Anxiety comes from a number of possible sources. It is most often thought of as a recognition by the mind (either consciously or unconsciously) of danger. If a task of the mind and body is keeping one safe, this makes perfect sense. Even a tiger in a cage might cause a sense of anxiety.
Freud actually felt anxiety had two different sources. Most people think only of his ‘second theory of anxiety’; anxiety is a signal of danger either conscious or unconscious. His, often overlooked, first theory of anxiety is that anxiety is the residual experience left over from repressed emotions. This is very interesting, let’s look a little further into this idea.
Anxiety as White Noise
In some situations, the defenses can repress or strip away all thought content and/or awareness of the emotions. Instead of recognizing what is going on, there is simply a sense of being stirred up. When this happens, one’s basic experience is not identifiable; the thought-content of the idea or fantasy has been repressed or otherwise stripped away by the defenses. Likewise, the characteristics of the emotions can be stripped away or repressed. This may be a foreign idea at first. However, think for a moment: have you had an experience where you were told you look angry/sad/stressed/upset in some way and prior to (or maybe even after) being told this, you have no experience of that emotion? In this case, although you may not be aware of your feelings, other people are picking up on something.
In other words, troublesome ideas, emotions or fantasies can have the thought content and/or emotional markers repressed or removed leaving a general sense of agitation – essentially a ‘white noise’ of being stirred up.
A developmentally normative stage for children is to have a sense of omnipotence. This is frequently cited in psychological literature or the literature on family studies when a younger child endures abuse, or perhaps a parental divorce. In these instances, it is not uncommon for a child to believe somehow, he or she is responsible. The child may tell herself, “If I was a better kid my parent would (would not) beat me/divorce/etc.”
This experience of omnipotence (whether conscious or unconscious) can lead a child to worry her thoughts, feelings and/or fantasies can be dangerous. It is easy to imagine a child could become very angry at a parent, have a passing thought of harm coming to the parent and then become extremely anxious and/or worried something terrible might happen. This may not be apparent to many people, but this is an experience which is familiar to parents, teachers and child therapists.
Anxiety: Coming from Repressed Emotions (or Thoughts)
Following from the scenario outlined above, we can understand how a child (or an adult) may work to defend against an awareness of difficult thoughts or feelings. The thought and/or feeling may be consciously experienced at first. However, the defenses can over time repress the thought, feeling or fantasy. What might be left over is the sense of agitation, perhaps a foreboding or danger. Later, the connection is forgotten or lost. Over time, all that may be in awareness are various manifestations of anxiety or agitation, such as physical agitation, moodiness, anxiety and sometimes even anxiety attacks or panic attacks. Because the defenses have hidden the connections or even emotions, the cause(s) of the anxiety seems to be a mystery.
More interesting information on anxiety can be found here