Here is how the DSM IV (Diagnostic & Statistical Manual of Mental Disorders) defines insomnia:

DSM-IV Diagnostic Criteria for Primary Insomnia

American Family Physician, April 1, 1999

A.The predominant complaint is difficulty initiating or maintaining sleep, or

nonrestorative sleep, for at least 1 month.

B.The sleep disturbance (or associated daytime fatigue) causes clinically

significant distress or impairment in social, occupational, or other important

areas of functioning.

C.The sleep disturbance does not occur exclusively during the course of

narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder,

or a parasomnia.

D.The disturbance does not occur exclusively during the course of another

mental

disorder (e.g., major depressive disorder, generalized anxiety disorder, a

delirium).

E.The disturbance is not due to the direct physiological effects of a substance

(e.g., a drug of abuse, a medication) or a general medical condition.

Reprinted with permission from the American Psychiatric Association. Diagnostic

and statistical manual of mental disorders. 4th ed. Washington, D.C.: American

Psychiatric Association, 1994:557. Copyright 1994.

COPYRIGHT 1999 American Academy of Family Physicians

COPYRIGHT 2008 Gale, Cengage Learning

So, no, I don't think insomnia means you can't sleep EVER; I think not sleeping at night counts. At least, my doctors told me it does. Hope this helps!