Neurosis is a broad term covering many forms of psychological distress. A neurosis is not as sever as a psychoses, which involves a psychological break from external reality. Anxiety neurosis is a condition characterized by diffuse anxiety and often somatic manifestations of fear. Anxiety is a normal and appropriate response to stress but becomes a recognizable illness when it is disproportionate to the severity of the stress, continues after the stressor has gone, or occurs in the absence of any external stressful event. Neuroses with anxiety as the chief symptom are common: around 16% of the population are affected by some form of an anxiety illness at any one time.