Graphology is the study of handwriting with the goal of learning more about the writer. It is important to distinguish graphology from forensic document analysis, because although both involve the analysis of handwriting, different methods are employed, and the end goal is different. Graphology focuses on the psychology of the author, while forensic document analysis is meant to determine the origin of a document to learn whether it is valid or not. The two require radically different fields of study, and are approached from unique perspectives.
Graphologists believe that handwriting can reveal a great deal about the psychological state of the author. Examining handwriting is supposed to allow the graphologist to probe into the depths of the author's subconscious. A graphologist looks at things like the angle of the letters, the slant of the writing on the page, the pressure, and the shape of the letters. For example, many graphologists believe that hard pressure indicates anger or emotional distress, or that letters which trail off at the end of the line indicate mental instability.
The idea behind graphology is that the subconscious often bubbles through in writing. By looking at how people use language and how they write, a trained examiner is supposed to be able to draw conclusions about the author. However, many scientists believe that graphology is a dubious enterprise at best, and evidence from graphologists is often ignored in criminal cases, due to a preference for more scientific fields of inquiry.
Although graphology's ability to probe into the depths of the mind is questionable, this form of handwriting analysis actually can be useful. Doctors sometimes look at the handwriting of patients to learn more about the health of their central nervous systems, especially if writing samples for comparison are available. A decline in the quality of handwriting can suggest that someone is having difficulty controlling his or her hands, which might mean that a central nervous system condition like Parkinson's is beginning to manifest. Difficulties in forming words or writing coherently can also indicate problems with the central nervous system, or suggest that a patient is experiencing emotional unrest.
Employers may also attempt to use graphology, although this practice has been called into legal question in some regions of the world. Reviewing the handwriting of potential employees may be reasonable from the perspective of someone who wants employees with neat handwriting who can pull language together well on the fly, but choosing not to hire someone because he or she writes at a leftward slant or makes narrow letters could be considered discrimination.