Experiencing daytime sleepiness is something that is usually perceived as a minor inconvenience, but for older adults, it could be an early warning sign of Dementia. This neurodegenerative disease leads to the progressive decline of brain cells. This eventually

affects memory, cognition, and personality, making everyday tasks more difficult. As one of the fastest-growing neurological disorders across the world, dementia poses a significant health threat to ageing populations.

Is Dementia Linked To Poor Sleep?

For this study, researchers followed 445 older adults (average age 76) over three years, aiming to determine whether poor sleep could increase the risk of mild cognitive impairment (MCI), which often leads to dementia. At the start, none of the participants had MCI, but by the end of the study, 36 individuals had developed the condition.

The researchers discovered that participants with poor sleep were more likely to develop MCI compared to those who slept well. However, when depression symptoms were taken into account, the link between poor sleep and MCI became less pronounced, suggesting that while sleep issues are a concern, mental health also plays a key role in dementia risk.

To assess sleep quality, the Pittsburgh Sleep Quality Index (PSQI) was used, evaluating factors such as sleep duration, disturbances, and daytime alertness. Among these, "daytime dysfunction"—defined as excessive sleepiness and low energy during the day—was most strongly associated with an increased risk of MCI. Those experiencing daytime dysfunction were more than three times as likely to develop MCI as those who didn’t report such symptoms.

There are many types of dementia:

Dementia is not a specific disease. According to the Centers for Disease Control and Prevention (CDC), it is an overall term that describes a decline in mental ability that interferes with daily life. People with dementia often have symptoms like trouble remembering, thinking, or making everyday decisions. These symptoms tend to get worse over time.

Alzheimer’s disease is the most common type of dementia, and it mostly affects the elderly. Each form of dementia has a different cause. Though dementia mostly affects older adults, it is not a part of normal ageing. An estimated 6.7 million older adults have Alzheimer's disease in the United States. That number is expected to double by 2060, as per data from the CDC.

In 2022, 3.8% of men and 4.2% women in US were diagnosed with dementia. The percentage of people increase with age from 1.7% for those aged 65-74 to 13.1% for those aged 85 and older. Alzheimer's accounts for 60 to 80% of all dementia cases and it is most prevalent in California, Florida, and Texas, as these states have the highest number of people.

Scientists have identified a rare contagious skin cancer in brown bullhead catfish living in lakes across the US and Canada's Quebec, marking only the fourth known case of a naturally transmissible cancer in the animal kingdom.

A team led by the University of Vermont found that mysterious black skin lesions affecting brown bullhead catfish in Lake Memphremagog and other lakes in New England and Quebec were caused by a transmissible melanoma—the first such cancer ever identified in a freshwater fish species.

The findings, published in the journal Nature, add freshwater fish to a short list of species known to develop cancers that spread through the transfer of living cancer cells. Previously, transmissible cancers had been identified only in Tasmanian devils (facial tumor disease), dogs (canine transmissible venereal tumor), and shellfish, including clams, mussels, and other bivalve mollusks (leukemia-like transmissible cancers).

“The cancer cells behave more like parasites than conventional tumors, moving from fish to fish,” said the researchers led by the University of Vermont.

"The discovery sheds light on how cancer can spread in the wild and raises important questions about where this cancer originated, how it will affect fish health and populations—and how cancer works in all animals including humans," they added.

How Was Cancer Identified In Fish?

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Since 2012, anglers and biologists have reported increasing numbers of brown bullhead catfish with raised black skin patches in Lake Memphremagog, which straddles Vermont and Quebec. By 2014, nearly one in three fish examined had developed the dark lesions.

Initially, researchers believed the disease might be caused by a virus. They later suspected pollution or another environmental pathogen. However, further investigation revealed that the lesions were actually melanoma.

“This was surprising, and we wanted to know how a bottom-dwelling fish was getting a cancer we associate with exposure to too much sunlight,” said Julie Dragon, a scientist at the University of Vermont.

Using whole-genome sequencing, the team identified hundreds of thousands of shared genetic variants among tumor samples that were absent from the host fish, confirming that the cancer spreads between animals through living cancer cells.

How Does The Cancer Spread?

Researchers are now trying to determine exactly how the cancer moves from one fish to another. They believe that the tumors appear only "in larger fish that are of spawning age".

Mark Henderson, a fish biologist and study co-leader in UVM’s Rubenstein School of Environment and Natural Resources said that it “maybe some part of spawning behavior leads to the spreading of the cancer between animals."

During spawning, brown bullhead gather closely in shallow water, allowing physical contact that could transfer tumor cells. Because the fish lack scales and spend much of their time on lake bottoms, scientists also believe sediments could harbor free-floating cancer cells.

The study also suggests that naturally occurring arsenic or hormonal changes may weaken the fish's immune system, making them more susceptible to infection.

Should Humans Worry?

Despite the unusual discovery, researchers stress that there is no known risk to humans.

Lake Memphremagog supplies drinking water to more than 175,000 people, but scientists say the cancer cells cannot infect or survive in another species. They also state that the fish are safe to handle for research and monitoring.

Fish remains a highly nutritious food, rich in high-quality protein, vitamin D, and omega-3 fatty acids that support heart and brain health.

Quebec's Ministry of the Environment recommends not eating fish with tumors, even though there is no evidence that doing so poses a risk to human health.

The findings raise broader questions about how pollution, habitat stress, and climate change may influence the evolution and spread of diseases in wildlife.

With long COVID continuing to affect millions, a recent study has emerged, suggesting that women are more likely to bear its neurological burden than men.

