Not so much as there is still logic going on and a continual flow.
Spaghetti code is more like jumbled code, which is usually due to unnecessary complexity and tangled controls.
Also, the more people working on a project, the greater the chances for spaghetti, unless there are rules and structures already set in place.
One Big indicator if your code is spaghetti or not is to look at it and realize going through the source code is a lot like going through a labyrinth... minotaur and all...
For example, the guy we recently let go, his source code was atrocious. He used classes, yet not in an object oriented way, at the same time using functions. Inside his classes he would still push all variables through parameters of functions or set them globally and grab them back in. His naming convention would change line by line to whatever he felt like using, examples (from same class): im_updateStatus, clearStatus, clear_history().
Also, Spaghetti code isn't exclusive to PHP, it's for any programming language.
For more info: http://en.wikipedia.org/wiki/Spaghetti_code