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Schizophrenia
Figure 2: Stress-vulnerability Model of Positive Symptom Formation Adapted to Identified Psychosis-proneness Factors in 22q11DS
Cerebral regional: Cerebral global:
Local structure Grey and white matter
alterations deficits
Genes
Environmental factors
Cortico–cortical Cortical thickness
COMT
Social isolation
connectivity Maturation processes
PRODH
TBX1
Precipitants
Emotional factors
Cognitive dysfunctions
Anomalous
Anxiety
experiences/
Depression
arousal
Metacognitive beliefs Specific:
Self-monitoring deficits
General:
Executive functions
Search
Attention
for
Verbal memory
meaning
Verbal skills
Positive
schizotypy
Delusional beliefs
At the top are the precipitant factors of environmental, cerebral and genetic origin. To the right are the cognitive dysfunctions identified in youngsters with 22q11DS as contributing to the
emergence of psychotic symptoms. To the left are the emotional factors implicated in the formation and maintenance of positive schizotypic manifestations in the deletion syndrome.
between these precipitant factors. Youngsters with the deletion threat-related content to persecutory delusions, while feelings of
carrying the low-activity catecho-o-methyltransferase gene (COMTL), being punished for intrinsic badness can originate from poor self-
who may be exposed to increased levels of dopamine in the prefrontal esteem.
57
The presence of emotional disorders, as evidenced in
cortex, appear to be more liable to psychotic disorders.
17
The authors children and adolescents with 22q11DS,
58
intimates the activity of
further observe an association between COMTL and reduced cerebral depressive and anxiety-laden metacognitive beliefs about the self and
grey matter volume in the dorsolateral prefrontal cortex, leading to the the environment in these youngsters. Evidencing an interaction
emergence of psychotic symptoms during late adolescence.
53
More between positive schizotypy symptoms and psychological distress in
recently, Gothelf et al.
17
observed that COMT genotype, verbal IQ 22q11DS may also signal the reinforcing effect symptoms of delusions
(VIQ) decrease and anxiety/depression score as measured by the Child and hallucinations exercise on threat-related beliefs and negative
Behaviour Checklist – Parent Version (CBCL)
54
combine to predict 54% schemas about the self. In turn, reinforced beliefs can retroactively
of the variance of the Brief Psychiatric Rating Scale (BPRS)
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total score. promote further psychological distress and potentiality for the
Interestingly, the COMT genotype, VIQ decrease and CBCL expression of positive schizotypy symptoms (see Figure 2). Both clinical
anxiety/depression score respectively correspond to precipitant studies with 22q11DS adolescents found increased social isolation in
dysfunction, cognitive dysfunction and emotional factors in the stress- relation to positive schizotypic manifestations in youths with the
vulnerability model. Gothelf and colleagues also explored significant deletion syndrome.
20,25
This may be indicative that youngsters with
interactions between these factors and baseline psychotic symptoms. delusions interpret social interactions in a way that increases
With regard to emotional factors, the authors found that the “baseline delusional distress, which in turn promotes social withdrawal. Future
anxiety/depression scores x the baseline psychotic symptoms scores” research on metacognitive beliefs in 22q11DS may hold interesting
interaction significantly predicted BPRS scores at follow-up. While the clues to our understanding of psychosis-proneness and the unfolding
authors interpreted these results as conveying a specific genetic of positive symptoms in youngsters with the deletion syndrome.
predisposition to a psychiatric phenotype, the question of why
baseline emotional factors should interact with baseline psychotic Conclusions
manifestations remains untouched. In this selective review, we wished to examine the basic factors that
lead to the manifestations of positive symptoms of psychosis in
Complementary interpretations may focus on the nature of the youngsters with 22q11DS. We only briefly touched on the genetic
interactions between emotional factors and positive symptoms factors, reviewed elsewhere in the literature.
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Instead, we focused on
of psychosis. According to Freeman and colleagues, the content of reuniting the evidence from studies reporting schizophrenic-like
positive symptoms reflects the emotional perturbations of the symptoms, neuroanatomical alterations, emotional disorders and
individual.
56
For example, important feelings of anxiety can provide cognitive dysfunctions in youths with 22q11DS, and on proposing a
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