ABSTRACT
Objective: To critically analyze the evidence regarding changes in verbal and performance intelligence quotient (IQ) in patients with schizophrenia.
Data Sources: An English-language–only search was conducted in the PubMed, Cochrane Library, and LILACS databases for articles with study objectives that included Wechsler Adult Intelligence Scale (WAIS) assessment of cognitive functions in patients with schizophrenia. Descriptors were defined based on Medical Subject Headings, where associations of psychotic disorders related to the schizophrenia spectrum were suggested, as well as the “Wechsler Scales” descriptor. The search was conducted in November 2022 with no restriction on the date of publication to select studies that used any of the WAIS editions.
Study Selection: Articles that met the inclusion criteria were selected after title and summary identification and full-text review.
Results: A total of 28 articles were identified. All studies presented total IQ scores, but only 20 showed results for verbal IQ (n = 20) or performance IQ (n = 19). Analyzed data indicated patients had average performance on verbal comprehension features but low average performance on perceptual reasoning, working memory, and processing speed indices.
Conclusions: Executive function deficits were found in the analyzed studies, which reflect difficulties in planning and impulse control—characteristics present in the diagnosis of schizophrenia. The identification of this neuropsychological functioning contributes to the understanding of the cognitive dynamics found in schizophrenia and may help in early diagnosis, reinforcing the hypothesis that cognitive performance may be one of the indicators of psychopathologic expression.
Prim Care Companion CNS Disord 2023;25(5):22r03456
Author affiliations are listed at the end of this article.
Free Access: Please Log In
This content is completely free—but you need to be logged in to read the full article. If you already have an account, please log in below. Otherwise, register for free to unlock instant access.
References (43)
- American Psychiatry Association. Diagnostic and Statistical Manual of Mental Disorders - DSM-5. Fifth Edition. Washington: American Psychiatric Association; 2013.
- Sideli L, Mule A, La Barbera D, et al. Do child abuse and maltreatment increase risk of schizophrenia? Psychiatry Investig. 2012;9(2):87–99. PubMed CrossRef
- Ruby E, Polito S, McMahon K, et al. Pathways associating childhood trauma to the neurobiology of schizophrenia. Front Psychol Behav Sci. 2014;3(1):1–17. PubMed
- Volk DW, Lewis DA. Rosenberg’s Molecular and Genetic Basis of Neurological and Psychiatric Disease. 5th ed. Academic Press; 2014.
- Nuechterlein KH, Barch DM, Gold JM, et al. Identification of separable cognitive factors in schizophrenia. Schizophr Res. 2004;72(1):29–39. PubMed CrossRef
- Callicott JH, Mattay VS, Bertolino A, et al. Physiological characteristics of capacity constraints in working memory as revealed by functional MRI. Cereb Cortex. 1999;9(1):20–26. PubMed CrossRef
- Heinrichs RW. The primacy of cognition in schizophrenia. Am Psychol. 2005;60(3):229–242. PubMed CrossRef
- Kudo N, Yamamori H, Ishima T, et al. Plasma levels of soluble tumor necrosis factor receptor 2 (sTNFR2) are associated with hippocampal volume and cognitive performance in patients with schizophrenia. Int J Neuropsychopharmacol. 2018;21(7):631–639. PubMed CrossRef
- Lin YT, Liu CM, Chiu MJ, et al. Differentiation of schizophrenia patients from healthy subjects by mismatch negativity and neuropsychological tests. PLoS One. 2012;7(4):e34454. PubMed CrossRef
- Lezak MD, Howieson DB, Loring DW, et al. Neuropsychological Assessment. 5th ed. Oxford University Press; 2014.
- Michel NM, Goldberg JO, Heinrichs RW, et al. WAIS-IV profile of cognition in schizophrenia. Assessment. 2013;20(4):462–473. PubMed CrossRef
- Wechsler D. Wechsler Adult Intelligence Scale: Technical and Interpretive Manual. 4th ed. San Antonio, TX: Psychological Corporation; 2008.
