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Change in IQ in schizophrenia patients and their siblings: a controlled longitudinal study

  • N. E. M. Van Haren (a1) (a2), D. S. Van Dam (a3), R. K. Stellato (a4) and Genetic Risk and Outcome of Psychosis (GROUP) investigators



Lower intelligence quotient (IQ) has frequently been reported in patients with schizophrenia. However, it is unclear whether IQ declines (further) after illness onset and what the familial contribution is to this change. Therefore, we investigate IQ changes during the course of illness in patients with non-affective psychosis, their siblings and controls.


Data are part of the longitudinal Genetic Risk and Outcome of Psychosis (GROUP) study in the Netherlands and Belgium. Participants underwent three measurements, each approximately 3 years apart. A total of 1022 patients with non-affective psychosis [illness duration: 4.34 (s.d. = 4.50) years], 977 of their siblings, and 565 controls had at least one measure of IQ (estimated from four subtests of the WAIS-III).


At baseline, IQ was significantly lower in patients (IQ = 97.8) and siblings (IQ = 108.2; p < 0.0001) than in controls (IQ = 113.0; p < 0.0001), and in patients as compared with siblings (p < 0.0001). Over time, IQ increased in all groups. In siblings, improvement in IQ was significantly more pronounced (+0.7 points/year) than in patients (+0.5 points/year; p < 0.0001) and controls (+0.3 points/year; p < 0.0001). IQ increase was not significantly correlated with improvement in (sub)clinical outcome in any of the groups.


During the first 10 years of the illness, IQ increases to a similar (and subtle) extent in a relatively high-functioning group of schizophrenia patients and controls, despite the lower IQ in patients at baseline. In addition, the siblings’ IQ was intermediate at baseline, but over time the increase in IQ was more pronounced.


Corresponding author

Author for correspondence: N. E. M. Van Haren, E-mail:


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Contributed equally.

Genetic Risk and Outcome of Psychosis (GROUP) Investigators.

GROUP investigators are: Behrooz Z. Alizadeha,b, Therese van Amelsvoortc, Agna A. Bartels-Velthuisa, Nico J. van Beverend,e,f, Richard Bruggemana,g, Wiepke Cahnh,i, Lieuwe de Haanj,k, Philippe Delespaulc, Carin J. Meijerk, Inez Myin-Germeysl, Rene S. Kahnh,m, Frederike Schirmbeckk,n, Claudia J. P. Simonsc,o, Jim van Osc,h,p, Ruud van Winkell,c, Jurjen J. Luykxq,r

aUniversity of Groningen, University Medical Center Groningen, University Center for Psychiatry, Rob Giel Research center, Groningen, The Netherlands;

bUniversity of Groningen, University Medical Center Groningen, Department of Epidemiology, Groningen, The Netherlands;

cMaastricht University Medical Center, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht, The Netherlands;

dAntes Center for Mental Health Care, Rotterdam, The Netherlands;

eErasmus MC, Department of Psychiatry, Rotterdam, The Netherlands;

fErasmus MC, Department of Neuroscience, Rotterdam, The Netherlands;

gUniversity of Groningen, Department of Clinical and Developmental Neuropsychology, Groningen, The Netherlands;

hUniversity Medical Center Utrecht, Department of Psychiatry, Brain Centre Rudolf Magnus, Utrecht, The Netherlands;

iAltrecht, Mental Health Care, Utrecht, The Netherlands;

jAmsterdam UMC, University of Amsterdam, Department of Psychiatry, Amsterdam, The Netherlands;

kArkin, Institute for Mental Health, Amsterdam, The Netherlands;

lKU Leuven, Department of Neuroscience, Research Group Psychiatry, Center for Contextual Psychiatry, Leuven, Belgium;

mDepartment of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY

nAcademic Medical Center, University of Amsterdam, Department of Psychiatry, Amsterdam, The Netherlands;

oGGzE, Institute for Mental Health Care Eindhoven, Eindhoven, The Netherlands;

pKing's College London, King's Health Partners, Department of Psychosis Studies, Institute of Psychiatry, London, UK;

qUniversity Medical Center Utrecht, Department of Psychiatry, Brain Centre Rudolf Magnus, Utrecht University, Utrecht, The Netherlands;

rUniversity Medical Center Utrecht, Department of Translational Neuroscience, Brain Center Rudolf Magnus, Utrecht, The Netherlands



