> "Although experiencing a hallucination might prompt confusion or fear, hypnagogic hallucinations are relatively common. Hypnagogic hallucinations are a common symptom of narcolepsy, but can also occur in people who do not have narcolepsy. In fact, one study found that 37% of people report experiencing hallucinations as they fall asleep."

Source: https://www.sleepfoundation.org/how-sleep-works/hypnagogic-h...

Their association with narcolepsy is one of several features, and it occurs more frequently and often during daytime naps in patients with narcolepsy:

> Hypnagogic states are not only an associated feature of narcolepsy, but they also are favourable for a diagnosis. Accordingly, the prevalence of hypnagogic states was higher in patients with narcolepsy than controls (Bosch et al., 2012; Fortuyn et al., 2009). Moreover, patients with narcolepsy are also more prone to experience daytime hypnagogia (Fortuyn et al., 2009), most likely due to excessive daytime sleepiness.

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC10078162/

It seems it's possible to get it from hypocretin deficiency via other routes like brain trauma, but they are confident enough to put this explanation in the DSM-5:

> Narcolepsy-cataplexy nearly always results from the loss of hypothalamic hypocretin (orexin)-producing cells, causing hypocretin deficiency (less than or equal to one-third of control values, or 110 pg/mL in most laboratories). Cell loss is likely autoimmune, and approximately 99% of affected individuals carry HLA-DQBl06:02 (vs. 12%-38% of control subjects). Thus, checking for the presence of DQB106:02 prior to a lumbar puncture for evaluation of CSF hypocretin-1 immunoreactivity may be useful.

https://ia800900.us.archive.org/0/items/info_munsha_DSM5/DSM...

pg 374, par 4 (pg 409 if using a PDF reader).

TL;DR: Narcolepsy is an autoimmune disorder caused by the destruction of the approximately 70,000 neurons that are responsible for producing the neurotransmitter orexin. [2]

A key piece of evidence was data analysis that showed a correlation between seasonal flu epidemic in China and subsequent new narcolepsy diagnoses. [1]

[1]: https://med.stanford.edu/news/all-news/2011/08/study-draws-c...

[2]: https://med.stanford.edu/news/all-news/2022/09/emmanuel-mign...

[3]: https://med.stanford.edu/content/dam/sm/narcolepsy/documents...

* Duloxetine (30mg, 2x daily)

My PCP prescribed the Duloxetine early in the process when they suspected I had ME/CFS. It did not seem to do much other than make me feel calm in situations that would normally cause anxiety, but later I got the IH diagnosis and was also prescribed Modafinil. My PCP offered to help me stop the Duloxetine, but I decided to stay on it because: 1) I was so grateful for the relative energy I had after starting the Modafinil that I didn't want to do anything to compromise that, and 2) I was enjoying the anxiety-reducing effect.

The Modafinil has not completely relieved symptoms; I still have fairly bad sleep inertia and will crash with a "sleep attack" about once a week, but that is far better than before, when I was sleeping 11-18 hours _every day_.

Sorry--I'm sure that's not too helpful to you, as it seems Modafinil is doctors' standard starting point for IH "treatment" (at least in the US).

Edit: Oh, and despite the "warnings" in the Modafinil instructions, I also drink about 3 cups of coffee a day (stopping at noon), and I feel that has been a vital supplement.

What has your experience been?

> just a more extreme case of the first is a complete inability to wake up.

> everything feels so exceptionally tired and heavy that I feel like I don't have the strength to move anything, even to turn my head.

I've tried to describe this feeling to others, but it's difficult. I call it my "death sleep," not to be dramatic, but because it's like waking from the deepest, most complete unconsciousness I can imagine. The heaviness in my body and chest make it feel a burden even to keep breathing; so I fall back asleep quickly.

After months of this, and visits with many specialists including a cardiologist, endocrinologist, and pulmonologist, an MSLT [1] gave the diagnosis of Idiopathic Hypersomnia [2, 3], which makes me laugh when you break it down: ("idio" = Unknown, "pathic" = Cause, "hyper" = Very, "somnia" = Sleep).

That diagnosis, while frustratingly vague, has at least allowed me to be prescribed medication that has made a big difference in my day-to-day alertness.

[1]: https://stanfordhealthcare.org/medical-conditions/sleep/narc... [2]: https://www.mayoclinic.org/diseases-conditions/hypersomnia/s... [3]: https://www.hypersomniafoundation.org/ih/