Cataplexy
Periods of muscular weakness triggered by strong emotions such as laughter, anger and surprise.

Circadian Rhythm
This is our own internal time-keeping clock and is related to the 24-hour light-dark cycle produced by the 24-hour rotation of the earth. Circadian rhythms control our sleep and wakening and is influenced by light. It adjusts to our environment’s daily light–dark cycle and, therefore, changes throughout the year. A regular waking time in the morning strengthens the circadian rhythm and can help with sleep onset at night.

Circadian Rhythm Disorders
These occur when our normal sleep-wake pattern is out of ‘synch’ with the light-dark cycle. They can be short-term or transient such as resulting from jet lag or shift work or persistent where people experience problems with their phases of sleep or have irregular sleep-wake patterns.

Chronic
A medical condition, such as insomnia, that lasts a long time.

Clinical Trials
All new medicines available on prescription will have been the subject of many clinical trials by researchers to ensure the safety, quality and efficacy of the treatment.

Hormone
‘Chemical messengers’ produced by the body which have a special function.

Hypnogram
A diagram that summarises these five stages of sleep.

Hypersomnia
An excessive need to sleep.

Insomnia
A recognised sleep disorder in which people experience poor quality sleep for more than one month. There are two types: primary and secondary insomnia. The following symptoms are often present:
• not being able to get off to sleep
• nodding off during the day
• waking up too early
• not feeling refreshed after a night’s sleep and having difficulty functioning during the next day.

Irregular Sleep-Wake Pattern
These include sleep cycles that do not conform to a circadian rhythm.

Jet Lag
Travelling ‘long haul’ through different time zones of the world can upset our internal body clock (circadian rhythm) and contribute to primary, short-term insomnia. People affected feel ‘out of sorts’ and out of synch.

Melatonin
The main hormone produced in the brain to regulate the sleep-wake cycle. Melatonin plays an important role in setting your circadian rhythm to your environment. It’s production is affected by light; rising levels of melatonin as night falls tell your body it’s dark and time to sleep. Melatonin levels decline with age and some illnesses; people with Alzheimer’s or Parkinson’s diseases and arthritis also have reduced melatonin levels. Reduced melatonin levels may cause insomnia.

NREM (Non-Rapid Eye Movement)
Sleep Stages 1-4 of the sleep cycle comprising light sleep at stages 1 and 2, moving to deep sleep for cycles 3 and 4.

Narcolepsy
A disorder of sleep associated with excessive daytime sleepiness, involuntary daytime sleep episodes,
Interrupted sleep at night or cataplexy.

Night Terrors
This is linked to nightmares with children are often affected with this sleep disorder.

OTC
Over-the-Counter medicines are products which are licensed and can be bought only from a pharmacy or pharmacist with the need for a prescription. They have undergone rigorous tests to ensure their safety and efficacy. OTC medications for sleep may interact with other medicines you may be taken so do ensure that you discuss this first with the pharmacist.

Parasomnia
Difficulty waking up from sleep (for example, resulting from sleep walking).

Primary insomnia
Insomnia not caused by a physical or mental illness, the side effects of any medicine, alcohol, or illegal ‘street’ drug.

REM (Rapid-Eye-Movement)
Sleep Stage 5 and the final stage of sleep during which we dream, which may or may not be remembered once we wake up.

Restless Leg Syndrome (RLS)
This disorder creates unpleasant feelings or pain in the legs causing a strong desire to frequently move your legs.

Secondary
Insomnia which is caused by physical or mental ill health, pain (such as from arthritis), the side effect of a medicine physical or mental illness, the side effects of any medicine. Being depressed or anxious can also lead to secondary insomnia.

Sedative
Drugs which slow down or depress the normal body functions. Sleeping tablets or antidepressant medications may have a sedative effect on the body.

Short-term insomnia
This is often related to external stresses, such as preparing to sit a test and can be relieved by removal of the stress.

Sleep Apnoea
A sleep disorder in which breathing is temporarily stopped or interrupted whilst asleep.

Sleep Architecture
The ‘building blocks’ of sleep and identifies our normal sleep patterns. A normal sleep cycle comprises five different stages and during the night, you will need to go through the sleep cycle several times in order to benefit from get the refreshing, restorative quality of sleep.

Sleep Diary
A diary for you to complete to help record the quality of your sleep over a period of time.

Sleep Drunkenness
A sleep disorder in which people wake up in a confused state. This often happens if you attempt to wake someone from a deep sleep.

Sleep Hygiene
Good sleeping habits. If you are having difficulty sleeping, there are a number of tips you can try to help you achieve good quality sleep. For example, making sure your bedroom is quiet, your bed comfortable and not having a meal too soon before going to bed.

Sleepwalking
People affected get up out of bed and walk about as though awake, even though they are in a state of sleep.