Tag: neuropsychiatry

ADHD Tied to Raised Risk of Early Parkinson’s Disease

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By Alan Mozes

People with attention-deficit/hyperactivity disorder (ADHD) may be more than twice as likely to develop an early onset form of Parkinson’s, new research warns.

What’s more, among “those ADHD patients who had a record of being treated with amphetamine-like drugs — especially Ritalin [methylphenidate] — the risk dramatically increased, to between eight- to nine-fold,” said senior study author Glen Hanson.

But his team did not prove that ADHD or its medications actually caused Parkinson’s risk to rise, and one ADHD expert noted that the absolute risk of developing Parkinson’s remains very small.

For the study, researchers analyzed nearly 200,000 Utah residents. All had been born between 1950 and 1992, with Parkinson’s onset tracked up until the age of 60.

Prior to any Parkinson’s diagnosis, roughly 32,000 had been diagnosed with ADHD.

Hanson, a professor of pharmacology and toxicology at the University of Utah, said that ADHD patients were found to be “2.4 times more likely to develop Parkinson’s disease-like disorders prior to the age of 50 to 60 years,” compared with those with no history of ADHD. That finding held up even after accounting for a number of influential factors, including smoking, drug and alcohol abuse, and other psychiatric disorders.

“Although we cannot accurately say how much time elapsed between ADHD and [a] Parkinson’s-like disorder diagnosis, it was probably between 20 to 50 years,” he said.

As to what might explain the link, Hanson said that both ADHD and most forms of Parkinson’s source back to a “functional disorder of central nervous system dopamine pathways.”

In addition, Hanson said that “the drugs used to treat ADHD apparently work because of their profound effects on the activity of these dopamine pathways.” Theoretically, the treatment itself might trigger a metabolic disturbance, promoting dopamine pathway degeneration and, ultimately, Parkinson’s, he explained.

Still, Hanson pointed out that, for now, “we are not able to determine if the increased risk associated with stimulant use is due to the presence of the drug or the severity of the ADHD,” given that those treated with ADHD drugs tend to have more severe forms of the disorder.

And while demonstrating “a very strong association” between ADHD and Parkinson’s risk, the findings are preliminary, the study authors added.

Also, the absolute risk of developing Parkinson’s remained low, even in the most pessimistic scenario.

For example, the findings suggest that the risk of developing early onset Parkinson’s before the age of 50 would be eight or nine people out of every 100,000 with ADHD. This compares with one or two out of every 100,000 among those with no history of ADHD, the researchers said.

But the scientists noted that the results should raise eyebrows, because Parkinson’s primarily strikes people over the age of 60. Given the age range of those tracked so far in the study, Hanson said that his team was not yet able to ascertain Parkinson’s risk among ADHD patients after the age of 60.

Hanson also pointed out that because ADHD was only first diagnosed in the 1960s, only about 1.5 percent of the people in the study had an ADHD diagnosis, despite current estimates that peg ADHD prevalence at 10 percent. That suggests that the current findings may underestimate the scope of the problem.

“Clearly, there are some critical questions left to be answered concerning what is the full impact of this increased risk,” Hanson said.

Dr. Andrew Adesman is chief of developmental and behavioral pediatrics at Cohen Children’s Medical Center of New York with Northwell Health in New York City. He was not involved with the study and said the findings “surprised” him.

But, “we need to keep in mind that this study needs to be replicated and that the incidence of these conditions was very low, even among those with ADHD,” Adesman said. “The reality is that this would not affect 99.99 percent of individuals with ADHD.”

Meanwhile, Adesman said, “given that this study needs to be replicated, given that it is unclear whether ADHD medications further increase the risks of Parkinson’s, and given the very low risk in an absolute sense, I believe individuals with ADHD should not be hesitant to pursue or continue medical treatment for their ADHD.”

The report was published online Sept. 12 in the journal Neuropsychopharmacology.

Glen Hanson, DDS, Ph.D., vice dean and professor, pharmacology, School of Dentistry, University of Utah, Salt Lake City; Andrew Adesman, M.D., chief, developmental and behavioral pediatrics, Steven & Alexandra Cohen Children’s Medical Center of New York, Northwell Health, New York City; Sept. 12, 2018, Neuropsychopharmacology, online

https://consumer.healthday.com/cognitive-health-information-26/parkinson-s-news-526/adhd-tied-to-raised-risk-of-early-parkinson-s-737637.html

Scientists have found a previously unknown mechanism in which the protein tau, which is implicated in Alzheimer’s disease, damages brain cells by interfering with their internal communications.

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The discovery sheds new light on the origins of this most common cause of dementia, a hallmark of which is the buildup of tangled tau protein filaments in the brain.

The finding could also lead to new treatments for Alzheimer’s and other diseases that progressively destroy brain tissue, conclude the researchers in a paper about their work that now features in the journal Neuron.

Scientists from Massachusetts General Hospital (MGH) in Charlestown and the Johns Hopkins School of Medicine in Baltimore, MD, led the study, which set out to investigate how tau protein might contribute to brain cell damage.

Alzheimer’s disease does not go away and gets worse over time. It is the sixth most common cause of death in adults in the United States, where an estimated 5.7 million people have the disease.

Exact causes of Alzheimer’s still unknown

Exactly what causes Alzheimer’s and other forms of dementia is still a mystery to science. Evidence suggests that a combination of environment, genes, and lifestyle is involved, with different factors having different amounts of influence in different people.

Most cases of Alzheimer’s do not show symptoms until people are in their 60s and older. The risk of getting the disease rises rapidly with age after this.

Brain studies of people with the disease — together with postmortem analyses of brain tissue — have revealed much about how Alzheimer’s changes and harms the brain.

“Age-related changes” include: inflammation; shrinkage in some brain regions; creation of unstable, short-lived molecules known as free radicals; and disruption of cellular energy production.

The brain of a person with Alzheimer’s disease also has two distinguishing features: plaques of amyloid protein that form between cells, and tangles of tau protein that form inside cells. The recent study concerns the latter.

Changes to tau behavior

Brain cells, or neurons, have internal structures known as microtubules that support the cell and its function. They are highly active cell components that help carry substances from the body of the cell out to the parts that connect it to other cells.

In healthy brain cells, tau protein normally “binds to and stabilizes” the microtubules. Tau behaves differently, however, in Alzheimer’s disease.

Changes in brain chemistry make tau protein molecules come away from the microtubules and stick to each other instead.

Eventually, the detached tau molecules form long filaments, or neurofibrillary tangles, that disrupt the brain cell’s ability to communicate with other cells.

The new study introduces the possibility that, in Alzheimer’s disease, tau disrupts yet another mechanism that involves communication between the nucleus of the brain cell and its body.

Communication with cell nucleus

The cell nucleus communicates with the rest of the cell using structures called nuclear pores, which comprise more than 400 different proteins and control the movement of molecules.

Studies on the causes of amyotrophic lateral sclerosis, frontotemporal, and other types of dementia have suggested that flaws in these nuclear pores are involved somehow.

The recent study reveals that animal and human cells with Alzheimer’s disease have faulty nuclear pores, and that the fault is linked to tau accumulation in the brain cell.

“Under disease conditions,” explains co-senior study author Bradley T. Hyman, the director of the Alzheimer’s Unit at MGH, “it appears that tau interacts with the nuclear pore and changes its properties.”

He and his colleagues discovered that the presence of tau disrupts the orderly structure of nuclear pores containing the major structural protein Nup98. In Alzheimer’s disease cells, there were fewer of these pores and those that were there tended to be stuck to each other.

‘Mislocalized’ Nup98
They also observed another curious change involving Nup98 inside Alzheimer’s disease brain cells. In cells with aggregated tau, the Nup98 was “mislocalized” instead of staying in the nuclear pore.

They revealed that this feature was more exaggerated in brain tissue of people who had died with more extreme forms of Alzheimer’s disease.

Finally, when they added human tau to living cultures of rodent brain cells, the researchers found that it caused mislocalization of Nup98 in the cell body and disrupted the transport of molecules into the nucleus.

This was evidence of a “functional link” between the presence of tau protein and damage to the nuclear transport mechanism.

The authors note, however, that it is not clear whether the Nup98-tau interaction uncovered in the study just occurs because of disease or whether it is a normal mechanism that behaves in an extreme fashion under disease conditions.

They conclude:

“Taken together, our data provide an unconventional mechanism for tau-induced neurodegeneration.”

https://www.medicalnewstoday.com/articles/322991.php

Targeting astrocytes, the brain cells that support neurons, in the brain might help alleviate symptoms of Alzheiemer’s disease

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A study by scientists of the German Center for Neurodegenerative Diseases (DZNE) points to a novel potential approach against Alzheimer’s disease. In studies in mice, the researchers were able to show that blocking a particular receptor located on astrocytes normalized brain function and improved memory performance. Astrocytes are star-shaped, non-neuronal cells involved in the regulation of brain activity and blood flow. The findings are published in the Journal of Experimental Medicine (JEM).

Alzheimer’s disease is a common and currently incurable brain disorder leading to dementia, whose mechanisms remain incompletely understood. The disease appears to be sustained by a combination of factors that include pathological changes in blood flow, neuroinflammation and detrimental changes in brain cell activity.

“The brain contains different types of cells including neurons and astrocytes”, explains Dr. Nicole Reichenbach, a postdoc researcher at the DZNE and first author of the paper published in JEM. “Astrocytes support brain function and shape the communication between neurons, called synaptic transmission, by releasing a variety of messenger proteins. They also provide metabolic and structural support and contribute to the regulation of blood flow in the brain.”

