NNLM Network of the National Library of Medicine

What is addiction?

For much of the past century, scientists studying drugs and drug use labored in the shadows of powerful myths and misconceptions about the nature of addiction. When scientists began to study addictive behavior in the 1930s, people with an addiction were thought to be morally flawed and lacking in willpower. Those views shaped society’s responses to drug use, treating it as a moral failing rather than a health problem, which led to an emphasis on punishment rather than prevention and treatment.

• Learn more from the National Institute on Drug Abuse

What is autism spectrum disorder?

Autism spectrum disorder (ASD) is a neurological and developmental disorder that begins early in childhood and lasts throughout a person's life. It affects how a person acts and interacts with others, communicates, and learns. It includes what used to be known as Asperger syndrome and pervasive developmental disorders.

It is called a "spectrum" disorder because people with ASD can have a range of symptoms. People with ASD might have problems talking with you, or they might not look you in the eye when you talk to them. They may also have restricted interests and repetitive behaviors. They may spend a lot of time putting things in order, or they may say the same sentence again and again. They may often seem to be in their "own world."

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April is Autism Acceptance Month

What is testicular cancer?

Testicles, or testes, make male hormones and sperm. They are two egg-shaped organs inside the scrotum, the loose sac of skin behind the penis. You can get cancer in one or both testicles.

Testicular cancer mainly affects young men between the ages of 20 and 39. It is also more common in men who:

• Have had abnormal testicle development
• Have had an undescended testicle
• Have a family history of the cancer

Symptoms include pain, swelling, or lumps in your testicles or groin area. Doctors use a physical exam, lab tests, imaging tests, and a biopsy to diagnose testicular cancer. Most cases can be treated, especially if found early. Treatment options include surgery, radiation, and/or chemotherapy. Regular exams after treatment are important.

• Learn more from MedlinePlus

What is diabetes?

Diabetes is a disease in which your blood glucose, or blood sugar, levels are too high. Glucose comes from the foods you eat. Insulin is a hormone that helps the glucose get into your cells to give them energy. With type 1 diabetes, your body does not make insulin. With type 2 diabetes, the more common type, your body does not make or use insulin well. Without enough insulin, the glucose stays in your blood. You can also have prediabetes. This means that your blood sugar is higher than normal but not high enough to be called diabetes. Having prediabetes puts you at a higher risk of getting type 2 diabetes.

Over time, having too much glucose in your blood can cause serious problems. It can damage your eyes, kidneys, and nerves. Diabetes can also cause heart disease, stroke and even the need to remove a limb. Pregnant women can also get diabetes, called gestational diabetes.

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What is heartburn?

Heartburn is a painful burning feeling in your chest or throat. It happens when stomach acid backs up into your esophagus, the tube that carries food from your mouth to your stomach.

If you have heartburn more than twice a week, you may have GERD. But you can have GERD without having heartburn.

Pregnancy, certain foods, alcohol, and some medications can bring on heartburn. Treating heartburn is important because over time reflux can damage the esophagus.

Over-the-counter medicines may help. If the heartburn continues, you may need prescription medicines or surgery.

If you have other symptoms such as crushing chest pain, it could be a heart attack. Get help immediately.

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What is obesity?

Obesity means having too much body fat. It is different from being overweight, which means weighing too much. The weight may come from muscle, bone, fat, and/or body water. Both terms mean that a person's weight is greater than what's considered healthy for his or her height.

Obesity happens over time when you eat more calories than you use. The balance between calories-in and calories-out differs for each person. Factors that might affect your weight include your genetic makeup, overeating, eating high-fat foods, and not being physically active.

Obesity increases your risk of diabetes, heart disease, stroke, arthritis, and some cancers. If you have obesity, losing even 5 to 10% of your weight can delay or prevent some of these diseases. For example, that means losing 10 to 20 pounds if you weigh 200 pounds.

• Learn more from MedlinePlus