Differential Diagnostics
Tweeze apart competing conditions to get at their cause.
Please note that the information provided on our website is intended for educational and informational purposes only. It is not a substitute for professional advice or treatment. If you require immediate assistance or are in crisis, please reach out to a qualified mental health professional or helpline in your region.
Gray Thorn has created a spreadsheet that you can adapt to your body. You can get an introduction to how it works here. Support their work here.
Hypersomnia (Oversleeping)
Sleepiness - The tendency to fall asleep
Fatigue - Lacking energy
Possible explanations for hypersomnia, and how to tell if you need strategies for obtaining more of it (protect the hypersomnia), or less of it (reject).
Medical Issues (Seek Treatment from Specialist)
Some clues that point more toward medical causes:
- No matter how much sleep you get you don’t feel refreshed
- Sudden change from previous baseline
- Possible Sleep Apnea → Somnologist; snoring, gasping, dry mouth, headaches
- Possible Thyroid Issues → Endocrinologist; cold intolerance, weight changes, hair thinning
- Possible Anemia → Family Doctor/GP or Hematologist; Dizziness, paleness, shortness of breath
- Possible Systemic Illness → Family Doctor/GP ideally coordinates a team of specialists working together; Body pain, fevers, swollen joints, post-exertional crashes
If the sleep increase is:
- Sudden
- Worsening
- Impairing daily life
- Accompanied by physical symptoms
- And/or impossible to resist
It is worth ruling out medical causes first because conditions like anemia, thyroid disorders, sleep apnea, and deficiencies are common and treatable. If you live in a region with public healthcare, make sure you get on a waitlist first even if you don’t think you’ll need it.
If it is impairing daily life and you can’t afford to rest but you do have access to affordable care, a medical doctor may be able to prescribe solutions or refer you to someone who can help with a transition.
Physical symptoms can still be a signal of the following (see below).
Sleep Debt or Burnout (Protect)
Sleep gets longer after stressful periods, deadlines, masking, travel, social overload, etc. After several days or weeks of rest, sleep gradually decreases if there is sleep debt. In the case of burnout it can take months to a year.
The person usually can wake up if absolutely necessary for survival, even if they dislike it. Energy improves noticeably with reduced demands.
Depression (Reject)
Sleep often feels “heavy” rather than restorative. There may be loss of interest, emotional numbness, guilt, hopelessness, slowed thinking, or withdrawal. The person may stay in bed even when not fully asleep.
Fatigue is often psychological and physical.
Fatigue/Recovery Associated with Neurodivergence (Protect + Lifestyle Change)
Long sleep tends to follow intense sensory, social, or executive-function effort. The person may function well in areas they care about but crash afterward.
Rest helps, but demands rapidly consume energy again. There may be a lifelong pattern of needing more recovery than peers. You need to design your life differently to accommodate crashes.
Circadian Rhythm (Lifestyle Changes)
You sleep normally if allowed to follow your own schedule. Problems mainly appear when forced into conventional schedules, which can dysregulate someone into something that looks like hypersomnia. Cicadian rhythms change overtime.
Naturally sleeping 3am–1pm and feeling fine.
How to Tell
- “Do I feel refreshed after 12 hours?”
- “Has this always been true?”
- “What happens if my stress decreases?”
- “Do I feel sleepy, or just exhausted?”
- “Am I physically tired, mentally tired, emotionally shut down, or all three?”
- “What events reliably trigger the long sleep?”
- “Do I crash after socializing or work?”
- “Has my body or life circumnstances changed recently?”