Glitches in network activity

Similar to neurons, astrocytes are organized into functional networks that may involve thousands of cells. “For normal brain function, it is crucial that networks of brain cells coordinate their firing rates. It’s like in a symphony orchestra where the instruments have to be correctly tuned and the musicians have to stay in synchrony in order to play the right melody”, says Professor Gabor Petzold, a research group leader at the DZNE and supervisor of the current study. “Interestingly, one of the main jobs of astrocytes is very similar to this: to keep neurons healthy and to help maintain neuronal network function. However, in Alzheimer’s disease, there is aberrant activity of these networks. Many cells are hyperactive, including neurons and astrocytes. Hence, understanding the role of astrocytes, and targeting such network dysfunctions, holds a strong potential for treating Alzheimer’s.”

Astrocyte-targeted treatment alleviated memory impairment

Petzold and colleagues tested this approach in an experimental study involving mice. Due to a genetic disposition, these rodents exhibited certain symptoms of Alzheimer’s similar to those that manifest in humans with the disease. In the brain, this included pathological deposits of proteins known as “Amyloid-beta plaques” and aberrant network activity. In addition, the mice showed impaired learning ability and memory.

In their study, the DZNE scientists targeted a cell membrane receptor called P2Y1R, which is predominately expressed by astrocytes. Previous experiments by Petzold and colleagues had revealed that activation of this receptor triggers cellular hyperactivity in mouse models of Alzheimer’s. Therefore, the researchers treated groups of mice with different P2Y1R antagonists. These chemical compounds can bind to the receptor, thus switching it off. The treatment lasted for several weeks.

“We found that long-term treatment with these drugs normalized the brain’s network activity. Furthermore, the mice’s learning ability and memory greatly improved”, Petzold says. On the other hand, in a control group of wild type mice this treatment had no significant effect on astrocyte activity. “This indicates that P2Y1R inhibition acts quite specifically. It does not dampen network activity when pathological hyperactivity is absent.”

New approaches for research and therapies?

Petzold summarizes: “This is an experimental study that is currently not directly applicable to human patients. However, our results suggest that astrocytes, as important safeguards of neuronal health and normal network function, may hold the potential for novel treatment options in Alzheimer’s disease.” In future studies, the scientists intend to identify additional novel pathways in astrocytes and other cells as potential drug targets.

Reference:
Reichenbach, N., Delekate, A., Breithausen, B., Keppler, K., Poll, S., Schulte, T., . . . Petzold, G. C. (2018). P2Y1 receptor blockade normalizes network dysfunction and cognition in an Alzheimer’s disease model. The Journal of Experimental Medicine. doi:10.1084/jem.20171487

https://www.dzne.de/en/news/public-relations/press-releases/press/detail/the-brains-rising-stars-new-options-against-alzheimers/

Laboratory mouse studies suggest that long-term, low dose caffeine worsens anxiety and emotional and cognitive flexibility in people with Alzheimer’s disease, while providing only little benefit to learning and memory.

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The study simulated long-term consumption of three cups of coffee a day.

It is well known that memory problems are the hallmarks of Alzheimer’s disease. However, this dementia is also characterized by neuro-psychiatric symptoms, which may be strongly present already in the first stages of the disorder. Known as Behavioural and Psychological Symptoms of Dementia (BPSD), this array of symptoms — including anxiety, apathy, depression, hallucinations, paranoia and sundowning (or late-day confusion) — are manifested in different manners depending on the individual patient, and are considered the strongest source of distress for patients and caregivers.


Coffee and caffeine: good or bad for dementia?

Caffeine has recently been suggested as a strategy to prevent dementia, both in patients with Alzheimer’s disease and in normal ageing processes. This is due to its action in blocking molecules — adenosine receptors — which may cause dysfunctions and diseases in old age. However, there is some evidence that once cognitive and neuro-psychiatric symptoms develop, caffeine may exert opposite effects.

To investigate this further, researchers from Spain and Sweden conducted a study with normal ageing mice and familial Alzheimer’s models. The research, published in Frontiers in Pharmacology, was conducted from the onset of the disease up to more advanced stages, as well as in healthy age-matched mice.

“The mice develop Alzheimer’s disease in a very close manner to human patients with early-onset form of the disease,” explains first author Raquel Baeta-Corral, from Universitat Autònoma de Barcelona, Spain. “They not only exhibit the typical cognitive problems but also a number of BPSD-like symptoms. This makes them a valuable model to address whether the benefits of caffeine will be able to compensate its putative negative effects.”

“We had previously demonstrated the importance of the adenosine A1 receptor as the cause of some of caffeine’s adverse effects,” explains Dr. Björn Johansson, a researcher and physician at the Karolinska University Hospital, Sweden.

