In what follows I will argue that the Psychosis (or the psychotic phenomena) which characterise enhanced Creativity are distinct in form, from the Psychosis of most Psychotic illnesses. Also that severe psychosis of any kind is always un-creative in itself - a barrier or block to purposive creative activity.
By Psychosis I mean psychotic illnesses; that is, illnesses marked by psychotic phenomena.
Psychotic phenomena are primarily
1. Hallucinations - usually hearing voices (when nobody is there) and seeing things (which aren't there). The creative state of mind is akin to (or actually) day-dreaming or lucid dreaming.
2. Delusions - false belief - usually almost unshakeable, and which dominate behaviour. Most often these are 'paranoid' - which means delusions of self-reference: i.e. that 'everything' in the environment refers to the deluded person in some way. One common type of paranoid delusion is delusions of persecution - that there is some kind of 'conspiracy' to 'get' the deluded person.
3. Thought disorder - this refers to an inferred abnormality in the form of thought, abnormality in the 'stream of consciousness' - this being inferred partly from the speech and behaviour of the subject as observed, and partly from self-reports of the subject either at the time of interview (describing their won thoughts) or else retrospective after some degree of recovery.
Thought disorder ranged from acceleration or slowing of though (in mania or depression respectively), and includes what feels like the interruption or stopping or loss of thought, or that thoughts are being read or experienced by others, or being put into the mind from externally. These are taken to be attempted descriptions of strange and puzzling experiences.
4. Catatonia - which refers to a very wide range of purposeless, un-understandable movement disorders associated with psychotic illnesses - including freezing, posturing, strange mannerisms, and undirected excitement.
These Psychotic phenomena can occur in the 'functional' psychoses of schizophrenia, mania, psychotic melancholia/ depression, and brief undifferentiated psychoses; brain diseases and disorders such as delirium/ acute organic states and dementia (especially the Lewy body dementia of Parkinsonism), and are caused by drugs and drug withdrawal (these are actually types of delirium), and sometimes in epilepsy or following brain injury.
There is a fairly clear distinction between the Psychotic phenomena which constitute creative states and those which occur in most Psychotic illnesses. This can conveniently be summarized by thinking of the typical shaman experience as listed in anthropological studies.
SHAMANIC/ CREATIVE PSYCHOSIS
The key to potentially-creative Psychotic phenomena is that purposive thought is retained, the links between topic are retained, and memory is retained.
1. Visions and visual hallucinations: these may be symbolic pictures of the working-out of problems, or coded answers to long-pondered problems. Creative hallucinations seem usually to be visions; although sometimes they are voices that advise, instruct, warn (e.g. Socrates's 'daemon' that apparently spoke to him).
2. 'Delusions' or strong and dominating beliefs that would be regarded as dubious or false by most people; which take the form of strong convictions coming-upon the subject asif from outside (or arising from within him) in non-logical ways.
3. The subject would have a strong awareness of his inner monologue, the 'stream of consciousness', perhaps hearing his thoughts spoken aloud; perhaps combined with an expanded associations of ideas, linking subjects in surprising ways (so that one idea reminds the subject of many others, beyond what is usual); perhaps combined with a more rapid, accelerated 'flight of ideas' - when the stream of thought seems sped-up to a rapidity beyond normal - and which when spoken aloud other people may find it difficult to follow. In sum, the speech may be rapid, bounce between subjects on the basis of wide-ranging hard-to-follow (but real) associations.
PSYCHOTIC DISEASE/ NON-CREATIVE
The nature of Psychotic phenomena can be such as to impair or utterly prevent creativity. The uncreative state of mind is like most people's experience and memories of most dreams during sleep - i.e. an uncontrolled, passive experience; lacking purpose and direction; often interrupted, jumping 'randomly' between subjects, evoking an emotion of perplexity/ puzzlement, without any direction or apparent meaning, and very swiftly forgotten on waking.
1. There may be poor concentration, poor memory. excessive distraction, and being overwhelmed by strong emotions (whether misery, euphoria, perplexity or fear) so the person simply exists in the present moment.
2. Thought disorder may be so severe as to disconnect one idea from another and prevent purposive and directed thought. Subjective thoughts may be slowed to a near standstill (in Psychotic depression), or so fast as to be a blur (in mania); thoughts may be frequently interrupted, or stopped, or lost (in schizophrenia) - so the subject changes abruptly without any known link, or suddenly all thoughts leave the head with no memory for what went before. Delerium and Dementia are both associated with extremely poor ability to sustain a strain of thought.
3. Hallucinations are most typically auditory - hearing voices. These voices may be so intrusive (loud, multiple voices, aggressive or insulting voices) as to compel almost all the subject's attention, and prevent directed thinking and problem solving.
4. Catatonia is a physical manifestation of Psychotic disease - and (in its many forms) generally seems to interfere severely with, or utterly prevent, purposive thought or any form of creative action.
Note: Psychosis is an extreme of normal states, on a continuum
In practice, and despite some traditional formulations, Psychotic phenomena are not qualitatively distinct categories from normal, but rather on a continuum with normal.
So Hallucinations are defined as sensory perceptions with no object - but hallucinations merge into misinterpretations of real perceptual stimuli and illusional misinterpretations of real perceptions (e.g. a coat hung on a chair is seen as a looming and hostile person, the sound of a murmur of indistinct conversation is experiences as clear persecutory voices).
Auditory hallucination may sometimes be induced by exposure to unstructured sound or nonsense words; or 'drowned out' with loud music or speech from a high volume TV or iPod, or alleviated by cognitive therapy methods - demonstrating that hallucinations are NOT autonomous of the environment.
And out-and-out delusions merge into overvalued or eccentric ideas and obsessive concerns.
And 'flight of ideas' can range in severity from rapid, allusive, witty and 'brilliant' conversation; to incomprehensible nonsense, random 'word salad' and pretentious, imprecise, inconclusive ramblings on 'philosophical' themes.
The missing link may be strong emotional states amplifying a tendency to misinterpret evidence; so that a jealous man with low self-esteem who mistrusts his wife may develop delusional jealousy by a biased interpretation of ambiguous evidence; or a very frightened schizophrenic may interpret ambiguous environmental perceptions as conclusive evidence of a hostile conspiracy.
NOTE: As a general point, it is important to regard high Psychoticism Creativity as being an adaptive phenomenon - 'designed' (by natural selection) for the purpose of being creative (innovating in ways beneficial to the group, solving difficult problems afflicting the group etc.).
Therefore, the creative way of thinking, i.e. the 'flight of ideas', wide associations, awareness of the stream of consciousness, tendency to have visions and to get non-logically-derived ideas are NOT examples of mild pathology - but ARE hard-wired systems for creativity.
This is emphasized by the way in which the creative way of thinking is linked to the creative persons ability, interests and motivations.
Thus creativity is a coordinated package: an adaptive package.
(And creativity is NOT - except perhaps very unusually - a rare and accidental combination of pathologies which just happen to yield beneficial results.)