5. Connected with these changes in the sensory excitability and with states of depression and exaltation, there are regularly simultaneous changes in the interconnection and course of psychical processes. Using the concept consciousness that we employ to express this interconnection (p. 203), we may call these changes abnormal changes of consciousness. So long as the abnormity is limited to the single psychical compounds, ideas, emotions, and volitions, consciousness is of course changed because of the changes in its components, but we do no speak of an abnormality of consciousness itself until not merely the single compounds, but their combinations also exhibit some noticeable abnormities.
These always arise, to be sure, when the elementary disturbances become greater, since the combination of elements to compounds and of compounds with one another are processes that pass continuously into each other.
Corresponding to the different kinds of combination that make up the interconnection of consciousness (p. 223), there may be distinguished in general three kinds of abnormities of consciousness:
1) changes in the associations, 2) changes in the apperceptive combinations, and 3) changes in the relation of the two forms of combination to each other.
6 . Changes in associations are the first to result directly from the elementary disturbances. The increase of sensory [p. 271] excitability changes normal assimilations into illusions of fancy, and this results in an essential disturbance in the associative processes of recognition (p. 237): sometimes that which is known appears to be unknown, and then again what is unknown appears familiar, according as the reproduced elements are connected with definite earlier ideas, or are derived from perceptions that have only a remote relation to one another.
Then, too, the increased sensory excitability tends to accelerate the association, so that the most superficial connections, occasioned by accidental impressions or by habit, are the ones that predominate. The states of depression and exaltation, on the other hand, determine mainly the quality and direction of the association.
In similar manner the elementary ideational and affective change influence apperceptive combinations, either retarding or accelerating them, or else determining their direction. Still, in these cases all marked abnormities in ideational or affective processes result in an increase, to a greater or less degree, of the difficulty of carrying out the processes connected with active attention, so that often only the simpler apperceptive combinations are possible, sometimes even only those which through practice have become simple associations. Connected with the last fact mentioned are the changes that take place in the relation between apperceptive and associative combinations. The influences discussed so far are in the main favorable to associations, but unfavorable to apperceptive combinations, and one of the most frequent symptoms of a far-reaching psychical abnormity is a great preponderance of associations. This is most obvious when the disturbance of consciousness is a continually increasing process, as it is in many cases of insanity. It is then observed that the functions of apperception upon which so-called imagination and understanding are based, are more and more supplanted [p. 272] by associations, until finally the latter are all that remains of the disturbance progresses still further, the associations gradually become more limited and confined to certain habitual combinations (fixed ideas). Finally this state gives place to one of complete mental paralysis.
7. Apart from mental diseases in the strict sense of the term the irregularities of consciousness just discussed are to be found in two conditions that appear in the course of normal life: in dreams and hypnosis.
The ideas of dreams come, at least to a great extent, from sensations, especially from those of the general sense, and are therefore mostly illusions of fancy, probably only, seldom pure memory-ideas that have become hallucinations. The decrease of apperceptive combinations in comparison with associations is also striking, and goes to explain the frequent modifications and exchanges of self-consciousness, the confusion of the judgment, etc. The characteristic of dreams that distinguishes them from other similar psychical states, is to be found, not so much in these. positive, as in their negative attributes. The increase of excitability which is attested by the hallucinations, is limited entirely to the sensory functions, while in ordinary sleep and dreams the external volitional activity is completely inhibited.
When the fanciful ideas of dreams are connected with corresponding volitional acts, we have the very infrequent phenomena of sleep-walking, which are related to certain forms of hypnosis.
Motor concomitants are generally limited to articulations, and appear as talking in dreams.