Graphology developed along a few independent methods. Nowadays the situation can thus be described:

The French/european method

The specificity and strenght of the french/european method rests in the global and simbolic approach to handwriting, which is integrated only in a second step by an analytic one.
Handwriting is not seen as a neuro-psycho-biological byproduct†, but first and foremost as the result of the "directive image".

In this pdf (italian only) one can find a brief introduction to Graphology according to the French/european school.

It is also that, and as such it must be studied when necessary. In forensic graphology, for instance.