It is very common for some people to imagine something while they are in the process of falling asleep. This experience is calledhypnagogic hallucinations. These hallucinations may consist of visions, sounds or other sensory experiences that are quite vivid. They can be so realistic, disturbing and overwhelming that you may wonder if this is a true experience. Sometimes, people also experience similar hallucinations as they wake up from sleep, and these are called hypnopompic hallucinations.

What Are the Symptoms of Hypnagogic Hallucinations?

You may experience various hallucinations that are related to any of your senses. These may last a few seconds to a few minutes, and commonly include:

1. Visual Hallucinations

You may see geometric patterns, lines or static images, which may be in the form of people, objects or sceneries. In a fleeting hypnagogic state, you may try moving in closer to see details, but the scene suddenly disappears as you awaken.

2. Auditory Hallucinations

Auditory phenomenon such as sounds from everyday life may intrude in your dream. These may include the sound of a phone ringing, an airplane flying by or someone calling your name. These sounds are often imagined and may become part of your dream.

3. Tetris Effect

As you fall asleep, the most recent event of the day or the most memorable events are still whirling in your head. For example, if you were doing some repetitive task at work, it may be replaying in your mind as you fall asleep. This is the Tetris effect, which is named after the video game with the same name.

4. Sleep Paralysis

You experience sleep paralysis in all stages of sleep. Your body is frozen while you are dreaming. You wake up in terror, but are relieved to realize that you were just dreaming. Although your body is in paralysis during REM sleep, the paralysis may persist during the transition from sleep to waking state, or vice versa. This is often associated with intense emotional states, which can jolt you to suddenly wake up while your body is still coming out of sleep.

5. Other Symptoms

Other symptoms of hypnagogic sleep include smelling something which is not actually there, feeling spiders or insects crawling on your skin, experiencing jerks and other sensory experiences.

What Cause Hypnagogic Hallucinations?

Hypnagogic hallucinations can be caused by many reasons. The common causes of hypnagogic hallucinations include:

• Sleep deprivation and physical exhaustion, which can blur the line between wakefulness and sleep, are known to cause hallucinations in some individuals.
• Extreme or prolonged stress, which can impede your thought processes and produce hallucinations.
• Meditation or sensory deprivation, which prompts the brain to compensate by forming hallucinatory perceptions. This is common among deaf and blind individuals.
• Electrical/neurochemical brain activity, which may occur before a migraine or epileptic attack, can also cause hypnogogic hallucinations.
• Illegal drugs like LSD, ecstasy and mescaline are hallucinogens that can trigger these sensations. Other drugs that have hallucinatory effects include marijuana, PCP and some prescription medications.
• Brain damage/disease, which can cause changes in brain function and produce hypnagogic or hypnopompichallucinations.
• Mental illnesses, such as schizophrenia, are associated with auditory and visual hallucinations.

How Are Hypnagogic Hallucinations Treated?

1. Treat the Underlying Cause

Your doctor needs to rule out any sleep disorders or illnesses first. Your treatment will depend on what the doctor finds, and these may include medications for depression, anti-psychotic drugs for schizophrenia or lifestyle changes for sleep deprivation.

2. Adjust Your Lifestyle

Many sleep disorders improve with lifestyle modification. This includes getting enough sleep, avoiding illegal drugs, eating a healthy diet and drinking plenty of water. Managing stress levels is also important in improving sleep habits. If you are taking any medications, ask your doctor if they may cause your symptoms.

3. Accept Your Symptoms as a Normal Part of Daily Life

There is no specific treatment for these symptoms, especially if you have no underlying illness or disorder. You may just need to relax instead of worrying about these hypnogogic hallucinations.

4. Psychological/Psychosocial Treatment

This treatment may be helpful to teach you taking skills to deal with persistent hallucinations. Psychologist may also help you find out what causes your problem.