Depression: it’s a word we use a lot, but what exactly is it?



People with depression experience symptoms that affect their mood, cognitive function and physical health.
from http://www.shutterstock.com, CC BY-ND

Samuel Clack, Victoria University of Wellington and Tony Ward, Victoria University of Wellington

Depression is a serious disorder marked by disturbances in mood, cognition, physiology and social functioning.

People can experience deep sadness and feelings of hopelessness, sorrow, emptiness and despair. These core features of depression have expanded to include an inability to experience pleasure, sluggish movements, changes in sleep and eating behaviour, difficulty concentrating and suicidal thoughts.

The first diagnostic criteria were introduced in the 1980s. Now we have an expanded set of concepts for describing depression, from mild to severe, major depressive disorder, chronic depression and seasonal affective disorder.

Over the past 50 years, our understanding of depression has advanced significantly. But despite the wealth of research, there is no clear consensus on how this mental disorder should be explained. We propose a new route through the thicket.




Read more:
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Classifying mental disorders

How we describe and classify mental disorders is a fundamental step towards explaining and treating them. When carrying out research on people with depression, diagnostic categories such as major depressive disorder (MDD) shape our explanations. But if the descriptions are wrong, our explanations will suffer as a consequence.

The problem is that classification and explanation are not completely independent tasks. How we classify disorders directly impacts how we explain them, and these explanations in turn impact our classifications. In this way, psychiatry is stuck in a circular trap.

The danger – for depression and for other mental disorders – is that we tailor our explanations to fit the classifications available and that the classifications are inadequate.

Traditionally, research has focused on understanding mental disorders as classified in manuals such as the Diagnostic and Statistical Manual of Mental Disorders. Most of these disorders are what we call “psychiatric syndromes” – clusters of symptoms that hang together in some meaningful way and are assumed to share a common cause.

But many of these syndromes are poorly defined because disorders can manifest in different ways in different people. This is known as “disorder heterogeneity”. For example, there are 227 different symptom combinations that meet the criteria for major depressive disorder.




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Improving how we classify disorders

The other problem is that diagnostic criteria often overlap across multiple disorders. Symptoms of restlessness, fatigue, difficulty concentrating, irritability and sleep disturbance can be common for people experiencing generalised anxiety disorder or major depressive disorder.

This makes studying disorders like depression difficult. While we may think we are all explaining the same thing, we are actually trying to explain completely different variations of the disorder, or in some cases a completely different disorder.

A significant challenge is how to advance classification systems without abandoning their descriptive value and the decades of research they have produced. So what are our options?

A categorical approach, which sees disorders as discrete categories, has been the most prominent model of classification. But many researchers argue disorders such as depression are better seen as dimensional. For example, people who suffer from severe depression are just further along a spectrum of “depressed mood”, rather than being qualitatively different from the normal population.




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Novel classification approaches such as the hierarchical taxonomy of psychopathology and research domain criteria have been put forward. While these better accommodate the dimensional nature of disorders and are less complex to use, they are conceptually limited.

The former relies on current diagnostic categories and all the problems that come with that. The latter relies on neuro-centrism, which means mental disorders are viewed as disorders of the brain and biological explanations are used in preference to social and cultural explanations.

A new approach called the symptom network model offers a departure from the emphasis on psychiatric syndromes. It sees mental disorders not as diseases but as the result of interactions between symptoms.

In depression, an adverse life event such as loss of a partner may activate a depressed mood. This in turn may cause neighbouring symptoms, such as insomnia and fatigue. But this model is only descriptive and offers no explanation of the processes that cause the symptoms themselves.

A simple way forward

We suggest that one way of advancing understanding of mental disorders is to move our focus from psychiatric syndromes to clinical phenomena.

Phenomena are stable and general features. Examples in clinical psychology include low self-esteem, aggression, low mood and ruminative thoughts. The difference between symptom and phenomena is that the latter are inferred from multiple information sources such as behavioural observation, self-report and psychological test scores.

For example, understanding the central processes that underpin the clinical phenomenon of the inability to experience pleasure (anhedonia) will provide greater insight for cases that are dominated by this symptom.

In this way we can begin to tailor our explanations for individual cases rather than using general explanations of the broad syndrome “major depressive disorder”.

The other advantage is that the central processes that make up these phenomena are also more likely to form reliable clusters or categories. Of course, achieving this understanding will require greater specification of clinical phenomena we want to explain. It is not enough to conclude that a research finding (such as low levels of dopamine) is associated with the syndrome depression, as the features of depression may vary significantly between individuals.

We need to be more specific about exactly what people with depression in our research are experiencing.

Building descriptions of clinical phenomena will help us to better understand links between signs, symptoms and causes of mental disorder. It will put us in a better position to identify and treat depression.The Conversation

Samuel Clack, PhD Candidate, Victoria University of Wellington and Tony Ward, Professor of Clinical Psychology, Victoria University of Wellington

This article is republished from The Conversation under a Creative Commons license. Read the original article.