- Gold JM, Hurt SW. The effects of haloperidol on thought disorder and IQ in schizophrenia. J Pers Assess. 1990;54(1-2):390–400. PubMed
- Goldman RS, Axelrod BN, Tandon R, et al. Spurious WAIS-R cholinergic profiles in schizophrenia. Clin Neuropsychol. 1993;7(2):171–178. PubMed CrossRef
- Condray R, van Kammen DP, Steinhauer SR, et al. Language comprehension in schizophrenia: trait or state indicator? Biol Psychiatry. 1995;38(5):287–296. PubMed CrossRef
- Fujii DE, Ahmed I, Jokumsen M, et al. The effects of clozapine on cognitive functioning in treatment-resistant schizophrenic patients. J Neuropsychiatry Clin Neurosci. 1997;9(2):240–245. PubMed CrossRef
- Hawkins KA, Sullivan TE, Choi EJ. Memory deficits in schizophrenia: inadequate assimilation or true amnesia? findings from the Wechsler Memory Scale–revised. J Psychiatry Neurosci. 1997;22(3):169–179. PubMed
- Mortimer AM, Bowen K. Measuring IQ in schizophrenia research: an update of the Quick Test in estimating IQ decline. Cogn Neuropsychiatry. 1999;4(2):81–88. PubMed CrossRef
- Ilonen T, Taiminen T, Lauerma H, et al. Impaired Wisconsin card sorting test performance in first-episode schizophrenia: resource or motivation deficit? Compr Psychiatry. 2000;41(5):385–391. PubMed CrossRef
- Egan MF, Goldberg TE, Gscheidle T, et al. Relative risk for cognitive impairments in siblings of patients with schizophrenia. Biol Psychiatry. 2001;50(2):98–107. PubMed CrossRef
- Baron K, Hays JR. Characteristics of readmitted psychiatric inpatients. Psychol Rep. 2003;93(1):235–238. PubMed CrossRef
- Zakzanis KK, Andrikopoulos J, Young DA, et al. Neuropsychological differentiation of late-onset schizophrenia and dementia of the Alzheimer’s type. Appl Neuropsychol. 2003;10(2):105–114. PubMed CrossRef
- Nakano H, Terao T, Iwata N, et al. Symptomatological and cognitive predictors of insight in chronic schizophrenia. Psychiatry Res. 2004;127(1-2):65–72. PubMed CrossRef
- Hori H, Noguchi H, Hashimoto R, et al. Antipsychotic medication and cognitive function in schizophrenia. Schizophr Res. 2006;86(1-3):138–146. PubMed CrossRef
- Maeda K, Kasai K, Watanabe A, et al. Effect of subjective reasoning and neurocognition on medication adherence for persons with schizophrenia. Psychiatr Serv. 2006;57(8):1203–1205. PubMed CrossRef
- Mo S, Su Y, Chan RC, et al. Comprehension of metaphor and irony in schizophrenia during remission: the role of theory of mind and IQ. Psychiatry Res. 2008;157(1-3):21–29. PubMed CrossRef
- Stefanopoulou E, Lafuente AR, Saez Fonseca JA, et al. Insight, global functioning and psychopathology amongst in-patient clients with schizophrenia. Psychiatr Q. 2009;80(3):155–165. PubMed CrossRef
- Ozguven HD, Oner O, Baskak B, et al. Theory of mind in schizophrenia and Asperger’s syndrome: relationship with negative symptoms. Klinik Psikofarmakol Bulteni. 2010;20(1):5–13. PubMed CrossRef
- Lu W, Zhang C, Yi Z, et al. Association between BDNF Val66Met polymorphism and cognitive performance in antipsychotic-naïve patients with schizophrenia. J Mol Neurosci. 2012;47(3):505–510. PubMed CrossRef
- Rapp EK, White-Ajmani ML, Antonius D, et al. Schizophrenia comorbid with panic disorder: evidence for distinct cognitive profiles. Psychiatry Res. 2012;197(3):206–211. PubMed CrossRef
- Zhu X, Gu H, Liu Z, et al. Associations between TCF4 gene polymorphism and cognitive functions in schizophrenia patients and healthy controls. Neuropsychopharmacology. 2013;38(4):683–689. PubMed CrossRef
- Kao YC, Liu YP, Lien YJ, et al. The influence of sex on cognitive insight and neurocognitive functioning in schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry. 2013;44:193–200. PubMed CrossRef
- Fukumoto M, Hashimoto R, Ohi K, et al. Relation between remission status and attention in patients with schizophrenia. Psychiatry Clin Neurosci. 2014;68(3):234–241. PubMed CrossRef
- Dang J, Zhang J, Guo Z, et al. A pilot study of iPad-assisted cognitive training for schizophrenia. Arch Psychiatr Nurs. 2014;28(3):197–199. PubMed CrossRef
- El-Missiry A, Elbatrawy A, El Missiry M, et al. Comparing cognitive functions in medication adherent and non-adherent patients with schizophrenia. J Psychiatr Res. 2015;70:106–112. PubMed CrossRef
- Nilsson BM, Holm G, Ekselius L. Karolinska scales of personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls. Nord J Psychiatry. 2016;70(1):53–61. PubMed CrossRef
- Liang S, Deng W, Wang Q, et al. Performance of verbal fluency as an endophenotype in patients with familial versus sporadic schizophrenia and their parents. Sci Rep. 2016;6(1):32597. PubMed CrossRef
- Krukow P, Karakuła-Juchnowicz H, Juchnowicz D, et al. Processing speed is associated with differences in IQ and cognitive profiles between patients with schizophrenia and their healthy siblings. Nord J Psychiatry. 2017;71(1):33–41. PubMed CrossRef
- Moher D, Liberati A, Tetzlaff J, et al; PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7):e1000097. PubMed CrossRef
- Wang Q, Chan R, Sun J, et al. Reaction time of the continuous performance test is an endophenotypic marker for schizophrenia: a study of first-episode neuroleptic-naive schizophrenia, their non-psychotic first-degree relatives and healthy population controls. Schizophr Res. 2007;89(1-3):293–298. PubMed CrossRef
- Islam MA, Habtewold TD, van Es FD, et al; GROUP Investigators. Long-term cognitive trajectories and heterogeneity in patients with schizophrenia and their unaffected siblings. Acta Psychiatr Scand. 2018;138(6):591–604. PubMed CrossRef
- Heinrichs RW, Ammari N, Miles AA, et al. Cognitive performance and functional competence as predictors of community independence in schizophrenia. Schizophr Bull. 2010;36(2):381–387. PubMed CrossRef
- Hu M, Chen J, Li L, et al. Semantic fluency and executive functions as candidate endophenotypes for the early diagnosis of schizophrenia in Han Chinese. Neurosci Lett. 2011;502(3):173–177. PubMed CrossRef
Please sign in or purchase this PDF for $40.