According to a new study from Northwestern Medicine, female patients reported more severe neurological symptoms, poorer cognitive function, and a greater decline in quality of life.

Published in the Annals of Clinical and Translational Neurology, the study analyzed 2,329 adults evaluated at Northwestern Medicine's Neuro COVID-19 Clinic between May 2020 and August 2025. Researchers compared neurological symptoms in patients, examining differences between men and women.

Women Reported More Neurological Symptoms

Researchers found that women, on average, reported significantly more neurological symptoms about 16 months after their COVID-19 illness than men. Among the most commonly reported symptoms were:

• Brain fog
• Fatigue
• Numbness and tingling
• Dizziness
• Headaches
• Muscle pain
• Blurred vision
• Tinnitus (ringing in the ears)
• Altered smell and taste

Women also scored worse on measures of cognitive performance and reported a greater impact on their overall quality of life.

Lead author Dr. Igor Koralnik, chief of Neuroinfectious Diseases and Global Neurology at Northwestern Medicine, said, "While previous studies showed that women are more likely to develop long COVID, this is the first study demonstrating that women also experience more severe neurological symptoms, worse cognitive function and greater reductions in quality of life than men."

First author Dr. Aurore Gorenshtein added, "Recognizing these sex-specific differences is important because it may help clinicians provide more personalized care and improve treatment strategies for people living with neurological long COVID."

Why Might Women Be More Affected?

Even though the study did not narrow down the exact causes behind these differences, researchers believe that several biological and immune-related factors could contribute. Here are some possible explanations:

• Differences in immune system responses between men and women
• Hormonal influences, particularly estrogen
• More likelihood of autoimmune conditions among women
• Differences in inflammation and nervous system responses after SARS-CoV-2 infection

Earlier Studies

The new research aligns with earlier findings from the U.S. National Institutes of Health's RECOVER Initiative, which showed that females are generally more likely than males to develop long COVID. That analysis also suggested the risk is highest among women aged 40 to 54 years, particularly before menopause.

A study recently found out that long COVID may directly injure the brain's dopamine system, offering an explanation for symptoms like fatigue, brain fog, poor memory, slowed movement, and lack of motivation that persist long after the initial infection. The latest findings shed more light on deeper effects of long COVID on brain health.

Long COVID remains a major public health challenge, with neurological symptoms among the most persistent and disabling. Brain fog, memory problems, chronic fatigue, headaches and dizziness can significantly affect employment, education and daily life.

The latest findings suggest that healthcare providers may need to consider sex-specific approaches when evaluating and managing patients with neurological long COVID, ensuring women receive earlier recognition, cognitive assessments and personalised rehabilitation.

Montelukast, a widely prescribed medication for asthma and allergies, may cause significant psychiatric side effects that remain underdiagnosed and underreported, according to researchers.

The researchers, from the University of California, Davis in the US, and Curtin University in Australia, said many psychiatrists are still unaware of the US Food and Drug Administration's (FDA) black-box warning on the drug's mental health risks.

In 2020, the FDA had required a black-box warning for montelukast, citing the risk of serious behavior and mood-related changes, including suicidal thoughts or actions.

Neuropsychiatric Side Effects More Common

Writing in Psychiatry Online, the researchers said that estimates of montelukast-related neuropsychiatric events range from 5.9% to 62%.

Reported psychiatric side effects include:

• Aggression
• Anxiety
• Depression
• Suicidal thoughts and behavior

Symptoms may appear soon after starting the medication, after prolonged use, or even following its withdrawal.

Children at Greater Risk

The researchers noted that children appear to be disproportionately affected, partly because montelukast is available as a chewable tablet that is easier for young children to take than inhaled medications.

Citing a 2016 study, they wrote that completed suicides were reported more frequently among children than among adolescents or the overall population.

Behavioral changes in children may also be mistaken for normal developmental phases, delaying recognition of a possible drug-related cause.

The researchers also highlighted testimony presented at a 2022 US National Center for Toxicological Research (NCTR) meeting, where a parent described severe behavioral changes in her three-year-old son after taking montelukast.

Many parents at the meeting said they only discovered the possible link between the medication and psychiatric symptoms by chance, despite consulting multiple healthcare providers.

Why the Link Is Often Missed

Researchers said patients and clinicians frequently fail to connect psychiatric symptoms with montelukast because there is no obvious reason to suspect the medication.

They also argued that inadequate communication from drug manufacturers and health regulators has contributed to low awareness, despite safety warnings issued in several countries.

They cautioned that abruptly stopping montelukast may also worsen psychiatric symptoms, making clinical evaluation essential.

What Psychiatrists Can Do

The researchers recommend that psychiatrists consider montelukast as a possible cause when psychiatric symptoms develop after the medication is started.

If a link is suspected, psychiatrists should coordinate with the patient's primary care physician to discuss alternative treatments for asthma or allergies and monitor whether psychiatric symptoms improve.

They also advise clinicians to:

• Consider montelukast use during emergency assessments for suicidal thoughts or suicide attempts.
• Monitor hospitalized patients who begin montelukast for newly emerging depression, anxiety, and suicidal ideation.

What the FDA Says

The FDA states that montelukast prescribing information already includes warnings about mental health side effects, including suicidal thoughts or actions. However, it notes that many healthcare professionals and patients remain unaware of these risks.

The agency advises that:

• For allergic rhinitis (hay fever), montelukast should be reserved for patients who do not respond to or cannot tolerate other allergy medications.
• For asthma, healthcare professionals should carefully weigh the benefits against the potential risk of mental health side effects before prescribing the drug.