Time Perception in Schizophrenia
Helena Hollis
MSc Mind, Language, and Embodied Cognition
An integrative model of time perception
“As we present time to ourselves, it simply does not agree with fact. To call time
subjective is just a euphemism... An entity corresponding in all essentials to the idea of
time... In relativity theory exists only in our imagination.” (Kurt Gödel , in Yourgrau 1999)
What is Schizophrenia?
“Schizophrenia names a persistent, often chronic and usually serious mental disorder affecting a
variety of aspects of behaviour, thinking, and emotion. Patients with delusions or hallucinations
may be described as psychotic. Thinking may be disconnected and illogical.
Peculiar behaviours may be associated with social withdrawal and disinterest.”
DSM IV
Schizophrenia is not a simple disorder, it is composed of various symptoms usually divided into positive (an
excess of function) and negative (a deficiency of function) (Bleuler, 1950), and any individual patient may
have a different balance and different strength of exhibited symptoms.
Symptoms include:
•positive-symptom dimension: psychosis - hallucinations and delusions
•negative-symptom dimension: changes in drive and volition - lack of motivation, social withdrawal, reduction in
spontaneous speech
•cognitive-symptom dimension: alterations in neurocognition - difficulties in memory, attention and executive
functioning
•affective dimension: affective dysregulation giving rise to depressive and manic (bipolar) symptoms
(van Os & Kapur, 2009)
According to Gödel there is no such thing as time out there in the world, and yet we clearly have temporal
experiences. However, there is also no such thing as a sense organ for time, rather our experience of time
comes from a combination of sensory information.
Our experience of time is a construct, and it is “shaped by anatomical and dynamical constraints of the
nervous system” (Van Wassenhove, 2009)
Van Wassenhove also points out that there is no absolute time ability, as there is absolute pitch. Time
perception is truly individual. However, it clearly does map onto the environment – through the senses which
build it up. So it is possible to have a distorted time perception, beyond individual differences.
Baars (1988) proposed a „global workspace‟, which combines long-range neural projections rather than
distinct, modular processing. Therefore even though different sensory modalities are processed at different
speeds (audition is processed faster, and seems more precise temporally than vision), there will be some
duration at which information enters the global workspace, and consciousness.
“One perceives time by reading out the brain‟s dynamics.” (Van Wassenhove, 2009)
This makes it extremely difficult to formulate one hypothesis that could cover schizophrenia in it’s entirety.
The role of memory
Deficits in time perception in Schizophrenic patients
A broader time perception clearly requires memory. Fuster divides this into three functions,
all mediated by the PFC:
Working Memory – for the past
Inference Control – for the present
Preparatory act – for the future
So the present is for us always extended into all three times.
Together this provides the kind of integrated, flowing sense of time we experience.
Deficits in time perception have been observed in a range of disorders,
and there is typically a trend to misjudge durations:
Working memory
This is the cognitive workspace, which contains all that can be kept in mind at a given time.
•Manic patients tend to overestimate duration
•Depressive patients tend to underestimate duration
However, schizophrenic patients show poor estimation without a trend. Results are not systematic (Vogeley and
Kupke, 2007)
Schizophrenic patients were asked to answer two kinds of discrimination questions:
•Do two stimuli have the same duration?
•Are they short or long?
They performed worse than controls but without a systematic bias towards over or underestimating. (Elvevag,
2003)
Dopamine transmission plays a large role in schizophrenia. Goldsmith et al (1997) found an increased number of
dopamine receptors in post mortem and PET scan studies of schizophrenics.
Interestingly, increase in dopaminergic transmission increases the speed of one’s ‘internal clock’, whilst
inhibition slows it down. (Rammsayer, 1993)
As schizophrenia is characterised by a disruption of communication in the brain, the unsystematic nature of
impairment is not surprising. It demonstrates that in healthy individuals, integration across the brain is key for
temporal perception.
“Working memory is essential for our subjective time experience by
providing an online access to actual perceptions and contextual memory
contents in the present.” (Vogeley and Kupke, 2007)
This is impaired in schizophrenic subjects, so it unsurprising that they struggle
with temporal tasks, as without reference to the past and an ability to compare it to the present,
temporal discrimination will be impossible.
Confabulation
“falsification of memory occurring with clear consciousness
in association with an organically derived amnesia” (Berlyne, 1972)
Can be similar to schizophrenic false beliefs.
Schnider and colleagues to posit a theory of confabulation as a disorder in temporal ordering of memories.
This can be described as a loss of “personal temporality” (Dalla Barba, Cappelletti, Signorini, & Denes,
1997), and so reflect a more general impairment of time awareness.
A related view is that confabulation arises out of confusion in the sources of memories. This incorporates
temporality, as when a memory comes from is one type of source. (Johnson, O'Connor, & Cantor, 1997)
Connectivity and Communication in the Brain
The brain exhibits ‘small world network’ properties (Liu, et al., 2008)
“Small-world networks offer a structural substrate for functional segregation and
integration of the Brain... and facilitate rapid adaptive reconfiguration of neuronal
assemblies in support of changing cognitive states” (Liu, et al., 2008)
So confabulation also appears to arise from a breakdown of communication, as information about the source
– particularly the temporal location - of a memory is not being combined with the memory itself.
Confabulation is a distinct disorder from schizophrenia, but as it does involve similar false beliefs a similar
failure of integration of information may underlie both.
Comparing healthy and schizophrenic subjects, Liu et al (2008) found that the schizophrenic group had
broadly disrupted connectivity. They concluded that “schizophrenia is a disorder of dysfunctional
integration among large, distant brain regions” (Liu, et al., 2008).
Bassett et al (2008) also describe schizophrenia as a ‘dysconnectivity syndrome’,
Furthermore, Rubinov et al.(2009) describe the abnormal connectivity in schizophrenia as a “subtle
randomisation” in the links in the network, due to which the perceptual whole breaks down.
As we perceive time though the integration of multimodal sensory information, this breakdown of
connectivity in schizophrenia is likely to be responsible for the disturbed time perception in schizophrenic
patients.
Re-defining Schizophrenia
Eugene Bleuler took the term “schizophrenia” from the Greek words 'schizo' (split) and
'phrene' (mind) (Bleuler, 1950)
In 2002, the Japanese Society of Psychiatry and Neurology replaced the old term for
Schizophrenia, "Seishin Bunretsu Byo" ("mind-split-disease"), with "Togo Shitcho Sho"
("integration-dysregulation disorder"). This appears to be a name which reflects the
nature of the disorder far closer.
Cognitive Dysmetria is a disturbance of coordination in motor and mental activity.
Vogele and Kupke (2007) posit this as the core deficit in schizophrenia:
“Schizophrenia... is interpreted as a structural disturbance of time
consciousness.”
References
Conclusions
Time awareness has been found to be disturbed in patients with schizophrenia. As schizophrenia is often linked to the prefrontal
cortex, it is perhaps not surprising that schizophrenic patients often also exhibit impairment in working memory.
Working memory provides a kind of cognitive workspace, likely a part of a global workspace, in which we can combine current
perceptions with past memory, so it is a strong candidate for part of what forms our subjective experience of time.
Schizophrenia has recently been described as a breakdown of connectivity, where there is both a loss of connection
between large, distant brain areas and also a randomisation in existing connections.
As our sense of time is a built up combination from across different sensory modalities, and schizophrenia is a breakdown in integration,
temporal awareness is broken down in schizophrenic subjects in a way which does not exhibit a clear trend.
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