Spectrum of mental disorders, the features of which include onset during infancy or childhood, preoccupation with subjective mental activity, inability to interact socially, and impaired communication.

Autism.

Explanation:

Autism: In psychology, the term autism is also referred to as autism spectrum disorder or ASD. Autism is defined as a medical condition that is being distinguished based on a child's challenging social skills, nonverbal communication, speech, and repetitive behaviors.

Characteristics:

1. Need for sameness.

2. Repeated actions.

3. Problems in interacting with others.

Types: Asperger's Syndrome, Autistic Disorder, etc.

D) Join a weight-loss support group

Explanation: