A study from Hong Kong Shue Yan University shows that people who sleep face down are more likely to have dreams about being tied up, smothered, and other nightmarish themes. Note that this may also increase the likelihood of erotic or sexual dreams, so you may not receive the desired effect. If you cannot get to sleep on your stomach, the next most "nightmarish" sleeping position may be lying on your back, followed by lying on your left side. While eating spicy, salty, or fatty foods are commonly believed to cause nightmares, scientists are divided over the exact effect of these substances. Some argue that the disruption of your sleep cycle may even slow down the onset of dreaming, potentially resulting in fewer dreams or nightmares. Others think they may increase dream intensity, at least in some people, and suggest that each person pay attention to his own body's response. Try watching a horror movie, playing a scary video game, or reading ghost stories before bed. If you have a specific fear or anxiety, look at images of it or simply lie in bed imagining a "nightmare scenario." Aim to make yourself only slightly scared or anxious. If you are terrified out of your wits, you are unlikely to fall asleep in the first place. While the effect of vitamin B6 on dreams is not thoroughly studied, many people swear by its ability to increase the vividness of dreams. One study suggests that it may be effective, either due to an effect on the dreaming process itself, or an enhancement of your ability to remember dreams. Including vitamin B6 from both food and supplements, daily intake should not exceed 60 mg for children 9–13 years old; 80 mg for teenagers 14–18 years old; or 100 mg for adults 19 years or older. Some people report having more vivid or bizarre dreams when taking melatonin, which may give you a new dream experience even if they are not outright nightmares. At least one study supports this idea, suggesting that dreams involving transformations are especially likely to occur under melatonin. Melatonin is typically taken in doses of 1–20mg, and rarely causes health problems. However, due to interactions with other medications, possible negative effects during pregnancy, and the chance of an allergic reaction, you may wish to consult a doctor before taking melatonin. Caffeine, alcohol, and nicotine can all disrupt your sleep cycle. This can potentially cause nightmares if taken in small quantities. However, ingesting any of these substances in too large a quantity can disrupt your sleep too much. Reduce your intake of these substances if you have difficulty falling asleep in the first place, if you wake up repeatedly in the night, or if you feel tired after waking up. These are all signs that you may be getting less restful sleep, which may reduce the amount you dream. If you rarely or never consume these substances, the effect is likely to be more potent than you expect. It is not recommended that you begin taking these drugs solely to induce nightmares.
Sleep face down. Try eating certain foods before bed. Scare yourself slightly before going to bed. Consider taking vitamin B6. Try taking melatonin. Take certain substances in moderation.