Category: Depression

New research reveals why so many people are affected by the ‘winter blues’.

Scientists have found that people who have Seasonally Affected Disorder (SAD) show important differences in the way the neurotransmitter serotonin is regulated in the brain.

Serotonin is thought to play a part in how our moods change.

The researchers at the University of Copenhagen scanned the brains of 34 people using positron emission tomography (PET) in both the summer and winter months (Mc Mahon et al., 2014).

Eleven had SAD and 23 were healthy participants.

The results — to be presented at a neuropsychopharmacology conference this week — showed significant differences in the levels of a protein that transports serotonin.

The levels of the protein were around 5% higher in SAD patients, which leads to lower levels of serotonin in the winter.

People without SAD showed similar levels of the serotonin transporter in both winter and summer.

The study’s lead author, Brenda Mc Mahon, explained:

“We believe that we have found the dial the brain turns when it has to adjust serotonin to the changing seasons.

The serotonin transporter (SERT) carries serotonin back into the nerve cells where it is not active, so the higher the SERT activity the lower the activity of serotonin.

Sunlight keeps this setting naturally low, but when the nights grow longer during the autumn, the SERT levels increase, resulting in diminishing active serotonin levels.

Many individuals are not really affected by SAD, and we have found that these people don’t have this increase in SERT activity, so their active serotonin levels remain high throughout the winter”.

Seasonally affected disorder is experienced by one in six people in more northerly climates, where the winter is worse.

In the United States, the prevalence in sunny Florida is only around 1.4%, while in less sunny New Hampshire it is 9.7%.

Typical symptoms include having little energy, sleeping too much, overeating, nausea and sometimes feeling depressed.

Image credit: martinak15

New study reveals how exercise helps the body remove toxic substances linked to depression.

On top of its physical benefits, exercise has a huge range of psychological benefits — but until now it was not known how or why exercise is so beneficial.

Now, a new study has uncovered how exercise protects the brain from stress-related depression.

Researchers at Sweden’s Karolinska Institutet have found that exercise causes important changes in skeletal muscles.

These changes help to purge the blood of substances harmful to the brain which build up during stress.

Their conclusions, published in the journal Cell, come from a study of mice which were bred with high levels of a particular protein which is elevated by exercise, called PGC-1a1 (Agudelo et al., 2014).

This super-race of well-muscled ‘gym mice’ were then exposed to stress, as were a batch of normal mice.

Both were given the mouse equivalent of five really bad weeks at the office: they had their sleep disrupted, lights flashed at them and loud noises piped into their cages.

After the five weeks were over, both groups of mice were tested for depressive behaviour.

While the normal mice showed signs of depression, the gym mice behaved absolutely normally, as though nothing had happened.

Dr. Jorge Ruas, who led the study, said:

“Our initial research hypothesis was that trained muscle would produce a substance with beneficial effects on the brain.

We actually found the opposite: well-trained muscle produces an enzyme that purges the body of harmful substances.

So in this context the muscle’s function is reminiscent of that of the kidney or the liver.”

The mice with higher levels of the protein PGC-1a1 also had higher levels of enzymes called KAT.

It is these enzymes that convert the substance formed during stress (kynurenine) into an acid, which cannot pass the blood-brain barrier.

Even injecting the gym mice with kynurenine couldn’t make them depressed, as their KAT enzymes produced by their muscles quickly converted it to a more harmless substance.

Dr. Ruas continued:

“It’s possible that this work opens up a new pharmacological principle in the treatment of depression, where attempts could be made to influence skeletal muscle function instead of targeting the brain directly.

Skeletal muscle appears to have a detoxification effect that, when activated, can protect the brain from insults and related mental illness.”

• Read on: 20 Wonderful Effects Exercise Has on the Mind

Image credit: The Q Speaks

A serious mental health problem can reduce life expectancy by 10 to 20 years, according to a new analysis by psychiatrists.

In comparison, the loss of years due to heavy smoking is around 8 – 10.

Researchers from Oxford University analysed studies which included 1.7 million people, reporting 250,000 deaths to compare the effects of smoking and serious mental health problems (Chesney et al., 2014).

One of the study’s authors, Dr Seena Fazel, explained:

“We found that many mental health diagnoses are associated with a drop in life expectancy as great as that associated with smoking 20 or more cigarettes a day.

There are likely to be many reasons for this.

High-risk behaviors are common in psychiatric patients, especially drug and alcohol abuse, and they are more likely to die by suicide.

The stigma surrounding mental health may mean people aren’t treated as well for physical health problems when they do see a doctor.”

Here are the average life expectancy losses for some of the major mental health problems:

• Recurrent depression: 7 – 11 years.
• Schizophrenia: 10 – 20 years.
• Bipolar disorder: 9 – 20 years.
• Drug and alcohol abuse: 9 – 24 years.

Figures from the UK show that about 21% of British men smoke and 19% of women.

In comparison, over the course of a year, 25% of people will experience a mental health problem, although most will not be as life threatening as those listed above.

Fazel continued:

“All of this can be changed. There are effective drug and psychological treatments for mental health problems.

We can improve mental health and social care provision.

That means making sure people have straightforward access to health care and appropriate jobs and meaningful daytime activities.

It’ll be challenging, but it can be done.”

Image credit: kygp

Connection found between a brain network implicated in depression and levels of serotonin in the bloodstream.

Scientists have claimed that it is possible to detect the signs of depression using a blood test, despite many believing it is impossible.

