Google has released three photography apps. ( Picture: AP)

Once upon a time, your first port of call for health-related queries would’ve been a doting family member, or a wise old friend.

These days, all it takes is a quick visit to Dr Google and we’ve got ourselves a speculative diagnosis, which is all any internet user can hope for in the current digital climate.

So, what were the most commonly searched topics in 2017?

According to a CNN analysis of health-related “what” and “why” questions as provided by Google Trends, some of the most popular searches in the US were on addiction, opioids and the Netflix series 13 Reasons Why.

The data was collected from January to mid-December and revealed that the ketogenic diet quadrupled in searches this year and was one of the most-Googled health topics.

The popular diet was initially developed for people with epilepsy in the 1920s and its revamped version involves eating a low carbohydrate, high fat diet that supposedly kickstarts the body’s fat-burning processes.

People were also keen to find out about opioids, presumably in light of America’s “opioid epidemic” that made headlines in October.

"Nobody has seen anything like what is going on now," President Trump said at the time, when he declared the crisis a national public health emergency as it was revealed that more than 2 million US citizens are dependent on abusive substances.

Hence, “what is opioid addiction?” became a popular search term.

Interestingly, Netflix’s TV series 13 Reasons Why also prompted a flurry of searches.

The controversial program, on which Selena Gomez was an executive producer, told the fictional story of a teenager who takes her own life and leaves a series of audio tapes for her classmates to listen to posthumously.

The series provoked a number of concerns regarding its romanticisation of suicide and was criticised by mental health experts as being triggering for those with pre-existing suicidal thoughts.

CNN’s research revealed that the show, which has been renewed for a second season, also provoked a spark in searches related to suicide awareness and prevention.

Another possible Selena Gomez-related search term was “what is Lupus?”, the autoimmune disease which came into the spotlight after the US singer had a kidney transplant thanks to her two-year-long battle with the condition.

Other issues people sought Dr Google’s help with included "what causes hiccups?", "how to stop snoring" and "what is ADHD?".

As for the most popular “why” health-related topics, 13 Reasons Why came out on top, followed by “why is addiction a disease?”, “why is the roof of my mouth sore?” and “why is apple cider vinegar good for you?”.