Sleep deprivation

Sleep deprivation is a general lack of the necessary amount of sleep. This may occur as a result of sleep disorders, active choice or deliberate inducement such as in interrogation or for torture

Physiological effects Generally, lack of sleep may result in:

aching muscles
blurred vision
clinical depression
colorblindness
daytime drowsiness and naps, excessive daytime sleepiness (EDS)
decreased mental activity and concentration
depersonalization/derealization
weakened immune system
dizziness
dark circles under the eyes
fainting
general confusion
hallucinations (visual and auditory)
hand tremors
headache
hyperactivity
hypertension
impatience
irritability
lucid dreaming (once sleep resumes)
memory lapses or loss
nausea
nystagmus (rapid involuntary rhythmic eye movement)
psychosis-like symptoms
pallor
slowed reaction time
slurred and/or nonsensical speech
weight loss or gain
severe yawning
increased desire for sexual activity
delerium
symptoms similar to:
Attention-deficit Hyperactivity Disorder
alcoholic intoxication

Diabetes

A 1996 study by the University of Chicago Medical Center showed that sleep deprivation severely affects the human body's ability to metabolize glucose, which can lead to early-stage Diabetes Type 2.