Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by persistent deficits in social communication and restricted, repetitive patterns of behavior, interests, or activities. The disorder, as specified in the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), combines previous diagnoses of autistic disorder, Asperger’s disorder, and pervasive developmental disorder. Since these previous diagnoses differ greatly in severity, ASD covers a wide range of deficits. Some people with autism spectrum disorder cannot handle everyday social interactions while others may be far less affected.
In terms of social deficits, sufferers may have difficulty reciprocating both socially and emotionally in back-and-forth conversations. Their nonverbal communication, such as eye contact, body language, and facial expressions, may be impaired. They also may not be able to develop, maintain, and understand social relationships. People with autism spectrum disorder typically have few close friends.
Repetitive patterns may include motor movements, use of objects, or speech. A child may line up toys or repeat what others say. People with autism spectrum disorder may prefer rituals and be inflexible to even small changes. They may have highly restricted, fixated interests such as preoccupation with unusual objects. Furthermore, they may have abnormally high or low reactivity to sensory aspects of their environment. For instance, they may be indifferent to pain or smell objects excessively.
Prevalence of autism spectrum disorder has approached 1% of the US population in recent years, with similar rates among children and adults. It is unclear whether the cause is the expansion of diagnostic criteria, increased awareness, or true increase in risk.
Symptoms typically start to appear during the second year of life but may be present earlier or later depending on the level of severity. Caregivers usually report noticing a gradual or rapid deterioration of social or language skills. Autism spectrum disorder does not get worse over time. Most people with ASD start to learn compensatory strategies during adolescence and adulthood. However, only a minority of adults with autism spectrum disorder can live and work independently. These individuals typically have high language and intellectual abilities and are able to find a niche that matches their special interests and skills.
The cause of autism spectrum disorder is not very well understood. Some environmental risk factors include advanced parental age, low birth weight, and fetal exposure to valproate. Twin studies have established heritability rates ranging from 37% to over 90%. Currently, 15% of ASD cases are associated with a genetic mutation, with many inter-family differences. Despite some parental suspicions and celebrity endorsements, there is no scientific evidence that links vaccines to autism spectrum disorder.
Individuals with autism spectrum disorder are markedly impaired against their cultural norms. Cultural and socioeconomic factors may impact time of diagnosis. In the United States, ASD may be under-diagnosed or diagnosed late in African American children. Boys are four times as likely as girls to be diagnosed with autism spectrum disorder. Girls with ASD tend to show intellectual or language impairments. It’s possible that many autism spectrum disorder cases in girls go unrecognized because of subtler presentation of symptoms.
Autism spectrum disorder is frequently associated with intellectual disabilities, learning disabilities, language disorders, and other psychiatric disorders. It also commonly co-occurs with medical conditions, such as epilepsy, sleep problem, constipation, and avoidant-restrictive food intake disorder.
There is no proven cure for autism spectrum disorder, but research has supported the effectiveness of early childhood interventions in reducing symptoms. These interventions include a variety of skill-based behavior therapies, such as verbal or social skill training. Medications, such as antipsychotics risperidone (Risperdal) and aripripazole (Abilify), can help reduce irritability in children ages 5 to 16 who have ASD. Doctors may also prescribe other medications for off-label usage.