Communication: Limited babbling or cooing, does not respond to their name by 12 months, lack of gestures such as pointing or waving by 12–14 months, delayed speech development or no meaningful words by 16 months.

Social Interaction: Limited eye contact with caregivers, lack of interest in social games (e.g., peek-a-boo), appears indifferent to people or avoids interactions, does not smile in response to others by 6 months.

Behavioural Patterns: Repetitive movements like hand-flapping or rocking, fixation on specific objects (e.g., staring at a spinning fan), unusual responses to sensory input such as overreaction to sounds or textures.

Communication: Difficulty combining words into phrases by age 2, repeats phrases (echolalia) instead of answering questions, unusual tone of voice such as monotone or robotic speech.

Social Interaction: Prefers playing alone rather than engaging in parallel or cooperative play, limited imaginative play or difficulty understanding pretend scenarios, does not seek comfort from caregivers when upset.

Behavioural Patterns: Rigidity in routines and difficulty with transitions, strong interest in specific topics or objects (e.g., obsession with trains or letters), repetitive play patterns such as lining up toys.

Communication: Difficulty initiating or maintaining conversations, trouble understanding jokes or sarcasm, talks excessively about a narrow area of interest without recognising others’ lack of interest.

Social Interaction: Struggles to make or maintain friendships, may appear unaware of others’ emotions or social norms, difficulty sharing or following group rules during play.

Behavioural Patterns: Extreme distress over small changes in routines, repetitive motor movements such as pacing or spinning, sensory sensitivities (e.g., avoiding certain clothing textures or food types).

Communication: Difficulty adjusting language to different social contexts, may come across as blunt or overly literal, challenges in understanding abstract language or implied meanings.

Social Interaction: Limited or superficial friendships, avoidance of social interactions due to anxiety or misunderstanding social cues, difficulty interpreting non-verbal communication like facial expressions.

Behavioural Patterns: Intense focus on niche interests or hobbies (e.g., memorising facts about a specific topic), repeatedly talks about their interests to the exclusion of other topics, significant sensory issues such as discomfort in noisy or crowded environments, reliance on routines and rituals to manage anxiety.

Communication: Difficulty with small talk or casual conversations, challenges interpreting humour, sarcasm, or social nuances, may be perceived as overly direct or rigid in speech.

Social Interaction: Struggles with forming or maintaining close relationships, discomfort or fatigue in social settings, difficulty recognising unwritten social rules or workplace dynamics.

Behavioural Patterns: Intense focus on specialised interests that may influence career choices, sensory sensitivities to lights, sounds, or textures, strong preference for routines and predictability, reliance on coping mechanisms to navigate overwhelming environments.