There's a certain amount of difficulty that is to be expected when deciding to take up a PhD. However, there is one miserable cost that is not commonly talked about.

In a piece for Quartz by Jennifer Walker, she revealed details about how miserable she became during the third year of her PhD program. One night, she described, she sat on the bed with tranquilizers and a bottle of vodka.

She was planning to end her life. Fortunately, she was able to call her friend. The next morning, she decided to go see a therapist and considered quitting her PhD program.

"The days I spent pursuing my PhD in physics were some of my darkest," Walker wrote. "It wasn't the intellectual challenges or the workload that brought me down; it was my deteriorating mental health."

She described her feelings of isolation and uncertainty. She drank, cut herself and wanted to die.

There are a lot of people struggling with mental health issues in universities across the nation. According to Inside Higher Ed, a study at the University of California - Berkeley found that 47 percent of PhD students suffered from depression.

The data followed a 2005 study that revealed how 10 percent of PhD students contemplated suicide. Moreover, among the PhD students, the highest rate (64 percent) of depression was found in those in the arts and humanities fields.

"I assumed and hoped that simply taking antidepressants and just 'working harder' would help enough," a PhD student in biology who's been diagnosed with anxiety and depression said. "And when things did not quickly improve, this further affected my mood."

Isolation and the Impostor Syndrome are also common feelings among PhD students. There are concerns that these issues can have a much larger impact on students who don't have the right support system.

Several colleges and universities have provided support for graduate students. There are also non-profit organizations like Active Minds and the Jed & Clinton Health Matters Campus Program that can help these students.