The claim comes from researchers at the Medical University of Vienna, who have found a close relationship between a brain network implicated in depression and levels of serotonin in the bloodstream (Scharinger et al., 2014).

The study’s lead author, Lukas Pezawas said:

“This is the first study that has been able to predict the activity of a major depression network in the brain using a blood test.

While blood tests for mental illnesses have until recently been regarded as impossible, this study clearly shows that a blood test is possible in principle for diagnosing depression and could become reality in the not too distant future.”

A wandering mind

The network Pezawas is referring to is sometimes called the ‘default mode network’: essentially it means the areas of the brain which kick into action when our minds are wandering.

One of the components of depression is excessive mind-wandering to negative thoughts and an inability to concentrate.

Interestingly, people with depression also tend to have problems suppressing activity in the brain’s default mode network.

The blood test that the team envisages would measure the level of serotonin in the blood.

Serotonin in the brain — sometimes known as the ‘happiness hormone’ — plays an important role in regulating the default mode network.

What the researchers have discovered is that serotonin function in the blood (not the brain) nevertheless predicts activity in the default mode network.

In other words: you can do a blood test on someone and it will tell you something about the function of a brain network which has been associated with depression.

Depression is about more than just serotonin

This study is fascinating and may eventually lead to a useful diagnostic tool, but it’s worth pointing out a few reservations:

• Depression is about way more than just serotonin levels. If it were, the current batch of SSRI anti-depressant drugs, which target serotonin, would work much better than they do (which is: not that well).
• Depression can’t be explained just by activity of the default mode network.
• Depression is not like a switch, either ‘on’ or ‘off’, it’s a sliding scale. Thinking of it like a biological disease which you either have or don’t have is not helpful. Mainly because it’s not true.
• If you want to find out if someone is depressed, just ask them. The answer may not be as clear and feel as scientific as a blood test, but it may be more useful.

Image credit: kygp

Despite the psychological benefits, 70% of US retirees are not online, study finds.

Retired people who use the internet are about one-third less likely to suffer from depression, compared to those who do not go online.

The new study also finds that the positive effects of the internet were particularly strong for those who live alone (Cotten et al., 2014).

The authors of the study explain:

“Number of people in the household partially mediates this relationship, with the reduction in depression largest for people living alone.

This provides some evidence that the mechanism linking Internet use to depression is the remediation of social isolation and loneliness.

Encouraging older adults to use the Internet may help decrease isolation, loneliness, and depression.” (Cotten et al., 2014)

The research included data from 3,075 retired Americans who were living in the community.

The data was collected at four time-points between 2002 and 2008.

The authors of the study explain that:

“Retired persons are a population of interest, particularly because one mechanism by which Internet use may affect depression is to counter the effects of isolation and loneliness, which are more common among older adults.

Also, working individuals may be required to use the Internet rather than choosing to, and may use the technology for different reasons than those not working.”

We know from previous studies that older people are mostly interested in using the internet to communicate with their friends and family.

This is especially useful for them as many have mobility issues.

Despite its beneficial effects, 70% of the retirees in this study were NOT online.

If you are thinking about getting your parents or grandparents online, this study should provide an extra incentive.

Image credit: Louisa Billeter

How much extra sleep can make a difference to adolescent depression?

A new study finds a link between later start times at school and improved mood and sleep in teenagers.

The study, published in the Journal of Developmental & Behavioral Pediatrics, delayed the waking up time of adolescents at a boarding school by just 25 minutes (Boergers et al., 2013).

They found that afterwards the number of students getting more than 8 hours sleep a night jumped from 18% to 44%.

On top of this, the students experienced less daytime sleepiness, were less depressed, and found themselves using less caffeine.

Unsurprisingly, students who benefited the greatest were those who were most sleep deprived at the start of the study.

The lead author, Julie Boergers, a sleep expert, said:

“Sleep deprivation is epidemic among adolescents, with potentially serious impacts on mental and physical health, safety and learning. Early high school start times contribute to this problem. Most teenagers undergo a biological shift to a later sleep-wake cycle, which can make early school start times particularly challenging. In this study, we looked at whether a relatively modest, temporary delay in school start time would change students’ sleep patterns, sleepiness, mood and caffeine use.”

The reason that most adolescents are sleep deprived is that they need more sleep than adults, but often don’t get it.

Unlike adults, adolescents need 8.5 to 9.5 hours of sleep per night.

American high schools usually start at 8am and since most teens find it difficult to fall asleep before 11pm, there simply aren’t enough hours in the night.

Julie Boergers continues:

“The results of this study add to a growing body of research demonstrating important health benefits of later school start times for adolescents. If we more closely align school schedules with adolescents’ circadian rhythms and sleep needs, we will have students who are more alert, happier, better prepared to learn, and aren’t dependent on caffeine and energy drinks just to stay awake in class.”

This is far from the first study to suggest that early school start times have adverse consequences.

Others have found links between early start times and reduced academic performance, lower mood (as in this study) and even more car crashes.

The evidence seems overwhelming, but later start times remain controversial.

A common complaint is that later starts leave less time for extra-curricular activities.

However, there was no evidence of this in the current study, with students engaged in athletics and other activities for the same amount of time as before.

In addition, instead of being exhausted in the evening, they had more energy to complete their homework.

→ Related: 10 Sleep Deprivation Effects.

Image credit: Dan Woods