Does "Lucid Interval" immediately bring to mind medical disorder? I would like to use it as the title for a blog and I don't want people to be put off.
Yes, or possibly severe drug dependence.
I do not, though, know from just seeing it in a title whether you mean it literally or not. Surely the reason for using it as a title is that you are either writing about mental disorder, or referencing it metaphorically (perhaps in suggesting the blog itself is a brief patch of sanity).
Yes, of course it implies that you've got Alzheimer's or dementia praecox, but that from time to time you manage to see the world as it is (a meaningless phrase, of course, because we all see the world only as we perceive it, not as it really is) and then spring to your PC, put on your thinking cap, and tap out your thoughts for posterity.
No need to worry about that though. I just read the title of a recent blog on the NY Times website that said something about defining humanity (that is, the state of being a member of the species homo sapiens sapiens) as an incurable disease.
Because most people hate to think, and because even those who love to think can't do it all the time, most of the time our minds are not lucid. We all have to make an effort to be be lucid (clear and unambiguous), so I think your blog title is perfectly reasonable. It wouldn't put me off. Only the content will force me to make a judgment about whether to read it. In fact, I'd be interested in reading something so honest.