What If Depression Actually Causes Other Diseases?

depression treatment

What If Depression Actually Causes Other Diseases?

This weeks post is contributed by Anne Freier, writer and editor focusing on science, psychology, the environment & technology.

“When it happens, I just want to be alone. It’s like cancer eating through my soul, a deafening silence, the absence of all that once felt good or right.” I asked a friend what depressive disorder felt like; this was her answer.

Over 300 million people suffer from depression, making it one of the most common mental disorders worldwide. Nearly 800,000 people die from suicide each year and although treatments exist, just 10% of patients receive care for depression.

People who live with major depression often describe it as a “dull” or “numb” sensation. Some say they feel “trapped”; as if they’re “drowning”; they’re controlled by their thoughts. For others, it is nothing but “darkness”.

Depression can have a profound effect on the lives of sufferers, their partners, and families. And as if the emotional burden wasn’t enough, depressive disorder may be a risk factor for several other conditions.

For the first time, researchers have identified a causal link between depression and 20 other diseases based on genetic evidence. Scientists at the Australian Centre for Precision Health at the University of South Australia Cancer Research Institute analyzed the genetic risk scores for depression and 925 diseases in over 330,000 individuals. Their findings are ground-breaking.

“This research puts the ‘chicken and egg’ conundrum to rest, showing that depression causes disease, rather than only the other way around,” explains Anwar Mulugeta, the lead author of the paper published in Molecular Psychiatry.

It’s a question that experts have asked themselves before: could mental diseases cause physical conditions? There is evidence to support their suspicion, but the problem with most existing studies is that they focus on a single illness or assume that physical illness causes depression instead of the other way around.

Mulugeta used a method called Mendelian Randomisation phenome-wide association study (MR-pheWAS). It’s a bit of a mouthful, but the important thing about this method is that it allows them to study whether depression genes could play a role in other diseases. What’s special about the study is that it didn’t require an assumption; that is, the team didn’t have to choose a specific disease to study but were able to look at a large range of conditions.

“Our results suggest that it is important to look beyond the obvious and that we need to screen and effectively manage depression-related co-morbidities if we want to minimize the longer-term negative implications on health,” says Professor Elina Hyppönen, director of the Australian Centre for Precision Health. Among the 20 diseases causing depression are: anxiety and sleep disorders, Parkinson’s disease, heart disease, gastrointestinal issues, asthma, and even osteoarthrosis.

The connection between depression and anxiety isn’t surprising, given that half of patients with depression say they also suffer from anxiety. Gastrointestinal conditions could arise “due to side effects from medications used to treat depression”. Perhaps more astounding is the finding that depression can cause lipid metabolism disorders (e.g. hypercholesterolemia), ovarian cysts and asthma.

For Hyppönen and her team, the discovery has huge practical implications. If doctors can screen for associated conditions in depressed patients, they will be able to provide better treatment plans. “The more we can look at the individual patient as a whole, the better their outcomes are likely to be,” she said. In the U.S. alone, the indirect and direct costs of depression exceed $210 billion per year. We know that depression is on the rise. Worldwide, depression rates have increased by 18% between 2005 and 2015.

But what’s fuelling the hike in depressive disorders? Aside from genetics and major life events such as the death of a loved one or having a child, depression may have increased with modernization. Poor diet, inactive lifestyles, sleep deprivation or a lack of sunlight, isolation, and increased competition with others all play a role in what some epidemiologists label a ‘depression epidemic’. Or maybe we’ve just become better at diagnosing the illness?

At the same time, the disorder has surged in younger people. Depression rates have shot up to 15% among those born around the millennium, compared to 9% among children born in the 1990s. Young or old — the societal factors fuelling the surge are the same: weaker relationships in less tight-knit communities or the insatiable drive to earn money and seek fame. Have we exhausted the limit of our self-expectation? The social media image and comparison factor aren’t helping. How do we expect to feel after we spend hours scrolling through photos of those who are seemingly better than us on Instagram? Dissatisfaction abounds.

But there are no quick fixes. Medication and therapy are often unavoidable to treat major depression. Physical exercise and a healthy diet can be mood-stabilizing. And it’s important to speak to others because the isolation that comes with feeling depressed can make matters worse.

If you need help or would like to speak to someone, you can reach out to the depression helplines below.


National Suicide Prevention Lifeline: 1–800–273–8255 (TALK)

The Samaritans: 877–870–4673 (HOPE)

Trevor Project Lifeline (a hotline for LGBT youth) 866–488–7386

Child Help USA National Hotline 1–800–422–4453


Mind 0300–123–3393

Samaritans 116–123

SANE 0300–304–7000

YoungMinds 0808–802–5544


Beyond Blue 1300–22–4636

SANE Australia 1800–18–7263

Kid’s Helpline 1800–55–1800

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