Final answer:
Generalized Anxiety Disorder (GAD) is an anxiety disorder marked by persistent and excessive worry that lasts for at least 6 months, affecting daily life and including physical symptoms.
Step-by-step explanation:
The anxiety disorder that is marked by persistent anxiety for at least 6 months and in which the individual is unable to specify the reasons for this state is Generalized Anxiety Disorder (GAD).
GAD involves excessive, uncontrollable worry about everyday things. This worry is disproportionate to the actual significance of the events or circumstances. Individuals with GAD may worry about health, money, family, or work, despite there being no signs of trouble. The key difference distinguishing GAD from normal feelings of apprehension is the severity, longevity, and the fact that these worries interfere with daily life and are accompanied by physical symptoms such as fatigue, muscle tension, restlessness, and trouble sleeping.
It's important to note that while anxiety is a natural response to stress, anxiety disorders, such as GAD, are more severe. They persist over time and often require treatment, which can consist of psychotherapy, medication, or a combination of both. GAD is just one of many anxiety disorders, which also include conditions like panic disorders, social anxiety disorder, phobias, and post-traumatic stress disorder (PTSD).