Why do rates of suicide increase in the spring?

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In 2013, almost 850,000 people died of suicide worldwide, and it’s among the leading causes of death among young people.

The fact is that springtime — when the days are getting longer, the weather is getting warmer, and nature is coming back to life — is just when rates of suicide begin to rise.

Every year, these rates actually peak in mid-spring, which is May in Northern hemisphere countries including Canada and November in countries in the Southern hemisphere.

We know that decreasing daylight hours in the fall and winter leads to worsening depression in many people, which is called seasonal affective disorder.

And rates of depression do go up at that time of year, and especially over the Christmas holidays.

But the commonly-held belief that suicides peak during the holiday period is actually a myth. In North America, December actually tends to be the lowest month for actual suicides.

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So why is spring so much more dangerous?

Studies have shown that so-called bioclimactic factors such as increased sunlight, temperature, and humidity are associated with suicides.

Now, as doctors, we’ve known for years now that the risk of suicidal behaviour in young people with depression paradoxically rises in the first one or two months after starting antidepressants.

This is believed to be due to the fact that antidepressants can increase energy before they actually improve mood, giving patients the energy and will to actually act on their suicide plan, before the medication can become fully effective.

And we know that for example sunlight can affect the release of several hormones that have been implicated.

In depression, including the sleep hormone melatonin and the neurotransmitter serotonin in the brain.

So the boost of sunlight in the spring might be doing something similar to that dangerous initial boost provided by antidepressants.

But there’s another interesting theory which has recently gained traction. That is that seasonal allergies might actually be playing a role in these suicides.

Studies have shown that seasonal peaks in pollen levels are closely linked to suicide rates, and to symptoms of anxiety and impulsivity.

We also know that allergens create inflammation, which involves the release of substances called cytokines, which can have various effects on both neurotransmitters and the brain itself.

It’s also worth noting that some of the medications used to treat severe allergic symptoms also have side effects that include mood disturbance and suicidal thoughts.

So for most of us, spring evokes joy and a new sense of purpose, but if you do have friends or loved ones who are suffering from depression, spring is also a time when they may be most in need of your support.