Troubled Child

The Troubled Child is an innocent-looking youngster who looks cute enough, until you notice they rarely smile, and tend to talk in a broken deadpan when they talk at all. They may inexplicably burst into tears at times. Usually the cause of their trouble is Parental Abandonment or a congenital impairment of some sort.

Has excellent Woobie potential, but if the writers go too far, they may end up as The Scrappy for less "compassionate" viewers. Opposite of the Cheerful Child. Compare Creepy Child, and don't confuse with Bratty Half Pint. Compare Lonely Rich Kid.

Film

 * Newt in Aliens.
 * Most kids in Shyamalan movies.

Live Action TV

 * Luka, an orphan the team was sent to rescue in "The Stork Job" in Leverage.
 * Most kids in The X Files.
 * Except the creepy homicidal ones.
 * Cassandra when she first appeared on Stargate SG-1. The show lasted long enough for us to see her grow out of it and become a normal (i.e. rather bratty) teenager.
 * Tomoya from Aishiteru.

Manga and Anime

 * Fard from Space Runaway Ideon. Like most of the other kids,  Spends most of his time, moping, cries easily and carries a rag doll with him for most of the series.
 * Emile of Count Cain, due to Parental Neglect, mainly.
 * Natsume Yuujinchou is about a Troubled Child finally getting a chance to recover from past trauma he's dealt with.
 * Shinji Ikari from Neon Genesis Evangelion. Along with most of the cast, for that matter. It Gets Worse.
 * Yuu from Noein. At the beginning of the series it's quite clear he's on the edge of a severe nervous breakdown due to the extremely controlling nature of his mother. Once his mother gets some sense talked into her and eases up, he starts to slowly improve.

Theatre

 * Winthrop in The Music Man, described by his older sister Marian as "a problem child who can't understand why his father was taken away." He lisps when he talks, too.
 * Zoe in Quidam, a lonely adolescent girl who feels alienated from everyone, including her parents. Her journey into a Magical Land shows her that everyone feels this way sometimes, and how she can connect/reconnect with others.

Tabletop RPG

 * In the Shadowrun adventure Divided Assets, the PC's are hired to kidnap a young boy named Shawn Gaffney. After doing so, they discover that Shawn has psychological problems due to emotional neglect by his parents.

Western Animation

 * Link from the Daria movie Is It Fall Yet? came out somewhere between this and a Mouthy Kid--he was clearly miserable (by his own admission) due to a difficult home life, but his attitude was less depressed and more angry as a result.
 * The titular character herself. Though more accurately a troubled teen, she had no interest in social interaction even as a child.