What Is a Medical Source Statement?

A Medical Source Statement is a report completed by your healthcare provider that outlines:

• Your official diagnosis and prognosis
• Functional limitations, such as lifting, walking, sitting, standing, concentration, memory, and fatigue
• Frequency and duration of symptoms
• Environmental and workplace restrictions (e.g., no exposure to bright light, ability to sit only 20 minutes at a time)

This document helps the Social Security Administration (SSA) understand how your medical condition affects your daily life and work potential.

Who Should Provide the MSS?

To be most effective, your medical source statement should come from:

• A treating physician you see regularly
• A specialist who manages your condition (e.g. neurologist, rheumatologist, psychiatrist)
• A licensed clinical psychologist or psychiatrist for mental health conditions
• A physical or occupational therapist, in some cases, to describe functional capacity assessments

Statements from providers who have a long-term treating relationship with you carry more weight than those from providers who have only seen you once.

How to Request a Medical Source Statement

1. Talk to Your Provider Directly

Explain that you’re applying or appealing SSDI and ask if they can complete an MSS. Be clear that the form should include precise detail about your limitations and functional capacity.

2. Provide a Template or Example

SSA provides sample MSS formats that physicians can use. Some providers prefer to fill out their own version. Offer them a copy to ensure all needed areas are addressed.

3. Schedule a Specific Visit

If your provider hasn't previously documented specific limitations, request a medical appointment focused on functional assessment so the MSS is based on current, documented observation.

4. Be Clear and Professional

Bring relevant medical records, recent treatment notes, test results, and a symptom diary. This gives your provider accurate information to reference when writing the statement.

What to Include in the Form

Make sure the statement covers:

• How long you've been treated and follow‑up care
• Specific symptoms and how they affect your functioning (e.g., “can only walk half a block before resting”)
• Limitations in work-related activities (e.g., sitting no more than 10 minutes, cannot lift more than 10 pounds)
• Frequency of episodes (e.g., “symptoms flare 4–5 days per month”)
• Effects of medication or fatigue on performance and attendance

What If Your Provider Refuses?

If your provider is unwilling to complete an MSS:

• Explain how important it is for your SSDI case
• Offer to pay a small administrative fee if allowed
• Ask if another member of the care team (e.g., PA or NP) can sign
• Request a functional assessment note instead, which details your limitations in regular records

If strong documentation still isn’t possible, Medicaid, clinics, or legal advocates may help connect you to providers willing to assist.

Why an MSS Matters in SSDI Claims

An MSS gives the SSA concrete, physician-introduced limitations to compare against their medical listings. When a condition doesn’t neatly match a SSA-defined listing, an MSS can bridge the gap by showing that your symptoms are functionally equivalent. It’s especially helpful in appeals or hearings where SSA experts evaluate your case closely.