Personally, I think a 'self help' topic would be time & effort well spent, myself, I have tried both kind of topics, a novel, then, quite a few successful 'books & articles' aiding others in quite a few topics of helping them within their predicament.
My experiences, you must have heard folk all over the globe, in fact, worldwide, they say 'Hey Dale, (obviously in various languages) ya know, we all got a story inside of us just oooozzzzing, itching to break out into the limelight for others to hear' & who am I to argue with what they all got to say, probably, because I'm over powered by so many 'right' people so, eventually, I actually did finish one of my 'true horror' stories titled, "Sarah, Expect The Unexpected" (THIS IS NOT A PLUG) that I began some time ago & thus, eventually, a few months ago, self published the book on Amazon, but, my experiences in writing, & my enthusiasm to show what I know are more concentrated on self help issues, as so many of us need to find a 'personal' solution to our problem, find the problem, then offer the remedy.
Find your niche because writing takes your time & mucho effort, you do get involved, on a physically demanding, spiritual & emotional level, especially if you enjoy (know much about) the topic you are authoring.
Also, I found that creating a novel, became more taxing on my mind until one day, finished, published, unpublished, re-edited, then re-published (then this whole cycle once again) until one day. Self published for sure Yippeeee!
Good luck in your quest pursuitofmind & remember, whilst your thinking about it, YOUR NOT DOING IT, so my friend, join the many happy souls that are now published authors, there definitely is room for you too, WE ARE WAITING.
Regards Dale Ovenstone