The Function of an Opening Sequence

It's Kind of a Funny Story

It's Kind of a Funny Story - IMDb

It's kind of a Funny Story is a dark comedy based on a book by Ned Vizzini of the same name. The story follows a teenager called Craig, who admits himself into a mental health hospital after contemplating suicide, and also about the people he meets on his way to recovery.

It was produced by various production companies such as Focus Features and Warfare Entertainment. The production companies are shown before the opening sequence begins.

The opening film begins with the narration of the main character, fading into the first shot of someone cycling across a bridge. Looking at the use of Mise-en-scène you can tell that the film is set in the present by the use of the character's modern looking clothes and the setting of the city in the background. The audience knows that this is the beginning of the story by the introduction of the main characters dialogue:

 "It starts on a bridge".

From the opening sequence a sense of character is created for the characters we see, shaping our impressions of them later on. The main character is the boy walking across the bridge, this is shown by his opening narration, and that the camera focuses mainly on him. We are shown that he's depressed and trying to kill himself, this is because he climbs up onto the bridge walking over the cars and the traffic below.

The audience are also given the impression that he's quite an awkward character, this is by his appearance and the way he talks to his family whilst on the bridge, stuttering as he speaks to them:

"I'm - I'm trying to kill myself!"

We learn that the characters talking to him are his family, and by the way they are talking to him - showing little concern of him and more of his bike shows they are quite pushy, which is shown later on in the film. A connotation of their attitude could be the reason the main character is depressed.

However their characters add the comedy element of the film by their conversation. This helps the audience to classify the film as a dark comedy, because it's funny but at the same time there are elements in the film that ordinarily would be considered as quite serious, such as the main character trying to commit suicide.

The basic plot of the story is also given in the opening sequence. From this you learn the main character is depressed and trying to commit suicide, possibly due to his family. However near the end of the sequence he falls by accident into the river below and the scene is revealed to be a 

dream by his narration:

"This is usually where I wake up in a sweaty panic, but this time was different." 

At the end of the sequence the shot fades followed by the narration of the main character, leaving the title of the film on the screen.

In short the function of this opening sequence, and all opening sequences in general, is to introduce a film which helps to engage the audience so they stay in their seats to watch it. If the opening sequence is bad, audience expectations would be pretty low.
An opening sequence introduces characters and narration, helping the audience to gain an insight into what the story is going to be about; giving you information in the first few minutes on the general plot and ideas of the film. An opening sequence is also used to set the time and the place for the film, further helping to set the scene. Using sound the producer of a film is able to make a film more recognisable, setting the audience up for a certain part of the plot or to create tension, such as the sound in the opening sequence of It's Kind of a Funny Story. 
An opening sequence is also used to introduce the genre of the film, it can do this by all of the features above. For example, a comedy could have lighthearted music and narration, showing a funny sequence of the film so audiences can instantly recognise the film to be a comedy.
All of these factors help to set the tone and mood for the rest of the film.