No, eating chocolate won’t cure depression



If you’re depressed, the headlines might tempt you to reach out for a chocolate bar. But don’t believe the hype.
from www.shutterstock.com

Ben Desbrow, Griffith University

A recent study published in the journal Depression and Anxiety has attracted widespread media attention. Media reports said eating chocolate, in particular, dark chocolate, was linked to reduced symptoms of depression.

Unfortunately, we cannot use this type of evidence to promote eating chocolate as a safeguard against depression, a serious, common and sometimes debilitating mental health condition.

This is because this study looked at an association between diet and depression in the general population. It did not gauge causation. In other words, it was not designed to say whether eating dark chocolate caused a reduction in depressive symptoms.




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What did the researchers do?

The authors explored data from the United States National Health and Nutrition Examination Survey. This shows how common health, nutrition and other factors are among a representative sample of the population.

People in the study reported what they had eaten in the previous 24 hours in two ways. First, they recalled in person, to a trained dietary interviewer using a standard questionnaire. The second time they recalled what they had eaten over the phone, several days after the first recall.

The researchers then calculated how much chocolate participants had eaten using the average of these two recalls.

Dark chocolate needed to contain at least 45% cocoa solids for it to count as “dark”.




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The researchers excluded from their analysis people who ate an implausibly large amount of chocolate, people who were underweight and/or had diabetes.

The remaining data (from 13,626 people) was then divided in two ways. One was by categories of chocolate consumption (no chocolate, chocolate but no dark chocolate, and any dark chocolate). The other way was by the amount of chocolate (no chocolate, and then in groups, from the lowest to highest chocolate consumption).




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The researchers assessed people’s depressive symptoms by having participants complete a short questionnaire asking about the frequency of these symptoms over the past two weeks.

The researchers controlled for other factors that might influence any relationship between chocolate and depression, such as weight, gender, socioeconomic factors, smoking, sugar intake and exercise.

What did the researchers find?

Of the entire sample, 1,332 (11%) of people said they had eaten chocolate in their two 24 hour dietary recalls, with only 148 (1.1%) reporting eating dark chocolate.

A total of 1,009 (7.4%) people reported depressive symptoms. But after adjusting for other factors, the researchers found no association between any chocolate consumption and depressive symptoms.

Few people said they’d eaten any chocolate in the past 24 hours. Were they telling the truth?
from www.shutterstock.com

However, people who ate dark chocolate had a 70% lower chance of reporting clinically relevant depressive symptoms than those who did not report eating chocolate.

When investigating the amount of chocolate consumed, people who ate the most chocolate were more likely to have fewer depressive symptoms.

What are the study’s limitations?

While the size of the dataset is impressive, there are major limitations to the investigation and its conclusions.

First, assessing chocolate intake is challenging. People may eat different amounts (and types) depending on the day. And asking what people ate over the past 24 hours (twice) is not the most accurate way of telling what people usually eat.

Then there’s whether people report what they actually eat. For instance, if you ate a whole block of chocolate yesterday, would you tell an interviewer? What about if you were also depressed?

This could be why so few people reported eating chocolate in this study, compared with what retail figures tell us people eat.




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Finally, the authors’ results are mathematically accurate, but misleading.

Only 1.1% of people in the analysis ate dark chocolate. And when they did, the amount was very small (about 12g a day). And only two people reported clinical symptoms of depression and ate any dark chocolate.

The authors conclude the small numbers and low consumption “attests to the strength of this finding”. I would suggest the opposite.

Finally, people who ate the most chocolate (104-454g a day) had an almost 60% lower chance of having depressive symptoms. But those who ate 100g a day had about a 30% chance. Who’d have thought four or so more grams of chocolate could be so important?

This study and the media coverage that followed are perfect examples of the pitfalls of translating population-based nutrition research to public recommendations for health.

My general advice is, if you enjoy chocolate, go for darker varieties, with fruit or nuts added, and eat it mindfully. — Ben Desbrow


Blind peer review

Chocolate manufacturers have been a good source of funding for much of the research into chocolate products.

While the authors of this new study declare no conflict of interest, any whisper of good news about chocolate attracts publicity. I agree with the author’s scepticism of the study.

Just 1.1% of people in the study ate dark chocolate (at least 45% cocoa solids) at an average 11.7g a day. There was a wide variation in reported clinically relevant depressive symptoms in this group. So, it is not valid to draw any real conclusion from the data collected.

For total chocolate consumption, the authors accurately report no statistically significant association with clinically relevant depressive symptoms.

However, they then claim eating more chocolate is of benefit, based on fewer symptoms among those who ate the most.

In fact, depressive symptoms were most common in the third-highest quartile (who ate 100g chocolate a day), followed by the first (4-35g a day), then the second (37-95g a day) and finally the lowest level (104-454g a day). Risks in sub-sets of data such as quartiles are only valid if they lie on the same slope.

The basic problems come from measurements and the many confounding factors. This study can’t validly be used to justify eating more chocolate of any kind. — Rosemary Stanton


Research Checks interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.The Conversation

Ben Desbrow, Associate Professor, Nutrition and Dietetics, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

More Australians are diagnosed with depression and anxiety but it doesn’t mean mental illness is rising



Women are almost twice as likely to be diagnosed with depression or anxiety as men.
Eric Ward

Anthony Jorm, University of Melbourne

Diagnoses of depression and anxiety disorders have risen dramatically over the past eight years. That’s according to new data out today from the Housing Income and Labour Dynamics (HILDA) Survey, which tracks the lives of 17,500 Australians.

