Infants (0-12 months)

In the early months, signs of autism can be subtle, but some behaviors to watch for include:

• Lack of eye contact: Babies typically make eye contact by 3 months, but infants with autism may avoid eye contact altogether.
• Limited social smiling: By 6 months, most babies smile in response to faces and social interactions. Infants with autism may show less interest in social smiles.
• Delayed response to name: By 6 months, babies should begin to respond to their name. If a baby consistently doesn’t respond or seems unaware when called, it could be an early sign of autism.
• Limited gestures: Most babies begin using hand gestures like pointing or waving by 9 months. A lack of these gestures might indicate a developmental delay.

Toddlers (1-3 years)

As children approach toddlerhood, more obvious signs of autism may emerge. By the time kids are around 18-24 months, you may notice:

• Delayed speech and language development: Many toddlers with autism may not speak at all by the age of 2, while others may have difficulty with conversations.
• Repetitive behaviors: Children with autism may start to engage in repetitive activities, such as hand-flapping, rocking, or spinning objects. These behaviors often emerge around age 2.
• Limited social engagement: A toddler with autism may prefer solitary play over interacting with others. They may also have difficulty understanding social cues or playing pretend games.
• Narrow interests or routines: A child with autism may exhibit intense interest in a specific toy or activity, and may become upset if their routine is disrupted.

Preschoolers (3-5 years) 

By the preschool years, more defined behavior patterns related to autism may be evident. When do kids show signs of autism in this stage? Key behaviors include:

• Difficulty with pretend play: Children with autism may struggle with imaginative or pretend play, often preferring repetitive activities or sticking to routines.
• Difficulty with peer interaction: Preschoolers with autism may find it challenging to make friends or understand social rules like taking turns or sharing.
• Sensory sensitivities: Many children with autism have sensitivity to lights, sounds, textures, and smells. They may become overwhelmed or distressed by stimuli that other children can tolerate.
• Speech and communication delays: While some children with autism may develop language skills at a normal pace, others may experience speech delays or struggle with understanding language nuances like jokes or sarcasm.

School-aged children (6-12 years) 

As children enter school, the signs of autism may become more apparent in social and academic settings.

• Social Isolation: School-age children with autism may have trouble making friends or understanding social norms, which can lead to feelings of isolation.
• Difficulty with Nonverbal Communication: Understanding facial expressions, body language, or tone of voice may be difficult for children with autism, leading to misinterpretations or awkward interactions.
• Academic Challenges: Children with autism may excel in certain areas, such as math or memorization, but struggle with others, like reading comprehension or problem-solving, due to their difficulty with abstract thinking.
• Repetitive or Ritualistic Behaviors: Some school-age children may continue to engage in repetitive behaviors, like arranging objects in a specific order or following rigid routines.