Medical Source Statements (MSS): What They Are and When You Need One

Key takeaways

• A medical source statement is one of the most helpful documents for your disability case. Written by your doctor, it explains how your condition affects your ability to work, like how long you can sit, stand, or lift which gives the SSA a clear picture of your limitations.

• Ask your doctor to complete a medical source statement. For best results, ask a doctor who you’ve been seeing for at least three months and who is familiar enough with your condition to write a strong statement. 

• Applying for disability benefits takes many steps and lots of paperwork, and most people are denied the first time. A lawyer can help at every stage, and at the hearing stage, claimants with a lawyer win benefits three times as often as those without.

When you apply for disability, the Social Security Administration (SSA) will talk to your doctors about your medical history. This helps the SSA understand the severity of your conditions and what kind of work you might be able to perform. One piece of paperwork you can submit to confirm your medical limitations is a medical source statement (MSS).

What is a Medical Source Statement?

A medical source statement (MSS) is a written document where your doctor shares:

• Their diagnosis of your condition

• Their opinion of its severity

• Their opinion on your ability to work because of your condition

The MSS will also talk about your treatments and your medical history. While this document isn’t required to apply for disability benefits, it can be helpful. You can submit as many statements as you’d like from providers who treat you — like your primary care physician, a specialist, or any other medical professional. But once a doctor fills one of these out, it is part of your medical record and Social Security has to receive a copy of it, so don’t ask a doctor if you don’t think they will be supportive. 

Remember, your doctor can’t put you on disability. To get disability benefits, you have to apply through the Social Security Administration (SSA). But your doctor can be a big help with certain parts of the process, such as submitting a medical source statement to help prove your condition is severe.

Who needs a Medical Source Statement?

A medical source statement (MSS) can help anyone whose doctor understands their condition and how it limits their ability to work. It can be especially helpful for:

• People under the age of 50. This is because it is often harder to qualify for disability than it is for people over 50.

• People applying with only a mental health condition. It's often harder to qualify for disability with only a mental health condition, especially if you're under 50. An MSS can help by showing how your condition affects things like focus, memory, or showing up to work reliably.

Who writes a Medical Source Statement and how to ask your doctor for one

You can get a medical source statement by asking your doctor to write one. For best results, ask a doctor who you’ve been seeing for at least three months — someone who is aware that you’re applying for disability. This ensures they’ll be familiar enough with your condition and your case to write a strong statement. Don’t ask a doctor for a Medical Source Statement if you don’t think they will be supportive. 

It also helps to check with your doctor's front desk, since some offices have their own process for these requests. Others may ask you to bring a form they can fill out, and your lawyer can usually provide one.

If you have a disability lawyer, they will talk to your doctor(s) and help you get statements. The SSA also might reach out to your doctor during the review process to ask for a medical statement. 

Medical Source Statement form and what it should include

There's no single required MSS form. What matters is that your doctor clearly explains your diagnosis and how your condition limits what you can do. 

Always include your formal diagnosis, the symptoms you experience, and how often they think you would miss work or be off task because of your disability. 

Mental health statements should document how your disability limits your ability to understand, remember, or apply information; interact with others; concentrate, persist, or maintain pace; and adapt or manage yourself. 

Physical health statements should include specifics like how much time you can spend sitting, standing, or walking in a work day; how much weight you can lift or carry both frequently and occasionally; and how much you can use your hands for gross and fine motor movement.

Make sure your doctor knows ahead of time that you’re applying for disability benefits. Whoever you decide to see for your MSS, continue seeing your doctor for several months. This will show the SSA you’re serious about getting treatment, but still aren’t better enough to work.

If you want your doctor to say something specific about your condition, make sure you’ve mentioned this to them before. Don’t ask them to add things they aren’t aware of.  Finally, this should go without saying — but never ask your doctor to lie for you (and don’t lie on your disability application). The information your doctor knows about you should be consistent with what you’ve said in your application, including in the function report.

Related: 7 Things You Shouldn’t Tell a Disability Doctor

Why a Medical Source Statement matters to your claim

A medical source statement is an important piece of documentation that helps prove your case — showing that you need disability benefits and explaining why. It serves as the bridge between your medical records and the legal criteria for disability.This statement is an opportunity to explain to the SSA how sick you are. So it’s essential for your MSS to be as strong as possible. 

After you submit an MSS, it goes into your file. Then it will be shared with any of the SSA’s medical examiners or judges that you see while continuing the application process. 

Where to get help with your disability claim

Applying for disability benefits takes many steps and lots of paperwork, including gathering medical evidence like a medical source statement. Most people are denied the first time. A disability lawyer can help at every stage, and at the hearing stage, claimants with a lawyer win benefits 3x as often as those without.

Talking to Atticus is free. We can help you understand whether you might qualify, and if you'd like, we can connect you with a disability lawyer. Take our free 2-minute quiz to get started.

The bottom line

A medical source statement shows that you need disability benefits and explains why. There isn't one specific MSS form for your doctor to fill out. Your doctor should write an MSS with all relevant information about your case. A disability lawyer can help you with your case and create a plan to get you benefits.