By: Bart Maracewicz

Established Mechanisms


Cognitive Biases


Cognitive biases are replicable patterns in cognition that can result in inaccurate judgements, illogical interpretations, or perceptual distortions. Several cognitive biases exist in pre-Schizophrenics that can ultimately lead and contribute to the pathology of schizophrenia. One prominent bias that is an underlying psychological component of the illness is known as the “jump to conclusion” bias[1] . To demonstrate this, individuals diagnosed with schizophrenia were compared to a non-deluded control group in a probabilistic interference task. The probabilistic interference task consisted of participants observing the draw of coloured beads from two jars. Each pair of jars contained beads of different colours in different proportions. For example, one jar contained 100 beads of colour black and yellow, with 85 yellow beads and 15 black beads. The second jar contained 100 beads of black and yellow, but with 85 black beads and 15 yellow beads.

The participants were to make a decision (based on past draws) of whether or not they could stop the draw and confidently assume which colour would be drawn from which jar, or whether they would prefer to continue drawing items. Also, the individuals were asked to report a probability behind the draw of each colour from each jar, and how this value changed with subsequent draws. It was observed that schizophrenics requested fewer items (fewer draws) before reaching a conclusion – some reaching a decision after just one item being drawn. Target participants also demonstrated a higher likelihood of changing their guess confidence after receiving conflicting information (from a subsequent draw) compared to the control group.

The results of the study indicate that deluded individuals, like those diagnosed with Schizophrenia, are likely to base their cognitions, decisions, and actions on incomplete information. The pathology arises because of the impulsive processing that occurs at the cognitive level, leading to a bias that reaches conclusions before they are appropriate. Cognitive biases also contribute to the intensity and salience of already-present delusions and hallucinations. This mechanism suggests that, in some types of treatment of schizophrenia, it may be useful to intervene at the level of cognition, with the therapist working with the patient towards controlling and limiting the prevalence of biases in cognition, such as the impulse to jump to conclusions.

Affective Reactivity

Some patients diagnosed with schizophrenia have a higher level of activation in response to negative affect, which can lead to exacerbation of symptoms[2] . Particularly, the exacerbated schizophrenic symptoms can manifest themselves in a disturbance in communication[3] . To test this, individuals diagnosed with schizophrenia were subjected to conversation topics that induced an either a positive or negative affect in the individual. The conversations were recorded and analyzed using the Communication Disturbance Index (CDI), which measures disturbances in communication of meaning (referential disturbances, missing reference information, incorrect references). Individuals affected by Schizophrenia were shown to be highly sensitive to the stressful, negative-affect topics of conversation and this sensitivity manifested itself as a reduced ability to perform communicatively[4] .

The mismanagement of negative affect has been demonstrated in neuroimaging studies looking at the neurological correlates in schizophrenia. Individuals with schizophrenia, when shown emotionally salient images, show atypical neural activity in the right ventral striatum and bilateral amygdala, and exhibit less modulation of the visual cortex[5] . Similarly, schizophrenic subjects exhibit atypical phenotype when exposed to emotionally-salient stimuli. When shown affect-elicting stimuli (positive and negative), schizophrenics fail to evoke facial expressions [6] .

Evidence of affective reactivity in schizophrenics shows that the problems are not simply due to the sensitivity or insensitivity to certain emotional experiences – the emotional responsiveness in schizophrenia is not simply turned up or down. The ability to react emotionally is completely mismanaged, which generates a lack of a response in some cases, or an abnormal symptomatic manifestation in others. This provides a separate venue for treatment of the pathology, with therapy including the education of emotional management interventions and strategies to compensate for the maladapted responses.

