Selma Blair's candid "Good Morning America" interview about her multiple sclerosis diagnosis -- and the many years it took to receive the diagnosis -- has sparked an outpouring of praise and support.

Along with the support have come questions about multiple sclerosis (MS) and the different forms it takes in different people.

During her interview with "GMA" at her Los Angeles home, Blair, 46, was in an "exacerbation" of MS, or an attack that causes new symptoms or the worsening of existing symptoms. Her speech was also affected due to spasmodic dysphonia, a neurological disorder that affects the voice muscles in the larynx.

PHOTO: Actress Selma Blair opens up about her MS diagnosis in an interview with "GMA" co-anchor Robin Roberts.
Actress Selma Blair opens up about her MS diagnosis in an interview with "GMA" co-anchor Robin Roberts.

Despite her flare up, Blair, the mother of a 7-year-old son, still chose to speak out about MS in order to raise awareness of the chronic disease. She spoke about not only her physical challenges but also the mental challenges she faced as she went nearly seven years without a diagnosis.

"I had tears. They weren't tears of panic," Blair said about the moment last August that she was diagnosed. "They were tears of knowing I now had to give in to a body that had loss of control, and there was some relief in that."

The story shared by Blair, who used a bedazzled cane on Oscar night, encouraged others with MS to share their stories, too.

"Thank you for sharing Selma's story. I was diagnosed 19 years ago and I agree a positive attitude is so important," one woman wrote on Facebook. "It was over seven years before I was formally diagnosed."

"This diagnosis is devastating and a relief all at the same time," wrote another woman. "To know the whys of all my issues but be told there is no cure is hard. Thank you for bringing awareness to the foreground!"

Blair said her doctor has told her she could have 90 percent of her abilities back within a year.

"So this is to say, 'Let's meet again next year and see if I'm better,'" Blair told Robin Roberts. "If I'm not, and I can still have a conversation, that's good enough."

PHOTO: Actress Selma Blair opens up about her MS diagnosis in an interview with "GMA" co-anchor Robin Roberts.
Actress Selma Blair opens up about her MS diagnosis in an interview with "GMA" co-anchor Robin Roberts.

Read below for answers to common questions about MS.

What is MS and how do you get it?

MS is a chronic disorder in which cells from the immune system attack the nerve cells of the central nervous system (CNS). There's a special substance called myelin, which covers the nerve cells and allows messages to pass from your brain to the body and vice versa.

During a flare, the immune system attacks the myelin, the nerve covering becomes inflamed and communication between the brain and body is disrupted. The inflammation and nerve covering damage cause multiple areas of scarring (sclerosis) within the CNS, which is where the name "multiple sclerosis" originates.

Unfortunately, the cause of MS is not yet known. Scientists believe it could be caused by an unknown interaction of genetic predisposition and environmental factors.

Which part of the body is affected, and what are the symptoms?

Since the central nervous system is made up of your brain, spinal cord and specialized eye nerves, multiple sclerosis can affect a variety of body parts including arms, legs and eyes.

PHOTO: Signs and symptoms of MS.
Signs and symptoms of MS.

The most common problems are vision, balance and muscle control. Other symptoms include fatigue, numbness and tingling, weakness, dizziness, pain and emotional changes.

How is MS diagnosed?

There is not one definitive test to make an MS diagnosis, according to Dr. Jennifer Ashton, ABC News chief medical editor.

"When you talk about making a diagnosis, this is not like strep throat," she said. "What's required is two different episodes separated in time and location in our anatomy, in the central nervous system where there's been damage or flares."

PHOTO: Diagnosing MS.
Diagnosing MS.

Who is affected?

MS affects more women than men, which could be due to a protein, research shows.

Most people with MS are diagnosed between the ages of 20 and 50, with at least two to three times more women than men being diagnosed with the disease.

Researchers at the Washington University School of Medicine in St. Louis noticed in 2014 that a protein called S1PR2, which controls the permeability of the blood-brain barrier (BBB), is more prevalent in those with MS. Further research on both mice and humans revealed that, among people diagnosed with MS, women produced far more of this protein than men.

What is the treatment, and is there a cure?

There's currently no cure for MS. The specialists who treat MS are called neurologists. A neurologist will most likely use a combination of medications, physical therapy and psychiatric care to support patients following a diagnosis of MS.

"We have to do what's right for [the patient] over a long period of time, and the body often follows the mind and the spirit," Ashton said of the multidisciplinary approach to treating MS. "Your frame of mind and your attitude is so important, and often we get that from outside support."

The types of medications used are disease-modifying medicines, medicine to manage relapses and medicine to manage symptoms associated with a flare.

More of your questions answered

Watch the below video to hear more from Ashton about MS.

Dr. Colette Poole-Boykin,a child psychiatry fellow at Yale-New Haven Hospital and a former member of the ABC News Medical Unit, contributed to this report.