Although some of the mental health issues the boys exhibit on the island can be attributed to their immaturity and are typical boy behavior, some easily fall into the category of a "mental health crisis." Bullying, teasing, and jealous competition—although unpleasant—are within the realm of normal behavior for boys twelve and under. But some or all of the boys also show signs of Post-Traumatic Stress Disorder, anxiety/paranoia, depression, narcissism, hallucination, extreme mob mentality, and sociopathic behavior.
At the beginning of the book especially, the littluns cry during the night and have nightmares. Even the older boys admit to sleeping poorly and having bad dreams. These sleep disturbances are typical of PTSD, and no wonder. The boys have suffered a severe trauma by being evacuated from London during a war, crash landing, and finding themselves without adult supervision on a strange island.
Ralph holds a meeting to discuss the anxiety and paranoia many boys suffer from. They have the feeling something is watching them from the forest. They imagine a "beast" that might live on the island or might come up from the sea. Ralph believes that talking about their fears will help, but Jack uses the boys' fears to attempt to gain leadership and prestige for himself.
Ralph is the character who seems to most clearly exhibit depression. When he is depressed, he finds it hard to use his reasoning abilities. Because he has been elected chief, even though he had no particular desire for that office, he places a lot of pressure on himself to improve life on the island and keep the boys acting in a civilized way. When his efforts fail, he blames himself and feels as if there is no use. When Jack leads the boys onto the beach during the evening meeting, Ralph refuses to call them back and suggests he should resign as chief. Later he has memory lapses and feels a "curtain" descending in his brain, all signs of depression.
Jack is the narcissist. He becomes angry whenever he can't be the leader. When he gets his chance, he sets himself up "like an idol" at his feast. His narcissism leads him to torture other boys and eventually to try to murder Ralph in a hunt.
An extreme mob mentality takes over the night of Jack's feast when the boys murder Simon and at the end of the book when they hunt Ralph. The feeling of anonymity in the crowd produces a decline in taking personal responsibility, which allows the boys to do things they would not normally let themselves do.
The boy who experiences an auditory hallucination is Simon, who hears a voice during what is probably the prodrome of an epileptic seizure.
Roger is the boy whose bullying descends to true sociopathic behavior when he rolls the boulder on Piggy and kills him.
Not surprisingly, given the trauma the boys experience, there are numerous mental health crises that take place in Lord of the Flies.
One aspect of Lord of the Flies is that while the boys experience extreme physical deprivation in the form of dehydration and starvation, they also experience all of the mental and emotional strain that comes from being stranded on an uninhabited island. This experience would be hard enough for an adult, but for a child, being away from the protection of the adult world, is even more of a strain; with this thought in mind, the reader can easily comprehend why several of the boys seem to experience a mental breakdown.
Simon, for example, already comes to the island with some sort of debilitating illness that causes fainting 'spells; his condition worsens under the oppressive heat of the jungle, and in chapter eight, "Gift for the Darkness," the reader sees Simon have a hallucination in which he converses with a pig's head, blacks out, and wakes up with a nosebleed in the next chapter. This episode would definitely be classified as a mental health crisis.
Ralph, too, experiences 'mental crises' in the form of regression and memory lapses. In chapter seven, Ralph notices that he has started biting his nails again, "though he could not remember wehn he restarted this habit not any time when he indulged in it" (109). Ralph's nail chewing signifies regression to earlier habits--comfort habits--from when he was a smaller child. Ralph remarks upon noticing the nails that he will "be sucking [his] thumb next" (109). He turns to these habits to diffuse the enormous amount of stress he feels, but then cannot remember when he actually chewed on his nails. Golding includes other details to suggest Ralph's memory loss in conversations with other boys, like when in Chapter Eleven, when the boys prepare to visit Castle Rock. Ralph can hardly remember about keeping the signal fire lit. When the other boys concernedly look at Ralph, he protests:
"'I hadn't,' said Ralph loudly. "I knew it all the time. I hadn't forgotten.'
Piggy nodded propitiatingly.
'You're chief, Ralph. You remember everything'" (173).
Although the other boys assure Ralph that he remembered, it is evident that they recognize that Ralph's memory and control is slipping away. The narrator observes that "the twins were examining Ralph curiously, as though they were seeing him for the first time" (173). Clearly the emotional and physical strain of the island has impacted Ralph's mental health, resulting in memory loss and mental fatigue.