Volcanologists classify eruptions into several different types. Some are named for particular volcanoes where the type of eruption is common; others concern the resulting shape of the eruptive products or the place where the eruptions occur. Here are some of the most common types of eruptions:
The study of anxiety is at the root of psychoanalytic explorations of the human condition. Anxiety is a warning signal that danger is present and that overwhelming emotions may be felt, giving rise to unmanageable helplessness. The danger may be perceived as arising from internal or external sources, and be the response to a variety of powerful phantasies in the unconscious mind.
When the intensity, duration, and/or frequency of anxiety become distressful and chronic, such that it interferes with a person's functioning, it is often referred to as pathological anxiety. Anxiety disorders represent variant forms of this pathological anxiety. Therefore, the difference between normal anxiety and abnormal anxiety is this: anxiety is considered normal and adaptive when it serves to improve peoples' functioning or wellbeing. In contrast, abnormal anxiety is a chronic condition that impairs peoples' functioning and interferes with their well-being.