Most of us feel unusually sleepy during office hours or even early in the evening once in a while. We blame it on lack of sleep the previous night, being physically exhausted, etc and really do not bother to find out the real excessive daytime sleepiness causes, thinking such a phase would soon be over; luckily enough, they do pass and we feel energetic all over again.

But at times such excessive sleepiness begin to dominate our lives; we feel sleepy most of the time…feel like taking short naps whenever or wherever and worst still, do not feel refreshed, no matter how many such naps we have taken.

Causes of excessive sleepiness should be probed further and if necessary, officially diagnosed and treated, as there are very high chances that you have been affected with a rare but serious sleep disorder called hypersomnia. Listed as a ‘rare disease’ by the Office of Rare Diseases (ORD) of the National Institute of Health (NIH), idiopathic hypersomnia, a sub-category of hypersomnia affects close to 200,000 people in the US.

Hypersomnia causes: is it just tiredness?

As strange as it may sound, though the symptoms are similar, excessive daytime tiredness related to hypersomnia causes and the kind of fatigue we feel after a late night or having been deprived of sleep the previous night have different origins.

When hypersomnia causes excessive sleepiness during the day, the symptoms are more extensive: you sleep for inordinately long hours; wake up very late; feel disoriented and confused on waking up; have low appetite; suffer from irritability, depression and hallucinations; you are incapable to think fast and your speech is slow.

What could be the causes of hypersomnia? There are plenty of factors that could cause excessive daytime sleepiness. Here are some causes of excessive sleepiness that you might find strange, but they are true all the same:

• The most common of all hypersomnia causes is sleep deprivation, which has a cumulative effect on the neurobehavioral functioning of the body.

Causes of hypersomnia are easier to understand if they are categorized according to their origin:

• Neurological origin or fallout of existing sleep disorder

-         Close to 10% of cases diagnosed with idiopathic (‘no known causes’) daytime hypersomnia are affected by narcolepsy.

-         Injuries or disorders caused by head trauma, accident involving the brain, encephalitis, brain tumor, restless leg syndrome, etc.

• Excessive daytime sleepiness causes related to lifestyle choices or mental disorders:

-         Depression

-         Inadequate sleep hygiene

-         Consumption of excessive amounts of alcohol (most common)

-         Jet lag, nightshift switchovers, etc, that disrupt the circadian rhythm.

• Causes of excessive sleeping related to disorders that could be co-existing:

-         sleep apnea

-         congestive heart failure

-         COPD

-         Coronary heart disease

-         Anemia

-         Hypothyroidism

-         Mononucleosis

• Causes of hypersomnia related to medications:

-         Clonidine

-         Beta blockers

-         Anticonvulsants

-         Anti-depressants

-         Medicines for Parkinson’s’ Disease

-         Anti-diarrheal medicines

-         barbiturates

-         Benzodiazepines

-         Medicines that treat nausea and vomiting (anti-emetics)

-         Anti-histamines

-         Anti-spasmodic medication

-         Skeletal muscle relaxants