Anomalies in the flexibility of associations

Over-flexibility is evinced in the rapid flitting from one subject to another which is typical of the grass-hopper mind. Associations are too loose so that there is a low level of distraction and the train of thought is lost. Circumstantiality is the following up of associated ideas although the original train of thought is not lost and eventually is reverted to. The extreme form of over-loose associations is mania and, to a lesser extent, hypomania. There is a rapid play on words, with punning and rhyming but no coherence.

The reverse case is manifest in preoccupation. Associations are available but their range is limited. There is furious thought around one theme, often an unsolved problem. Included in this area is brooding, a preoccupation with a subject with high negative affective capacity. Preoccupation is common at some time with everyone, but others are prone to preoccupation and are said to have a one-track mind. Rather than an over-fluidity of associations, here there is a lack of associations or an over-fixity of focus. In severe mental disorders this may reach an extreme beyond normality, when it is referred to as perseverance.