Special interests are highly focused interests common in autistic people.^[1]

Special interests are more intense than typical interests, such as hobbies,^[2] 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,^[3] collect related items,^[4] and incorporate their special interest into play^[5] and art.^[6] Some interests are more likely to be seen as special interests if they are particularly unusual, specific, or niche.^[2] Autism rights advocates and psychologists say this binary of acceptable "passions" and pathologised "obsessions" is unfair.^[7][8] Terms like circumscribed interests,^[9] obsessions, or restricted interests^[10] have historically been used to describe special interests, but these terms are discouraged by autism rights advocates.^[7]

Special interests are sometimes confused with hyperfixations.^[11] 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),^[12] while special interests are an autistic trait and usually last years.^[13] A person may hyperfixate on a special interest.

Around 75–90% of autistic people develop a special interest,^[4] with some studies claiming as high as 95%.^[14] Special interests are often developed between one and four years of age but may not develop until adulthood.^[4] 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).^[2] A special interest may change over time or last a person's whole life.^[15] A 2014 survey found that the average number of special interests an autistic person has is 2, and the average longevity is 13 years.^[2]

Intense special interests were written about by French psychiatrist Jean-Étienne Dominique Esquirol in 1827.^[16] They were tied to a condition today considered autism by Soviet child psychiatrist Grunya Sukhareva (Груня Сухарева) in 1925.^[17][18][19] In November 1940, Lauretta Bender and Paul Schilder published a paper focused on the topic.^[20] Bender and Schilder's contemporaries like Hans Asperger and Leo Kanner also wrote about the matter, which was important to the development of autism awareness.^[21]

Special interests were later one of the traits listed when autism first appeared in the DSM-III in 1980.^[2] 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)".^[22]

Common areas of special interests are transportation, animals, sports, and popular culture.^[23]

Engaging in special interests can bring autistic people great joy^[24][25] and many autistic people spend large amounts of time engaged in their special interest.^[26] In adults, engaging with special interests has been shown to have positive outcomes for mental health,^[27] self-esteem,^[28] and can be used to manage stress.^[23]

Special interests can sometimes interfere with other areas of a person's life, such as school.^[29] In children, incorporating a child's special interest into their education has been shown to improve learning outcomes,^[30][28] increase attention on learning topics^[31] and teach behaviours such as sportsmanship.^[32] Students have been shown to write better when writing about their special interest compared to a control topic.^[33] 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.^[26] Special interests may lead people to become child prodigies or savants in their area of interest.^[23]

Encouraging discussion of a special interest can help autistic people develop social skills^[23] and help them find social communities.^[34][35]

Special interests may lead to social difficulties if the person does not want to discuss any other topic, and conversations may become one-sided^[2] especially when infodumping.^[36] 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.^[23] Autistic people who are aware of this may deliberately stop themselves from talking about their special interest as a form of masking,^[23] especially if they have been mocked for their interest in the past.^[14] Special interests may be atypical for a person's age.^[2][37]

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.^[38] Special interests can be used by autistic people as a way to understand the world and allistic people.^[39]

Environmental activist Greta Thunberg has credited her success to her special interests.^[40][41] 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".^[42]