If April is about daffodils and July is about watermelon, then October is about fear.

And for some reason, we can't get enough.

People want to be frightened, will pay to be frightened and will wait in line to be frightened, a fact not lost on the Alexandria Jaycees, who make $15,000 annually on their Haunted House with 13 rooms of terror, or the amusement park industry, which increasingly is adding Halloween horror to attractions.

Take the new "Brutal Planet" exhibit at Six Flags America in Prince George's County. Adults pay $5 at Brutal Planet--in addition to the regular $32 admission--to be welcomed in by faux police tape, a decapitated man and a chilling collection of corpse-like rock stars.

During the next 10 minutes, Satan leaps out from a wall, an all-too-real man screams as he is executed in an electric chair, human forearms are seared on a grill and disturbed, angry people quietly surround their visitors, staring, leering, spooking.

More? Okay. There's a guy vomiting, a woman--a real one--sitting on the toilet who screams as guests enter. Spiders, bats, monsters and aliens inhabit the dark corridors.

And people love it.

One recent evening, Dakesha Carson, 14, emerged crying and trembling, unable to compose herself enough to speak. Later, she reflected on why she would recommend the experience.

"For a challenge. To get the thrill," said the Clinton high school freshman.

Experts, and others who recently have been frightened silly, agree with Carson. Fear offers an adrenaline rush, a feeling of bravery.

"When you're afraid and you kind of confront the fear and it's not so fearsome, that's exhilarating," said Frank Farley, a psychology professor at Temple University who is a consultant to Busch Gardens on the topic. "You feel elevated and stronger because you've done it. Halloween is a social structure that allows us to do that."

A Six Flags spokesman declined to give numbers but said the new attraction is wildly popular. Williamsburg's Busch Gardens, which launched its "Howl-O Scream" exhibit this year, has seen a 20 percent increase in its October attendance, which it attributes to the new attractions, including "Transylvania Express," a haunted locomotive, and "The Dark Tower," a medieval castle.

Half of the roughly 7,000 attractions in the country are less than six years old, and attendance is growing about 30 percent a year, according to Haunted Attraction Magazine, itself a new venture.

"We're seeing increasingly that amusement parks are making use of the Halloween season," said Joel Cliff, spokesman for the Alexandria-based International Association of Amusement Parks and Attractions.

Ed Edmunds, the creator of Brutal Planet and owner of Colorado-based Distortions Unlimited, speculated that in our hyperkinetic, overstimulated world, it takes a hefty dose of adrenaline for people to feel the kick. Terror can be a very effective way to stimulate the rush.

"You would have to say it's not a good feeling to be terrified, but if you know you're in a safe environment, there's an exhilaration that you just can't beat," he said. "A roller coaster is the experience you would have in a car crash. It's just safe."

Edmunds also knows precisely where to draw the line. He toyed with it while designing Brutal Planet.

"We were going to have real paramedics go in and come out with this guy that's totally mangled, this unbelievable bloody mess," he said. "The problem is that's so realistic, they're no longer in fantasyland. People leave the line. Because you've violated that feeling of safety."

Television's former "Dr. Evil," Philip Morris, now owns Morris Costumes in North Carolina, which he says is the world's largest manufacturer and distributor to the haunted house industry. This is a guy who's thought about fear. Maybe too much.

"The important thing is to find the things that people have a natural fear of," he said. "Like a guillotine that doesn't cut off a head--that's not scary. A guillotine that cuts off the guy's head--that's okay. But what is really scary is if that head flies out of the basket and flies up toward you with blood spitting out of it. That's the unexpected."

Anticipation can also enhance fear, give it more punch. Jenny Allen, 14, who was recently lined up at a Fairfax movie theater to see "The Blair Witch Project," certainly thought so.

"If you know you're going to a scary movie, it's scarier," she said. "Waiting for something makes it even more scary."

Not everyone enjoys the sensation, said Sally Winston, co-director of the Anxiety and Stress Disorders Institute of Maryland in Baltimore. Some people have anxiety sensitivity, she said. They experience the adrenaline surge and instead of feeling aroused and excited by it, they sense only the body's "emergency danger response" coming on. They are "afraid of their own adrenaline surges," Winston said.

Some of the thousands of people who attend the Arlington Jaycees' haunted house every year doubtless fall into that category, said chapter president Ariel Jones. Many who visit the "Psycho" room, with "Mother" coming out of the shower, or Dante's kitchen, with brain appetizers and "finger food," don't really want to be there.

"Some people feel like they have to," Jones said. "It's a weird, weird concept. They're scared if they don't go, something's going to happen to them. We had someone come in a couple weeks ago who said, 'I have to do it. You have to do it on Halloween.' "

The feeling of compulsion can lead people astray. Take Will Calhoun, 10, a normally collected fifth-grader from the District. After he exited "Brutal Planet" last weekend, Calhoun was relieved to find a reporter waiting so that he could get his message out.

"They say, 'Not recommended for people under 12,' " Calhoun said breathlessly. "They have to say people like that cannot go through. People can sue you for that."

A few days later, Calhoun maintained his warning but insisted that the event had nonetheless been "fun."

"It gave you that kind of really scary but fun kind of feeling," he said.

CAPTION: Friends shriek as they tour the haunted house at Six Flags Great Adventure, which uses live actors to augment the horrors it provides each guest.

CAPTION: An actor in a "painting" will surprise visitors.

CAPTION: A spook hides, camouflaged against a wall.