“In this study, we simulated a long oral treatment with a very low dose of caffeine (0.3 mg/mL) — equivalent to three cups of coffee a day for a human — to answer a question which is relevant for patients with Alzheimer’s, but also for the ageing population in general, and that in people would take years to be solved since we would need to wait until the patients were aged.”

Worsened Alzheimer’s symptoms outweigh cognition benefits

The results indicate that caffeine alters the behavior of healthy mice and worsens the neuropsychiatric symptoms of mice with Alzheimer’s disease. The researchers discovered significant effects in the majority of the study variables — and especially in relation to neophobia (a fear of everything new), anxiety-related behaviors, and emotional and cognitive flexibility.

In mice with Alzheimer’s disease, the increase in neophobia and anxiety-related behaviours exacerbates their BPSD-like profile. Learning and memory, strongly influenced by anxiety, got little benefit from caffeine.

“Our observations of adverse caffeine effects in an Alzheimer’s disease model, together with previous clinical observations, suggest that an exacerbation of BPSD-like symptoms may partly interfere with the beneficial cognitive effects of caffeine. These results are relevant when coffee-derived new potential treatments for dementia are to be devised and tested,” says Dr. Lydia Giménez-Llort, researcher from the INc-UAB Department of Psychiatry and Legal Medicine, Universitat Autònoma de Barcelona, and lead researcher of the project.

The results of the study form part of the PhD thesis of Raquel Baeta-Corral, first author of the article, and are the product of a research led by Lydia Giménez-Llort, Director of the Medical Psychology Unit, Department of Psychiatry and Legal Medicine and researcher at the UAB Institute of Neuroscience, together with Dr Björn Johansson, Researcher at the Department of Molecular Medicine and Surgery, Karolinska Institutet and the Department of Geriatrics, Karolinska University Hospital, Sweden, under the framework of the Health Research Fund project of the Institute of Health Carlos III.

Long-term caffeine worsens symptoms associated with Alzheimer’s disease

Computers are now able to predict who will develop psychosis years later based on analysis of their speech patterns.

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An automated speech analysis program correctly differentiated between at-risk young people who developed psychosis over a two-and-a-half year period and those who did not. In a proof-of-principle study, researchers at Columbia University Medical Center, New York State Psychiatric Institute, and the IBM T. J. Watson Research Center found that the computerized analysis provided a more accurate classification than clinical ratings. The study, “Automated Analysis of Free Speech Predicts Psychosis Onset in High-Risk Youths,” was recently published in NPJ-Schizophrenia.

About one percent of the population between the age of 14 and 27 is considered to be at clinical high risk (CHR) for psychosis. CHR individuals have symptoms such as unusual or tangential thinking, perceptual changes, and suspiciousness. About 20% will go on to experience a full-blown psychotic episode. Identifying who falls in that 20% category before psychosis occurs has been an elusive goal. Early identification could lead to intervention and support that could delay, mitigate or even prevent the onset of serious mental illness.
Speech provides a unique window into the mind, giving important clues about what people are thinking and feeling. Participants in the study took part in an open-ended, narrative interview in which they described their subjective experiences. These interviews were transcribed and then analyzed by computer for patterns of speech, including semantics (meaning) and syntax (structure).

The analysis established each patient’s semantic coherence (how well he or she stayed on topic), and syntactic structure, such as phrase length and use of determiner words that link the phrases. A clinical psychiatrist may intuitively recognize these signs of disorganized thoughts in a traditional interview, but a machine can augment what is heard by precisely measuring the variables. The participants were then followed for two and a half years.
The speech features that predicted psychosis onset included breaks in the flow of meaning from one sentence to the next, and speech that was characterized by shorter phrases with less elaboration. The speech classifier tool developed in this study to mechanically sort these specific, symptom-related features is striking for achieving 100% accuracy. The computer analysis correctly differentiated between the five individuals who later experienced a psychotic episode and the 29 who did not. These results suggest that this method may be able to identify thought disorder in its earliest, most subtle form, years before the onset of psychosis. Thought disorder is a key component of schizophrenia, but quantifying it has proved difficult.

For the field of schizophrenia research, and for psychiatry more broadly, this opens the possibility that new technology can aid in prognosis and diagnosis of severe mental disorders, and track treatment response. Automated speech analysis is inexpensive, portable, fast, and non-invasive. It has the potential to be a powerful tool that can complement clinical interviews and ratings.

Further research with a second, larger group of at-risk individuals is needed to see if this automated capacity to predict psychosis onset is both robust and reliable. Automated speech analysis used in conjunction with neuroimaging may also be useful in reaching a better understanding of early thought disorder, and the paths to develop treatments for it.

http://medicalxpress.com/news/2015-08-psychosis-automated-speech-analysis.html