People with schizophrenia, and possibly forensic personality disorders populations, demonstrate a range of reading skills deficits

Reading skills deficits in people with mental illness: A systematic review and meta-analysis. Martina Vanova et al. European Psychiatry, Volume 64 Issue 1, November 3 2020. https://www.cambridge.org/core/journals/european-psychiatry/article/reading-skills-deficits-in-people-with-mental-illness-a-systematic-review-and-metaanalysis/2EE4FD903FF4FA7FED80B8DC62E18E62

Abstract

Background: Good reading skills are important for appropriate functioning in everyday life, scholastic performance, and acquiring a higher socioeconomic status. We conducted the first systematic review and meta-analysis to quantify possible deficits in specific reading skills in people with a variety of mental illnesses, including personality disorders (PDs).

Methods: We performed a systematic search of multiple databases from inception until February 2020 and conducted random-effects meta-analyses.

Results: The search yielded 34 studies with standardized assessments of reading skills in people with one or more mental illnesses. Of these, 19 studies provided data for the meta-analysis. Most studies (k = 27; meta-analysis, k = 17) were in people with schizophrenia and revealed large deficits in phonological processing (Hedge’s g = −0.88, p < 0.00001), comprehension (Hedge’s g = −0.96, p < 0.00001) and reading rate (Hedge’s g = −1.22, p = 0.002), relative to healthy controls; the single-word reading was less affected (Hedge’s g = −0.70, p < 0.00001). A few studies in affective disorders and nonforensic PDs suggested weaker deficits (for all, Hedge’s g < −0.60). In forensic populations with PDs, there was evidence of marked phonological processing (Hedge’s g = −0.85, p < 0.0001) and comprehension deficits (Hedge’s g = −0.95, p = 0.0003).

Conclusions: <. Future studies are needed to establish how these deficits directly compare to those seen in developmental or acquired dyslexia and to explore the potential of dyslexia interventions to improve reading skills in these populations.

Discussion

This systematic review and meta-analysis evaluated existing evidence to identify the type and degree of reading impairments in different MIs, the reading assessment tools that might most consistently detect them, and possible differences in the pattern of reading skills deficits in people with different MIs in forensic and nonforensic settings. Most of the reviewed studies (27/34) included people with SZ. There were seven studies of reading skills deficits in people with different MIs (PD or general MI) in forensic settings. Our findings are discussed below.

Effect of diagnosis in nonforensic samples

We observed significant deficits in multiple reading skills in SZ, resembling the pattern typically seen in dyslexia [6], and consistent with previous evidence for shared genetic and psychophysiological traits in SZ and dyslexia [7]. In our meta-analysis, both phonological processing and comprehension were greatly impaired. These impairments may be associated with ineffective use of contextual information [91] and contribute to poor speech in SZ, especially in close association with thought disorder [92]. Reading rate was low but the deficit in reading accuracy was lower. This indicates relatively preserved single-word reading skills, most likely because they are usually acquired before illness onset and remain intact [47]. In contrast, there was evidence for impairments in vocabulary and spelling, presumably as a result of disrupted scholastic experience. Disrupted scholastic experience during adolescence can affect complex skills such as comprehension [44,45,47], which could precipitate difficulties with processing complex written information in SZ. People with SZ showed reading skills well below their achieved education level (see Education). Reading skills deficits in SZ also do not seem to be explained by other aspects of cognition (see Cognitive Function) although more comprehensive investigations are needed to substantiate this. Our findings (Symptoms and Medication) further indicated that while symptoms and high antipsychotic doses may worsen reading skills, they do not fully explain the profile of reading skills deficits in SZ. Impairment in comprehension and vocabulary was present even before the onset of symptoms [44,45] together with deficient phonological processing, which has been related to disrupted visual processing in SZ since early age [21]. The symptoms can, however, aggravate deficits in reading skills, such as comprehension, which are acquired with experience, and also depend on the earlier acquired skills [93]. Recent data [94] suggest that some aspects of language production (e.g., slower articulation) that can affect reading skills assessments are particularly sensitive to dopamine-D2 receptor blocking antipsychotics. Furthermore, most studies in SZ included more men than women or men solely and also included people with schizoaffective disorder. Further studies need to comprehensively examine specific reading skills in both men and women with schizophrenia and schizoaffective disorder (separately) while taking medication, symptoms, cognition, education, and socioeconomic status into account.

Unlike in SZ and psychosis [51,58,65], nonpsychotic bipolar disorder, and affective disorders, seemed to have comprehension and single-word reading skills comparable to HC [30,47]. Although not all studies specified the type of PD, it seems that reading skill deficits may not be as prominent in nonforensic psychopathy as in SZ.

Effect of diagnosis in forensic samples

Our findings suggest only a weak or no deficit in nonforensic psychopathy but indicate a marked phonological processing and comprehension deficit in the incarcerated group. It is possible that PD/psychopathic individuals with good phonological processing and comprehension are more able to evade incarceration [30,95]. Nonetheless, marked reading deficits in the incarcerated group may have contributed to their poor adjustment within the community [27], which, in turn, increased the risk of incarceration. Men with MIs within forensic settings had significantly lower general reading abilities and spelling than women with MIs [27], consistent with the pattern seen in healthy samples [22].

Clinical implications

Comprehension has a significant influence on decision-making capacity in SZ [96], and this is likely to be true also for people with other MIs, especially within forensic populations. Dyslexia is often underdiagnosed in people with MIs, and this might explain their inability to complete higher education and obtain jobs [15], or the expression of socially unacceptable behaviors [27]. Furthermore, progression and engagement in therapeutic activities within mental health services often depend on good reading and language skills. This highlights a need to accurately identify reading deficits and develop specific programs to improve reading skills of people in psychiatric services. It may be possible to target reading deficits in SZ and other MIs by building on the less affected aspects, such as lexical knowledge (access to words) [97,98], and access to familiar information that can compensate for some of the reading deficits [99], while implementing interventions to ameliorate reading skills [100].

Effect of assessments

Significant between-test differences were found only in tests detecting deficits in comprehension, accuracy, and rate in SZ. In comprehension and rate, the NDRT and GORT-4, and in accuracy, the GORT solely, consistently detected large deficits while the Alouette (French) test detected no deficits (Figure 2). It is conceivable that certain deficits emerge more often/strongly in English compared to some other languages, as is the case in developmental dyslexia [101]. This possibility requires further study.