I am a 3rd year PhD student in cancer research. During the past two and half years, I get bored about my PhD project and gained more and more interest in neuroscience (I won't explain the how-come here). I was not sure whether I would get bored in neuroscience again (just as I did in cancer biology), so I took courses online in basic neuroscience, neural imaging, etc and read research papers and some textbooks. I also learned some programming. Now I somewhat live a lifestyle that constantly switch modes: I studied about my PhD project in daytime and as soon as I left lab, I was eager to learn more about neuroscience.

Recently, the "quitting" thoughts come again and again. My reasons for quitting is: 1, I am not excited about cancer research at all, I feel boring having to do this in daytime, I've got eagerness to study neuroscience. 2, I think doing things I am not keen on is wasting my time. 3, I am worried that I would not get a good job in neuroscience after I graduate this PhD in cancer research.

My friends persuaded me not to --- they think it would be alluring to graduate with a PhD at the age of 25. But the thing matters is not the PhD diploma itself, what matters is what I did for the PhD diploma, right?

But at the same time, I was also afraid of quitting. It would not be easy to find another PhD in neuroscience. Thinking only about getting recommendation letters for application is already a headache.

Have you ever been in the same situation or have any suggestions?