It is common for most children and teens to have one or two things they are very interested in. Your child may be interested in Star Wars and want to decorate his room in this theme, collect all the figures, wear the pajamas, read the books, watch the movies over and over, collect the cards, and dress as one of the characters for Halloween. Is he an enthusiastic collector or a disordered child? It is hard to know where to draw the line.
On one hand, a special interest that interferes with a child’s ability to interact with others is surely a problem. If he can talk about little else, is insistent that his peers play only his special interest, and refuses to do schoolwork unrelated to his special interest, then it has crossed over from an enthusiastic hobby to a problem. On the other hand, if a special interest provides a great source of pleasure, increases knowledge, and enhances self esteem, it can be hard to actually say it is a problem. Behaviors are usually determined to be a problem if they interfere with functioning. Your child’s interest may provide a mixture of problems and pleasure.