The increase spans across all age groups, but is most notably in young people.

The percentage of young women (aged 15-34) who had been diagnosed with these conditions increased from 12.8% in 2009, to 20.1% in 2017.

In young men, there was a similar increase, from 6.1% to 11.2%.

But this doesn’t mean Australians’ mental health is worsening.




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What’s behind the numbers?

HILDA surveys collate data on the “reported diagnosis” of depression and anxiety disorders. Many people with these conditions have remained undiagnosed by a health practitioner, so it could simply be a matter of more people seeking professional help and getting diagnosed.

To find out whether there is a real increase, we need to survey a sample of the public about their symptoms rather than ask about whether they have been diagnosed. This has been done for almost two decades in the National Health Survey.

This graph shows the percentage of the population reporting very high levels of depression and anxiety symptoms over the previous month, from 2001 to 2017-18.

Rather than worsening, the nation’s mental health has been steady over this period.

Shouldn’t our mental health be improving?

So it seems while our mental health is not getting worse, we are more likely to get diagnosed. With increased diagnosis, it’s no surprise Australians have been rapidly embracing treatments for mental-health problems.

Antidepressant use has been rising for decades, with Australians now among the world’s highest users. One in ten Australian adults take an antidepressant each day.




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Psychological treatment has also skyrocketed, particularly after the Australian government introduced Medicare coverage for psychology services in 2006. There are now around 20 psychology services per year for every 100 Australians.

The real concern is why we’re not seeing any benefit from these large increases in diagnosis and treatment. In theory, our mental health should be improving.

There are two likely reasons for the lack of progress: the treatments are often not up to standard and we have neglected prevention.

Treatment is often poor quality

A number of treatments work for depression and anxiety disorders. However, what Australians receive in practice falls far short of the ideal.

Antidepressants, for example, are most appropriate for severe depression, but are often used to treat people with mild symptoms that reflect difficult life circumstances.

It takes more than a couple of sessions with a psychologist to treat a mental health disorder.
Kylli Kittus

Psychological treatments can be effective, but require many sessions. Around 16 to 20 sessions are recommended to treat depression. Getting a couple of sessions with a psychologist is too often the norm and unlikely to produce much improvement.

Treatments are also not distributed to the people most in need. The biggest users of antidepressants are older people, whereas younger people are more likely to experience severe depression.

Similarly, people in wealthier areas are more likely to get psychological therapy, but depression and anxiety disorders are more common in poorer areas.




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Prevention is neglected

The big area of neglect in mental health is prevention. Australia achieved enormous gains in physical health during the 20th century, with big drops in premature death. Prevention of disease and injury played a major role in these gains.

We might expect a similar approach to work for mental-health problems, which are the next frontier for improving the nation’s health. However, while we have been putting increasing resources into treatment, prevention has been neglected.

There is now good evidence that prevention of mental-health problems is possible and that it makes good economic sense. For every dollar invested on school-based interventions to reduce bullying, for instance, there is an estimated economic return of $14.

Much could to be done to reduce the major risk factors for mental-health problems which occur during childhood and increase risk right across the lifespan.

Parents who are in conflict with each other and fight a lot, for example, may increase their children’s risk for depression and anxiety disorders, while parents who show warmth and affection towards their children decrease their risk. Parents can be trained to reduce these risk factors and increase protective factors.

Yet successive Australian governments have lacked the political will to invest in prevention.

Where to next?

There is an important opportunity to consider whether Australia should be heading in a very different direction in its approach to mental health. The Australian government has asked the Productivity Commission to investigate mental health.

While we’ve had many previous inquiries, this one is different because it’s looking at the social and economic benefits of mental health to the nation. This broader perspective is important because action on prevention is a whole-of-government concern with resource implications and benefits that extend well beyond the health sector.




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The Conversation


Anthony Jorm, Professor emeritus, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Haphazard Posting


The last several months (and indeed the majority of the year – if not longer) has been marked by the haphazard and irregular nature of my posting to my Blogs and the updating of my websites. This is likely to continue for some time and for an indefinite period of time. Why? I have been battling depression (essentially), though I have no real understanding of why/how it has come about. A number of years ago I was involved in a car accident that nearly killed me and I suffered a brain injury as a result of the accident. I am as fully recovered as I am likely to be and it has not really left a great permanent impact on my life – though this depression may prove to have been its lasting legacy.

I have thought of closing down the Bogs and websites on a number of occasions – but have not really wanted to do so. I would like to return to them with the same enthusiasm that I once had, though I am obviously unsure when that will be. Also, closing down the sites would be like yielding to the mental illness and sliding further down the slippery slope, which is not something I want to do. So it’s six of one and half-dozen of the other as regards what to do.

So if you have been a regular reader/user of my sites I ask for your continuing patience and understanding – normal service is something I am aiming at returning to. I just don’t know when that can/will be.