• Unusual or special interests can develop as early as age two to three years and may commence with a preoccupation with parts of objects such as spinning the wheels of toy cars, or manipulating electrical switches. The next stage may be a fixation on something neither human nor toy, or a fascination with a specific category of objects and the acquisition of as many examples as possible. A subsequent stage can be the collection of facts and figures about a specific topic.
• In the pre-teenage and teenage years the interests can evolve to include electronics and computers, fantasy literature, science fiction and sometimes a fascination with a particular person.
• The interest can be a source of enjoyment, knowledge, self-identity and self-esteem that can be constructively used by parents, teachers and therapists.
• One of the distinguishing characteristics between a hobby and a special interest that is of clinical significance is an abnormality in the intensity or focus of the interest.

Information courtesy of Professor Tony Attwood.