Sexually transmitted diseases (STDs) are caused by sexually transmitted infections (STIs). They are spread mainly by sexual contact. STIs are caused by bacteria, viruses or parasites. A sexually transmitted infection may pass from person to person in blood, semen, or vaginal and other bodily fluids.

Sometimes sexually transmitted infections are spread in ways other than sexual contact. For example, STIs can spread to infants during pregnancy or childbirth. STIs also can spread through blood transfusions or shared needles.

STIs don’t always cause symptoms. A person can get sexually transmitted infections from another person who seems healthy and may not even know they have an infection.

Acquired immunodeficiency syndrome (AIDS), is an ongoing, also called chronic, condition. It’s caused by the human immunodeficiency virus, also called HIV. HIV damages the immune system so that the body is less able to fight infection and disease. If HIV isn’t treated, it can take years before it weakens the immune system enough to become AIDS. Thanks to treatment, most people in the U.S. don’t get AIDS.

HIV is spread through contact with genitals, such as during sex without a condom. This type of infection is called a sexually transmitted infection, also called an STI. HIV also is spread through contact with blood, such as when people share needles or syringes. It is also possible for a person with untreated HIV to spread the virus to a child during pregnancy, childbirth or breastfeeding.

There’s no cure for HIV/AIDS. But medicines can control the infection and keep the disease from getting worse. Antiviral treatments for HIV have reduced AIDS deaths around the world.

Hepatitis C is a viral infection that primarily affects the liver, causing inflammation and potentially leading to serious liver damage. It is transmitted through blood-to-blood contact, such as sharing needles or through certain sexual activities. New antiviral treatments are available, and more than 95% of people with Hepatitis C can be cured with oral medications. Without treatment, the infection can lead to severe liver disease. If you suspect you have Hepatitis C or are at risk, it is important to seek medical advice for testing and treatment options.

AUD (Alcohol use disorder) is characterized by an impaired ability to stop or control alcohol use despite adverse social, occupational, or health consequences. Health care providers diagnose AUD when a person has two or more of the symptoms listed below. AUD can be mild (the presence of two to three symptoms), moderate (the presence of four to five symptoms), or severe (the presence of six or more symptoms).

In the past year, have you:

• Had times when you ended up drinking more, or longerthan you intended?
• More than once wanted to cut down or stop drinking, or tried to, but couldn’t?
• Spent a lot of timedrinking, being sick from drinking, or getting over other aftereffects?
• Wanted a drinkso badly you couldn’t think of anything else?
• Found that drinking—or being sick from drinking—often interfered with taking careof your home or family? Or caused job troubles? Or school problems?
• Continued to drink even though it was causing troublewith your family or friends?
• Given up or cut back on activitiesyou found important, interesting, or pleasurable so you could drink?
• More than once gotten into situations while or after drinking that increased your chances of getting hurt (such as driving, swimming, using machinery, walking in a dangerous area, or engaging in unsafe sexual behavior)?
• Continued to drink even though it was making you feel depressed or anxiousor adding to another health problem? Or after having had an alcohol-related memory blackout?
• Needed to drink much morethan you once did to get the effect you want? Or found that your usual number of drinks had much less effect than before?
• Found that when the effects of alcohol were wearing off, you had withdrawal symptoms, such as trouble sleeping, shakiness, restlessness, nausea, sweating, a racing heart, dysphoria (feeling uneasy or unhappy), malaise (general sense of being unwell), feeling low, or a seizure? Or sensed things that were not there?

If you have any of these symptoms, alcohol may already be a cause for concern. The more symptoms you have, the more urgent the need for change. A health care provider can look at the number, pattern, and severity of symptoms to see whether AUD is present and help you decide the best course of action.

A Substance Use Disorder (SUD) is a medical condition that is defined by the inability to control the use of a particular substance (or substances) despite harmful consequences.¹ In other words, SUDs occur when an individual compulsively misuses drugs or alcohol and continues using the substance despite knowing the negative impact it has on their life.^2,3 

SUDs may range from mild to severe, with severity depending on the number of diagnostic criteria a person meets. When someone is diagnosed with mild SUD, this means a person displays 2-3 symptoms, moderate means they display 4-5 symptoms, and severe means they display 6 or more.²

The American Psychiatric Association (APA) has developed 11 criteria for SUD diagnosis in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).²

The DSM-5 Criteria for Substance Use Disorders includes:²

• Taking the substance for long periods of time or in larger amounts than intended.
• Being unable to cut down or stop substance use.
• Spending a lot of time obtaining, using, and recovering from the effects of the substance.
• Experiencing cravings, or intense desires or urges for the substance.
• Failing to fulfill obligations at home, work, or school due to substance use.
• Continuing substance use despite having interpersonal or social problems that are caused or worsened by substance use.
• Giving up social, recreational, or occupational activities due to substance use.
• Using the substance in risky or dangerous situations.
• Continuing substance use despite having a physical or mental problem that is probably due to substance use.
• Tolerance, or needing more of the substance to achieve previous effects.
• Withdrawal, meaning that unpleasant symptoms occur when you stop using your substance of choice.

Substance Use Disorder Statistics

The National Survey on Drug Use and Health (NSDUH) provides statistics on substance use and substance use disorders across the US. The most recent NSDUH (2019) results show the prevalence of SUDs in general and specific types of the following: SUDs in the US in people aged 12 and older over the previous year.

• 4 million people had an SUD.⁴ 
• 5 million had an alcohol use disorder.⁴
• 6 million had a marijuana use disorder.⁴
• 1 million had a cocaine use disorder.⁴
• 438,000 had a heroin use disorder.⁴
• 1 million had a methamphetamine use disorder.⁴
• 558,000 had a prescription stimulant use disorder.⁴
• 681,000 had a prescription tranquilizer or sedative use disorder.⁴
• 4 million had a prescription pain reliever disorder.⁴
• 6 million had an opioid use disorder.⁴

A rehab center is a clinic that provides rehabilitation services, medical treatment, and psychiatric care to assist individuals in identifying the root cause of their addiction, addressing underlying mental health issues, and working on coping with withdrawal symptoms to achieve recovery through prolonged sobriety.