Medical Bulletin 11/June/2025 - Video

Here are the top medical bulletins for the day:

Mood Disorders After 40 Could Signal Early Dementia: Study Finds

Mood disorders such as depression, mania, or bipolar disorder occurring after the age of 40 may be more than psychiatric issues—they could be early indicators of neurodegenerative diseases, according to a new study published in the journal Alzheimer’s and Dementia. Researchers from the National Institutes for Quantum Science and Technology (QST), Japan, suggest that late-life mood disorders (LLMDs) could precede the cognitive decline typically associated with conditions like Alzheimer’s disease.

To explore this potential link, the researchers studied 52 individuals diagnosed with late-life mood disorders and compared them with 47 healthy controls. Using advanced brain imaging, including positron emission tomography (PET) scans with two types of tracers, they assessed the presence of tau protein and amyloid beta—both biomarkers of neurodegenerative diseases.

The results were striking. Approximately 50% of individuals with late-life mood disorders showed abnormal tau protein accumulation in their brains, compared to only 15% of healthy controls. Similarly, amyloid deposits were detected in nearly 29% of the late-life mood disorders group but only 2% of the control group. The study also analyzed 208 autopsy cases, confirming a significantly higher prevalence of tau-related pathologies among individuals who had experienced late-life mood symptoms.

“Because most of the participants with late-life mood disorders in our study had no or mild cognitive decline, these results support the evidence that neurodegenerative diseases, including Alzheimer’s and non-Alzheimer’s tau-related pathologies, can initially manifest as psychiatric symptoms,” said Dr. Shin Kurose from QST. The study also found that tau accumulation often occurred in the brain's frontal regions—areas key to mood regulation and executive function.

Perhaps most notably, autopsy data revealed that mood symptoms preceded noticeable cognitive or motor symptoms by an average of 7.3 years. This suggests that mood disorders after midlife may offer a critical window for early diagnosis.

The researchers emphasized that recognizing late-life depression or mania as potential early signs of neurodegenerative disease could pave the way for earlier intervention with disease-modifying treatments—potentially changing the trajectory of conditions like Alzheimer’s.

Reference: Kurose S, Moriguchi S, Kubota M, et al. Diverse tau pathologies in late-life mood disorders revealed by PET and autopsy assays. Alzheimer's Dement. 2025; 21:e70195. https://doi.org/10.1002/alz.70195

Study Reveals How Stress Affects Memory and Sleep

A new study published in JNeurosci has uncovered a specific neural pathway that may explain how stress leads to poor sleep and memory issues—at least in males. The research sheds light on the brain mechanisms connecting emotional stress to sleep disruption and cognitive deficits.

It is well known that stress can take a toll on both sleep and memory. To investigate how this happens in the brain, researchers focused on the paraventricular nucleus (PVN) of the hypothalamus, a brain region already associated with stress responses. In their experiment, they artificially activated PVN neurons in male mice using advanced neurostimulation techniques.

The results were significant: mice with activated PVN neurons not only slept less but also performed worse in memory tasks compared to controls. This suggested a direct link between stress-sensitive brain activity and cognitive and sleep disturbances.

To further examine this connection, the researchers explored whether inhibiting these stress-associated PVN neurons might have the opposite effect. Indeed, when they suppressed the activity of these neurons in stressed mice, memory performance improved and sleep disruptions were slightly alleviated.

Digging deeper into the brain's circuitry, the team discovered that both stress and artificial stimulation of PVN neurons appeared to influence another brain region—the lateral hypothalamus (LH). This finding pointed to a previously unrecognized neural pathway from the PVN to the lateral hypothalamus that could be key in regulating how stress affects memory and sleep.

“These findings suggest that the PVN– lateral hypothalamus neural pathway may be involved in stress-related memory impairment and sleep disruptions,” the authors wrote. They added that this pathway may serve as a target for future research aimed at treating sleep and cognitive deficits in stress-related disorders.

Reference: Role of hypothalamic CRH neurons in regulating the impact of stress on memory and sleep

Alyssa Wiest, John J. Maurer, Kevin T. Beier, Franz Weber, Shinjae Chung

Journal of Neuroscience 9 June 2025, e2146242025; DOI: 10.1523/JNEUROSCI.2146-24.2025

Teen Sleep Habits May Predict Heart Health in Adulthood

Teens who maintain consistent, efficient sleep habits may be protecting their future heart health, according to new research published in the journal Sleep and to be presented at the SLEEP 2025 annual meeting. The study found that adolescents with earlier bedtimes, better sleep efficiency, and more consistent sleep schedules at age 15 had significantly better cardiovascular health by age 22.

Led by Gina Marie Mathew, a senior post-doctoral associate in public health at Stony Brook Renaissance School of Medicine, the study highlights the long-term health implications of sleep patterns during adolescence.

The research team analyzed longitudinal data from the Future of Families and Child Wellbeing Study, focusing on a diverse sample of 307 adolescents, 57% of whom were female. At age 15, participants wore wrist actigraphy devices for a week to objectively track their sleep behaviors. Sleep variables measured included bedtime, wake time, total sleep time, efficiency, and variability across nights.

At age 22, participants underwent cardiovascular assessments based on the American Heart Association’s Life’s Essential 8—excluding sleep—which includes diet, physical activity, nicotine exposure, body mass index, blood pressure, blood glucose, and blood lipids.

The findings revealed that earlier sleep timing, higher sleep maintenance efficiency, and lower night-to-night variability were all predictive of a higher cardiovascular health score at age 22. Interestingly, total sleep time during adolescence was not associated with future cardiovascular outcomes.

Mathew noted that the results highlight the need for a more comprehensive approach to address the relationship between adolescent sleep health and cardiovascular health. “Future research and recommendations should emphasize the importance of multiple dimensions of sleep health, including earlier sleep timing, higher sleep maintenance efficiency, and lower sleep variability as protective factors for long-term heart health,” Mathew said.

Reference: Gina Mathew, David Reichenberger, Orfeu Buxton, Anne-Marie Chang, Norrina Allen, Noreen Goldman, Donald Lloyd-Jones, Daniel Notterman, Lauren Hale, 0292 Poorer Actigraphic Sleep Health in Adolescence Predicts Lower Cardiovascular Health Score in Young Adulthood, Sleep, Volume 48, Issue Supplement_1, May 2025, Page A128, https://doi.org/10.1093/sleep/zsaf090.0292