Episodic or sustained anxiety without a disorder of mood (i.e., without depression) is classified as generalized anxiety disorder, as reviewed by Stein and Sareen, or formerly, anxiety neurosis. The more colorful term neurocirculatory asthenia (among many others) had been applied to the chronic form when accompanied by prominent fatigue and exercise intolerance, in which case it blends into the fatigue states discussed earlier. Some writings have emphasized that uncontrollable worry, as much or more than as nervousness, characterizes generalized anxiety disorder and that these patients describe a sense of helplessness in the face of their anxiety. This is contrasted to the experience of hopelessness that pervades depression.
The symptoms of anxiety may, however, be part of several other psychiatric disorders; it may be combined with other somatic symptoms in hysteria and is the most prominent feature of phobic disorder. Symptoms of persistent anxiety with insomnia, lassitude, and fatigue should always raise the suspicion of a depressive illness, especially when they begin in middle adult life or beyond. Also, unexplained anxiety or panic attacks may sometimes herald the onset of a schizophrenic illness. As with fatigue, the symptoms of both anxiety and depression are prominent features of the postconcussion syndrome, and of posttraumatic stress syndrome. These disorders highlight to us the difficulty in separating generalized anxiety disorder as a unique psychiatric entity. When visceral symptoms predominate or the psychic counterparts of fear and apprehension are absent, the presence of thyrotoxicosis, Cushing disease, pheochromocytoma, hypoglycemia, and menopausal symptoms should be considered.
This state has been alluded to previously in several contexts, but in the past decades it has come to have specific connotation and to stand as a separate disorder. The defining aspects are that an extremely stressful or traumatic event causes fear and helplessness, triggering a persistent psychologic state in which the patient reexperiences the event, avoids reminders of it, and is in a constant state of hyperarousal. Current diagnostic criteria require that this condition persist for over a month; if briefer, the condition is termed “acute stress disorder.”
Even proponents of posttraumatic stress disorder (PTSD) as a separate medical condition acknowledge that there is considerable overlap with anxious depression, the critical difference being the existence of a triggering traumatic event. They make the point that the original event may not be initially articulated by the patient but symptoms such as palpitations, dyspnea, dysphoria, and unexplained pains and other physical symptoms may be prominent, just as in depression. The biologic distinctions between anxious depression and PTSD include lower-than-normal cortisol levels, an attenuated increase of these levels in the immediate aftermath of the event, and an exaggerated suppression in response to dexamethasone. However, elevated circulating levels of norepinephrine and increased sensitivity of alpha2-adrenergic receptors that are found in the posttraumatic syndrome are shared with all other anxiety states (Southwick et al). Many of these studies have been poorly controlled.
It is apparent that there is a wide range of human vulnerability to persistent psychologic difficulties after traumatic events. In all probability, this parallels to some extent an endogenous susceptibility to PTSD. Examples of this are the elicitation of PTSD symptoms in susceptible persons by events not even witnessed personally, such as national disasters that are shared by large populations but produce symptoms in only a very few individuals.