Hypnagogic hallucination is episodes of seeing and hearing things as one is falling asleep. These dreams can be frightening and can often cause a sudden jerk and arousal just before sleep onset. For example, you may see yourself falling and awaken with a sudden jerk, just before impact. The experiences are often frightening. Sleep deprivation, irregular sleep schedules, and medications all can predispose to occurrences of this phenomenon.
Hypnagogic hallucinations can occur at sleep onset, either during daytime sleep episodes or at night. They are usually quite vivid, and often involve vision. The visual hallucinations usually consist of simple forms – colored circles or parts of objects – that are constant or changing in size. People may also see the image of an animal or a person, and are more often in color. Auditory hallucinations are also common, but other senses are seldom involved. Hypnagogic hallucinations are dreams that intrude on wakefulness, which can cause visual, auditory, or touchable sensations. They occur between waking and sleeping, usually at the onset of sleep, and can also occur about 30 seconds after a cataleptic attack. Hypnagogic hallucinations are a feature of narcolepsy.
Sleep-related hallucinations are usually visual (seeing things), though they can be auditory (hearing things), tactile (sensation of feeling something) or kinetic (feeling of motion or movement). They more commonly occur with sleep onset but can happen with morning awakenings (hypnopompic hallucinations) as well. Sleep related hallucinations can be frightening and may, at times, be associated with other sleep behaviors such as sleep walking or sleep talking.
The underlying cause of sleep related hallucinations is not always clear. Factors known to bring these about or increase the frequency of occurrences include younger age, current drug use, past alcohol use, anxiety, mood disorders, insomnia and lack of sleep. Certain medications may also cause this as a side effect. In addition, these hallucinations may be a sign or symptom of another sleep disorder, such narcolepsy, a primary nightmare disorder or, rarely, they could be part of sleep-related seizures (epilepsy). Psychiatric disease should also be included as a possibility, though assuming these hallucinations occur only after sleep onset, then this would be much less likely. Depending on the underlying cause or factors associated with the hallucinations, the hallucinations may decrease or resolve with age.
Sleep paralysis is commonly seen in young adults and often associated with stress. In most cases, these episodes do not represent a primary sleep disorder and tend to resolve over time. However, when they occur in association with sleep-related hallucinations and excessive sleepiness, narcolepsy should be considered.
Consult your doctor for further information on Hypnagogic hallucinations.
Disclaimer: The following discussion is intended to provide general information. Only your physician can determine, diagnose, treat and know what is right for you.