Here are the diagnostic criteria for Generalized Anxiety Disorder according to the Diagnostic And Statistical Manual of the American Psychiatric Association. 

A. Excessive anxiety and worry (apprehensive expectation), occurring more days than not for at least 6 months, about a number of events or activities (such as work or school performance). 

B. The person finds it difficult to control the worry. 

C. The anxiety and worry are associated with three (or more) of the following six symptoms (with at least some symptoms present for more days than not for the past 6 months). 

(1) restlessness or feeling keyed up or on edge 
(2) being easily fatigued 
(3) difficulty concentrating or mind going blank 
(4) irritability
(5) muscle tension 
(6) sleep disturbance (difficulty falling or staying asleep, or restless unsatisfying sleep)