Special interest (autism)

Special interests are highly focused interests common in autistic people. Special interests are more intense than typical interests, such as hobbies, and may take up much of a person's free time. A person with a special interest will often hyperfocus on their special interest for hours, want to learn as much as possible on the topic, collect related items, and incorporate their special interest into play and art. Some interests are more likely to be seen as special interests if they are particularly unusual, specific, or niche. Autism rights advocates and psychologists say this binary of acceptable "passions" and pathologised "obsessions" is unfair. Terms like circumscribed interests, obsessions, or restricted interests have historically been used to describe special interests, but these terms are discouraged by autism rights advocates.

Special interests are sometimes confused with hyperfixation. Hyperfixations are short-lived periods of strong interest in a subject over a few days to months which can occur in anyone (although are especially common in people with ADHD), while special interests are an autistic trait and usually last years. A person may hyperfixate on a special interest.

Occurrence and development
Around 75–90% of autistic people develop a special interest, with some studies claiming as high as 95%. Special interests are often developed between one and four years of age but may not develop until adulthood. Many special interests start in children as a fascination with a particular object (e.g. Thomas the Tank Engine) and later develop into an interest in a specific topic (e.g. trains). A special interest may change over time or last a person's whole life. A 2014 survey found that the average number of special interests an autistic person has is 2, and the average longevity is 13 years.

Special interests in autistic people were first written about in 1943 by Leo Kanner as a trait of classic autism and a year later by Hans Asperger when writing about Asperger syndrome. Special interests were later one of the traits listed when autism first appeared in the DSM-3 in 1980. In 2024, special interests are listed as a diagnostic trait of autism in the current DSM-5-TR, described as "highly restricted, fixated interests that are abnormal in intensity or focus (e.g., strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interests)".

Common areas of special interests are transportation, animals, sports, and popular culture.

Engagement
Engaging in special interests can bring autistic people great joy and many autistic people spend large amounts of time engaged in their special interest. In adults, engaging with special interests has been shown to have positive outcomes for mental health, self-esteem, and can be used to manage stress.

Special interests can sometimes interfere with other areas of a person's life, such as school. In children, incorporating a child's special interest into their education has been shown to improve learning outcomes, increase attention on learning topics and teach behaviours such as sportsmanship. Students have been shown to write better when writing about their special interest compared to a control topic. A 2022 study showed 25% of autistic people who worked had employment in their area of special interest and that adults with employable special interests may have better employment outcomes. Special interests may lead people to become child prodigies or savants in their area of interest.

Social interaction
Encouraging discussion of a special interest can help autistic people develop social skills and help them find social communities.

Special interests may lead to social difficulties if the person does not want to discuss any other topic, and conversations may become one-sided especially when infodumping. Some special interests may be more socially acceptable than others, such as an interest in electricity pylons being seen as odder than an interest in horses or football teams. Autistic people who are aware of this may deliberately stop themself from talking about their special interest as a form of masking, especially if they have been mocked for their interest in the past. Special interests may be atypical for a person's age.

Autism acceptance proponents encourage autistic people to embrace their special interests, as long as they are not interfering with other parts of a person's life. Special interests can be used by autistic people as a way to understand the world and allistic people.

Examples
Environmental activist Greta Thunberg has credited her success to her special interests. She explained to The Guardian in 2021, "A lot of people with autism have a special interest that they can sit and do for an eternity without getting bored. It’s a very useful thing sometimes...[if] you feel you have a purpose, then it can be something you can use for good, and I think I'm doing that now".