Signs of autism usually appear by age 2 or 3 but the average age for diagnosis is around 4.
Autism is a spectrum disorder in which each person with ASD is affected in different ways. Some may be severely challenged in their learning and communicating and need significant support throughout their lives while others are highly skilled and able to live as adults with very little or no support. People with autism may also be picky eaters, have gastrointestinal issues such as diarrhea or constipation, or have sleep disturbances. About 20% of those with ASD also have seizures, and many have accompanying mental health issues such as ADHD, anxiety, or depression.
Many parents we spoke to suggested watching for communication and developmental delays in your child. This is the age where you may begin to see a bigger gap between children without ASD and your own, especially in social skills. If you suspect your son or daughter may have autism, you will want to discuss it with your family doctor or pediatrician.