Category: Mental Health

Mediterranean-type Diets Protect Against Parkinson’s Disease

Researchers at the University of British Columbia have shown that the Mediterranean diet and another diet based on it, have a strong link in protecting against Parkinson’s disease (PD). 

These two diets had previously been shown that they could protect against other neurodegenerative diseases. The Mediterranean‐DASH Intervention for Neurodegenerative Delay (MIND) diet combines aspects of the Mediterranean diet and the DASH diet which protects against hypertension. The MIND diet emphasises consumption of berries, as research shows that they protect against mental decline, eating leafy greens and poultry. The MIND diet also mostly does away with potato, milk and fruit (excluding berries).

Senior author Dr Silke Appel-Cresswell said, “There is a lack of medications to prevent or delay Parkinson’s disease yet we are optimistic that this new evidence suggests nutrition could potentially delay onset of the disease.”
Following the diets delayed the average onset of PD by 17.4 years in women, and 8.4 years in men.

Since PD already has a notable sex difference, with 60% of sufferers being men, despite their shorter average lifespan, the sex difference in response to the diets opens new avenues of research
“It drives home the connection between the gut and the brain for this disease,” Dr Brett Finlay said. “It also shows it’s not just one disease that healthy eating can affect, but several of these cognitive diseases.”

Source: Medical Xpress

Journal information: Avril Metcalfe‐Roach et al, MIND and Mediterranean Diets Associated with Later Onset of Parkinson’s Disease, Movement Disorders (2021). DOI: 10.1002/mds.28464

Depression May be Influenced by Metabolism

A study by researchers from University of California San Diego School of Medicine and from the Netherlands, has shown that major depressive disorder (MDD) may be predicted by metabolism, in the form of certain metabolites.

MDD is one of the most common disorders, with a lifetime prevalence of 20.6% in the United States. For those with recurrent major depressive disorder (rMDD), the risk is 80% over five years.

MDD is characterised by any combination of feelings of sadness or hopelessness, anger or frustration, loss of interest, sleep disturbances, anxiety, slowed or difficulty thinking, suicidal thoughts and unexplained pain such as backaches.

“This is evidence for a mitochondrial nexus at the heart of depression,” said senior author Prof Robert K Naviaux, at UC San Diego School of Medicine. “It’s a small study, but it is the first to show the potential of using metabolic markers as predictive clinical indicators of patients at greatest risk—and lower risk—for recurring bouts of major depressive symptoms.”

Recruiting 68 participants who were in remission for rMDD and not on antidepressants, the researchers found a range of molecules in participants’ blood that were up to 90% predictive of relapse in 30 months. The most predictive molecules consisted of certain lipids and purines.

Purines are produced from molecules such as ATP and ADP (major cellular energy storage molecules), and also have a role in signalling in stressed cells.The researchers found that in subjects with rMDD, certain metabolites in six metabolic pathways resulted in the alteration of key cellular activities.

“The findings revealed an underlying biochemical signature in remitted rMDD that set diagnosed patients apart from healthy controls,” Naviaux said. “These differences are not visible through ordinary clinical assessment, but suggest that the use of metabolomics—the biological study of metabolites—could be a new tool for predicting which patients are most vulnerable to a recurrence of depressive symptoms.”

Source: Medical Xpress

Journal information: Roel J. T. Mocking et al. Metabolic features of recurrent major depressive disorder in remission, and the risk of future recurrence, Translational Psychiatry (2021). DOI: 10.1038/s41398-020-01182-w

Autism Theory Treats its Characteristic Traits as Favoured by Society

For decades, scientists have fruitlessly sought a unifying aetiology for autism and an explanation for its prevalence, but now a new theoretical model describes the condition as a combination of traits that are common in autism and which are socially valued, combined with co-occurring disabilities.

An estimated 1 in 54 people have autism, which has been on the increase in developed countries. TA Meridian McDonald, PhD, a research instructor in Neurology at Vanderbilt University Medical Center, said: “Up until now there have been a lot of theories about the possible causes of autism but none of those theories account for the majority of autism cases. There are also a lot of theories as to why the prevalence of autism has been increasing in the population but, to date, there hasn’t been a theory that provides an explanatory model that accounts for all of those phenomena, including the genetics, social history, or characteristics of autism.”

She has worked on autism for 25 years, culminating in a theory called, “The Broader Autism Phenotype Constellation-Disability Matrix Paradigm (BAPCO-DMAP) Theory”, a focuses on the genetic basis of autism in line with current science but shifts the emphasis to positive traits selected for by events occurring over the past century.”The BAPCO-DMAP theory describes how people are attracted to other people who are very similar. They are attracted to certain traits that are very common in the population, and this leads to offspring who are more likely to have certain traits, as well as a greater intensity of traits,” said McDonald.

“The [BAPCO] traits are not what people expect. They expect the traits to be about challenges or difficulties, but instead there are six main traits—increased attention, increased memory, a preference for the object world vs. the social world and their environment, increased nonconformity, increased differences in sensory and perception, as well as systemising.”

These BAPCO traits are thus not necessarily negative, and can be combined with social skills. Counterintuitively, babies with increased memory and attention spans learn language later, because babies normally rely on their tiny attention span to break words down into their simplest sounds. With greater memory and attention spans, infants engage in echolalia, speaking long phrases without understanding them.

“You can often see children with autism engaging in sense-making activities, such as watching the same show over and over and memorising information,” McDonald said.The BAPCO traits are not by themselves significant impediments, but when combined with a disability such as an information processing disorder, then the combination leads to greater difficulties.

According to McDonald, the increased prevalence of autism in developed countries is due to men and women with BAPCO traits being able to pursue similar careers and passions, as opposed to being limited by circumstance, and results in relationships. This effectively concentrates BAPCO traits in any children they have.Since the BAPCO traits are socially valued, there simply is no “cure” for them, according to McDonald.”When we talk about autism we need to address the developmental disabilities that these individuals are experiencing but also find way to support and enhance their broader autism trait constellations,” she concluded.

Source: Medical Xpress

Journal information: T.A. Meridian McDonald, The broader autism phenotype constellations–disability matrix paradigm: Theoretical model for autism and the broader autism phenotype, Medical Hypotheses (2020). DOI: 10.1016/j.mehy.2020.110456

‘Flight or Flight’ Brain Region Linked to Heart Disease

Research on marmosets as reported in The Conversation has revealed the role that a region of the brain called sgACC plays in emotional arousal. Over-activity of sgACC was already associated with the dampening of pleasure and reward stimulus, seen in depression. 

A threat was presented to the marmosets in the form of a rubber snake and the marmosets were conditioned with a tone to create an association. The tone was later made without the snake to de-associate it from threat. The experimental group had over-activity induced in sgACC, the control group did not.

They found that marmosets who had not had sgACC over-stimulated responding normally to the de-association, calming down more quickly, but the over-activity group displayed fear and elevated blood pressure for much longer.

The over-activity of sgACC was also linked to abnormal heart function – increased heart rate and reduced variability in heart rate even at rest, without the presence of a threat.

Such changes reflect the presence of anxiety. The abnormal heart rates suggests that sgACC promotes the “flight or fight” response.
Brain imaging showed, with over-activity in sgACC, concurrent increased activity in the amygdala and hypothalamus, and reduced activity in the lateral prefrontal cortex, which is also seen in depression. Ketamine, a drug being investigated to treat depression, was shown to treat the depression aspects of sgACC over-activity, but in this case not anxiety – the marmosets remained fearful to stimulus.