction to ecstasy. Research shows that among young ecstasy users, more than 40% are dependent on the drug and more than 30% show signs of addiction. As with other drug users, it is also common for ecstasy users to have an addiction to other drugs or alcohol.
• LSD. Although it is uncommon to develop a physical dependence on LSD, psychological dependence can easily develop among regular users. In these instances the drug becomes the focus of their lives, so they feel unable to function without it and feelings of anxiety and panic are common if they do not have a supply of the drug.
• GHB. Even though taking GHB can offer feelings of happiness and give you extra energy, in higher doses it can produce serious adverse reactions and is potentially fatal. If tolerance develops, these risks increase, and contrary to popular belief, the drug is addictive. However, physical rather than psychological addiction is more likely.

Prescription Drugs List

While any of these substances could join the list of illegal drugs when abused, it is possible to develop an addiction to these drugs if your prescription use is not adequately monitored:

• Opiates. These prescription painkillers give you a high, so it is not surprising that they are highly addictive. Even if you take them to manage legitimate pain, you can find yourself continuing to use them even once the pain subsides and you will go out of your way to obtain additional prescriptions. When taking increasing doses to overcome drug tolerance, your risk of an overdose rises, with opioid painkillers responsible for almost three-quarters of all pharmaceutical overdose deaths.
• Anabolic steroids. While anabolic steroids are sometimes prescribed to manage muscle wasting conditions and hormonal problems that affect men, they are often abused by men and women who want to bulk up, whether to improve their physique or to improve their performance in sport. They not only interfere with hormone levels, but also increase the likelihood of heart, kidney and liver disease. Even without giving you a high, taking anabolic steroids places you at risk of addiction, with users continuing to abuse these drugs long after they start causing health and social problems.
• Sedatives. Sleep medications like zolpidem not only aid sleep, but can also enhance your mood, promote relaxation and lower your inhibitions, which make them an attractive drug for anyone looking for help with these areas. However, as tolerance quickly develops, this makes it easier for an addiction to develop and even people who genuinely need these medications to sleep find that they struggle to withdraw from them.
• Tranquilizers. Around 2% of the US population abuse these type of drugs that are prescribed to relieve anxiety. Benzodiazepines, such as Ativan and Valium, should only be prescribed for short periods though due to their addictive nature. If taken for more than a few weeks, you are likely to feel more anxious when you come off the drugs and experience a range of psychological and physical withdrawal symptoms.
• ADHD stimulants. While ADHD medication is only prescribed to treat the symptoms of ADHD and narcolepsy, these different kinds of drugs are a favorite among students, as there is a belief they can boost academic performance, give you more energy and help with weight loss. However, as ADHD drugs are based on amphetamines, they have a high addiction potential, so it is easy for occasional use to become problem drug use.