Current Research

Childhood Trauma

HPA.jpg
HPA-axis: pathway and involved hormones.
Stress experienced in early childhood can result in the development of psychosis later in life. This is particularly true when the stress contains an intent to harm, as is seen in sexual, physical, emotional abuse, as well as in cases of neglect[7] [8] . Analysis of the
childhood_trauma.jpg
Risk factors for developing schizophrenia increase with intent-to-harm childhood trauma.
Environmental Risk Longitudinal study, which followed the development of 2,232 British children, allowed clinicians to determine types of trauma that were more associated with the development of psychosis later in life. In children as young as 12 years old, a high correlation was observed between the development of psychotic symptoms and childhood trauma. Maltreatment by adults and bullying by peers are strongly associated with reports of psychotic symptoms[9] . Importantly, this effect is true for children who experience adversity both in early and late childhood, is similar when there is intention to harm, and is independent of effects from socioeconomic status, intelligence, early psychopathology, and an overall genetic susceptibility to general psychopathic illnesses.
Alteration of the HPA axis is associated with both early experiences of trauma [10] ­and psychotic illnesses. Thus, it has been suggested that the development of schizophrenia is associated with the neurodevelopmental changes that occur with chronic overactivity of the hypothalamic-pituitary-adrenal HPA axis during stressful events during childhood [11] . The Traumagenic Neurodevelopmental model, which was developed to show the association between HPA axis activity and the development of schizophrenia, is based on findings that the differences seen in the brains of schizophrenic adults can also be observed in children who have experienced severe trauma [12] .


Mental Imagery

mental_imagery.jpg
Mental imagery can affect how situations are appraised and how decisions are based based on these appraisals.
Mental imagery is the generation of a perceptual experience that exists in the absence of a sufficient physical stimulus
[13] and involves the underlying psychological mechanisms of memory and perception. Fifty-two individuals diagnosed with schizophrenia according to the DSM-IV criteria were analyzed. The cognitive mental imagery questionnaire (QMI) was used to analyze the vividness of mental imagery across all sensory modalities between schizophrenic and control participants. This scale involves the rating of vividness on a scale of 1(perceiving imagery perfectly clearly, as if real) to 7(can think about imagery, but not imagine it). It has been found that individuals diagnosed with pathologies across the schizophrenia spectrum showed a higher vividness of mental imagery, and individuals diagnosed with high-schizotypy disorders experienced higher vividness than individuals with low-schizotypy[14] . Furthermore, it was observed that the increased mental imagery was observed across all sensory modalities. Despite mental imagery is more vivid in schizophrenia, it is independent of hallucinations and cognitive abilities, suggesting mental imagery is unrelated to the cognitive biases and hallucinations found in schizophrenia.

Negative Affective Priming

negative_affective_priming.jpg
An experimental trial: affective priming followed by a social judgement task.
In order to make successful social interactions, an individual must make accurate judgements in response to social cues. These social cues are highly influenced by affective information (internal and external) which must be controlled in order to make effective and appropriate social judgments. When individuals are given positive, neutral, or negative affective primes and are subsequently asked to rate the trustworthiness of a face, they judge faces to be less trustworthy prior to receiving a negative prime. This suggests that in normal individuals, affective priming plays a role in how they make social judgements. Compared to unaffected individuals, people diagnosed with schizophrenia report the faces to be significantly less trustworthy following a negative prime[15] . This provides evidence that one of the psychological mechanisms underlying the pathology of schizophrenia is an exaggerated influence of negative affect over social judgement, which can contribute to the social deficits present in individuals with the disorder. Further, the extent to which the negative affective prime affects social judgments is significantly associated with the extent and severity of positive schizophrenic symptoms, especially feelings of persecution.

It is likely that another cognitive bias known as the interpretive bias – which includes evaluating evidence as such to support previous conceptions – is implicated in the negative affective priming affecting social judgements. Schizophrenics may hold the belief that others are inherently threatening or untrustworthy and, with the presence of a negative affective prime, default into confirming this belief. Since it is a psychological mechanism, this bias may be receptive to conventional therapy, like cognitive-behavioural therapy, in order to reduce the maladaptive belief and to ultimately benefit the affected individual. Through developing strategies for coping and stepping back from preconceived beliefs to analyze affective evidence more objectively, individuals affected by schizophrenia may be able to adjust their social judgments and perform more effectively in social situations.

A Doctor Who Hears Voices

A Doctor Who Hears Voices is a documentary that follows Ruth Wilson, a junior doctor experiencing auditory hallucinations. It portrays the struggle of living with schizophrenia, but potential psychological interventions aimed at the psychological mechanisms underlying the disorder.


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