Autism spectrum disorder (or autism) refers to a range of lifelong developmental conditions that affect how people see the world and interact with others.  Because autism is a spectrum disorder, each person with autism has their own strengths and challenges.  These challenges include communication and social interaction, or restricted and repetitive patterns of behaviours, activities or interests.  Some autistic people may also have learning disabilities, mental health issues or other conditions, meaning each person needs a different level of support to learn and develop.  Autism affects around 1 in 100 people  and is estimated to affect three times as many men as women.  Autism is not a disease so it cannot be cured. 
The reason that some people have autism is not completely clear. However, scientists believe that it is most likely related to a person’s genes. There are several different genetic reasons for autism: 
A common myth is that vaccines cause autism, but many scientific studies involving hundreds of thousands of people show that this is not the case. 
Some children show signs of autism from a very young age, but others with milder versions of autism do not show signs until later in their lives, and can sometimes reach adulthood without being diagnosed.  The common signs of autism are listed below. Not everyone with autism will show all of these signs, and some children who don’t have autism may show some of them. 
Early signs of autism in young children include:
By 6 months old
By 9 months old
By 12 months old
By 16 months old
By 2 years old
Signs of autism in older children and adults include: [8,9]
If your doctor thinks you or your child might have autism, they will refer you to a specialist.
The specialist will carry out some assessments to find out if your child has autism. They might include: [10,11]
For the specialist to diagnose you with autism, they need to see that you have struggled with communication, social interaction, and repetitive behaviours or interests since early childhood. They must also see that these difficulties have limited your everyday life. The specialist might ask you to bring along somebody who knew you as a child, such as a parent or older sibling. This is because they will need to ask detailed questions about how you behaved as a young child. 
The most effective therapies for autism are behavioural therapy, occupational therapy, speech therapy, physical therapy, and some medications. 
These therapies focus on understanding how learning occurs and teaching children as young as two years old the basics of communication and social interaction. . A therapist supports a person to change their behaviour based on principles of learning derived from behavioural psychology. The therapy encourages positive behaviours and discourages negative behaviours. In addition, the therapist teaches new skills and helps the person to apply those skills to new situations 
Occupational therapy teaches autistic people the skills to do daily activities that involve movement and coordination.  The therapy focuses particularly on developing skills for movements of the wrists, hands, fingers, feet and toes. These movements are used in daily tasks such as dressing, using utensils, cutting with scissors and writing. For young children with autism, the therapy often focuses on improving co-ordination and ability to do simple tasks. In older children, occupational therapy often looks to improve social behaviour and increase independence.
Similar to Occupational Therapy, physical therapy is used to improve the individual’s ability to participate in everyday activities. Physical therapy teaches and improves skills such as walking, sitting, coordination and balance.
Speech therapy is an important treatment for autistic people, as they have problems with speaking and communicating in social situations.  Speech therapy helps to improve a person’s communication skills, so they can better express their needs or wants.
Some autistic people do not speak at all, and the use of gestures, sign language, and picture communication are often useful tools to improve their abilities to communicate.
There is no cure for autism, and currently there are no medications that treat it directly. However, some medications can help modify some behaviours associated with autism, including irritability, insomnia, aggression and lack of focus.  By reducing these disruptive behaviours, other therapies, such as behavioural therapy, may be more effective. Medication should be prescribed and monitored by a qualified doctor.
People living with autism have complex healthcare needs throughout their life.  Early diagnosis, along with tailored support from a range of healthcare workers, is essential to help autistic people reach their potential and live as normal a life as possible. At the moment, there are no treatments that address the underlying cause(s) of autism, although some medications are effective in treating some of the associated characteristics. However, scientists are learning more about the underlying causes of autism spectrum disorders. This new knowledge is also helping scientists to develop new medications that may be able to modify the changes in the brain that play a role in autism spectrum disorders. Some of these new medications are being tested in clinical trials.