Sex differences in narcolepsy type 1 vary with age and timing of onset

Sex-related differences in clinical manifestations, sleep characteristics, and symptom evolution in narcolepsy type 1 (NT1) appear to vary with age and timing of disease onset, according to a large study in China.

Among people whose NT1 began in adulthood, women waited substantially longer for a diagnosis than men, while men were more likely to have sleep apnea, or repeated pauses in breathing during sleep, and had different sleep patterns than women.

But sex differences were less apparent when NT1 began earlier in life. Among children with NT1, key symptoms and time to diagnosis were largely similar between girls and boys. Among adults whose NT1 had begun during childhood, many of the sex differences seen in people with adult-onset disease were no longer apparent.

Recommended Reading

Aug. 20, 2026 News by Margarida Maia, PhD

Analysis finds meaningful attention gains with narcolepsy therapy

Symptoms change differently over time in males and females

Differences also emerged in how symptoms changed over time. Among untreated participants, cataplexy frequency — how often sudden episodes of muscle weakness occurred — and daytime sleepiness scores decreased significantly from diagnosis to follow-up in males, but not females.

“Sex associates with NT1 features differently in children and adults,” the researchers wrote, adding that “prospective longitudinal studies are warranted to clarify sex-specific disease progression and optimize management strategies for NT1.”

The study, “Sex Differences in Patients with Narcolepsy Type 1: Clinical Manifestations, Sleep Profiles, and Symptoms Evolution,” was published in Sleep Medicine.

Narcolepsy is a sleep disorder marked by symptoms such as excessive daytime sleepiness and disrupted nighttime sleep. NT1 is also characterized by cataplexy, brief episodes of muscle weakness usually triggered by strong emotions.

Previous studies have suggested that narcolepsy may differ between males and females in symptoms, sleep patterns, and time to diagnosis, but findings have been inconsistent. Many studies have also grouped together people with NT1 and narcolepsy type 2.

Age and the timing of disease onset may also influence these differences. Narcolepsy can present differently in children and adults, and some people diagnosed in adulthood may have first developed symptoms during childhood.

Study compares sex differences across age and disease onset

Researchers in China therefore set out to examine sex differences, as well as sex-specific symptom evolution over time, in 1,415 children and adults with NT1 recruited through Peking University People’s Hospital and other centers in the China Narcolepsy Surveillance Network. Most had not been receiving narcolepsy treatment before their evaluation.

For analyses based on age at symptom onset and diagnosis, 113 adults were excluded because their age at disease onset was unavailable, leaving 1,302 participants in three groups: 765 children whose symptoms began and who were diagnosed before age 18; 207 adults whose symptoms began and who were diagnosed at age 18 or older; and 330 adults whose symptoms began during childhood but who were diagnosed in adulthood.

Among the 765 children — 295 girls and 470 boys — there were no significant sex differences in when NT1 symptoms began, time to diagnosis, daytime sleepiness, or the presence or frequency of cataplexy.

Boys, however, were significantly more likely than girls (65.9% vs. 56.6%) to have an apnea-hypopnea index (AHI) of at least one event per hour, a threshold used to identify sleep apnea in children. Girls, meanwhile, had a significantly higher spontaneous arousal index, a measure of brief disruptions of sleep, at 9.31 vs. 8.2 events per hour.

Sex differences were more pronounced among the 207 adults whose NT1 began in adulthood — 54 women and 153 men. Women waited an average of 11.2 years from symptom onset to diagnosis, compared with 6.5 years for men, despite having a similar age at symptom onset.

Men with adult-onset NT1 show more sleep apnea

Men also had more sleep apnea. Nearly half (46.1%) had an AHI of at least 15 events per hour, indicating at least moderate sleep apnea, compared with 22.2% of women. Men also spent more time in lighter stage N1 sleep and less in deep stage N3 sleep, suggesting poorer sleep quality. The researchers suggested that the greater burden of sleep apnea in men may have contributed to these differences in sleep patterns.

The same pattern did not extend to the 330 adults — 121 women and 209 men — whose NT1 had started during childhood. In this group, diagnostic delay and key narcolepsy symptoms did not significantly differ between women and men, and there were no differences in N1 or N3 sleep.

Sleep apnea remained more common in men, however. About 21% of men versus 4% of women had an AHI of at least 15 events per hour.

Among 60 untreated participants — 18 females and 42 males — with follow-up data available, daytime sleepiness scores and cataplexy frequency decreased significantly from diagnosis to follow-up in males, but not females. However, the proportion of participants with clinically significant daytime sleepiness did not significantly change in either sex. The authors cautioned that the small number of participants makes these findings preliminary.

“Sex-related clinical and sleep characteristics changes across different-aged groups,” the researchers concluded. “Males appear to show improvement in symptoms over time than females.”