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Agnew-Blais, J and Seidman, LJ (2013) Neurocognition in youth and young adults under age 30 at familial risk for schizophrenia: a quantitative and qualitative review. Cognitive Neuropsychiatry 18, 4482.
American Psychiatric Association (2000) Diagnostic and Statistical Manual of Mental Disorders. 4th Edn. Text revision (DSM-IV-TR). Washington, DC: American Psychiatric Association.
Aylward, E, Walker, E and Bettes, B (1984) Intelligence in schizophrenia: meta-analysis of the research. Schizophrenia Bulletin 10, 430459.
Bartels, C, Wegrzyn, M, Wiedl, A, Ackermann, V and Ehrenreich, H (2010) Practice effects in healthy adults: a longitudinal study on frequent repetitive cognitive testing. BMC Neuroscience 11, 118.
Bora, E and Murray, RM (2014) Meta-analysis of cognitive deficits in ultra-high risk to psychosis and first-episode psychosis: do the cognitive deficits progress over, or after, the onset of psychosis? Schizophrenia Bulletin 40, 744755.
Bouchard, TJ (2009) Genetic influence on human intelligence (Spearman's g): how much? Annals of Human Biology 36, 527544.
Bozikas, VP and Andreou, C (2011) Longitudinal studies of cognition in first episode psychosis: a systematic review of the literature. The Australian & New Zealand Journal of Psychiatry 45, 93108.
Catron, DW (1978) Immediate test-retest changes in WAIS scores among college males. Psychological Report 43, 279290.
Colom, R, Karama, S, Jung, RE and Haier, RJ (2010) Human intelligence and brain networks. Dialogues of Clinical Neuroscience 12, 489501.
Dickerson, F, Stallings, C, Vaughan, C, Origoni, A, Khushalani, S, Dickinson, D and Medoff, D (2011) Cognitive functioning in recent onset psychosis. The Journal of Nervous and Mental Disease 199, 367371.
Dickson, H, Laurens, KR, Cullen, AE and Hodgins, S (2012) Meta-analyses of cognitive and motor function in youth aged 16 years and younger who subsequently develop schizophrenia. Psychological Medicine 42, 743755.
Fuller, R, Nopoulos, P, Arndt, S, O'Leary, D, Ho, BC and Andreasen, NC (2002) Longitudinal assessment of premorbid cognitive functioning in patients with schizophrenia through examination of standardized scholastic test performance. The American Journal of Psychiatry 159, 11831189.
Granholm, E, Link, P, Fish, S, Kraemer, H and Jeste, D (2010) Age-related practice effects across longitudinal neuropsychological assessments in older people with schizophrenia. Neuropsychology 24, 616624.
Groom, MJ, Jackson, GM, Calton, TG, Andrews, HK, Bates, AT, Liddle, PF and Hollis, C (2008) Cognitive deficits in early-onset schizophrenia spectrum patients and their non-psychotic siblings: a comparison with ADHD. Schizophrenia Research 99, 8595.
Harvey, PD (2001) Cognitive impairment in elderly patients with schizophrenia: age related changes. International Journal of Geriatric Psychiatry 16(suppl. 1), S78S85.
Harvey, PD, Reichenberg, A, Bowie, CR, Patterson, TL and Heaton, RK (2010) The course of neuropsychological performance and functional capacity in older patients with schizophrenia: influences of previous history of long-term institutional stay. Biological Psychiatry 67, 933939.
Hausknecht, JP, Halpert, JA, Di Paolo, NT and Moriarty Gerrard, MO (2007) Retesting in selection: a meta-analysis of coaching and practice effects for tests of cognitive ability. The Journal of Applied Psychology 92, 7385.
Hedman, AM, van Haren, NE, van Baal, GC, Brans, RG, Hijman, R, Kahn, RS and Hulshoff Pol, HE (2012) Is there change in intelligence quotient in chronically ill schizophrenia patients? A longitudinal study in twins discordant for schizophrenia. Psychological Medicine 42, 25352541.
Hedman, AM, van Haren, NE, van Baal, CG, Kahn, RS and Hulshoff Pol, HE (2013) IQ change over time in schizophrenia and healthy individuals: a meta-analysis. Schizophrenia Research 146, 201208.
Heinrichs, RW and Zakzanis, KK (1998) Neurocognitive deficit in schizophrenia: a quantitative review of the evidence. Neuropsychology 12, 426445.
Hochberger, WC, Combs, T, Reilly, JL, Bishop, JR, Keefe, RSE, Clementz, BA, Keshavan, MS, Pearlson, GD, Tamminga, CA, Hill, SK and Sweeney, JA (2018) Deviation from expected cognitive ability across psychotic disorders. Schizophrenia Research 192, 300307.
Irani, F, Kalkstein, S, Moberg, EA and Moberg, PJ (2011) Neuropsychological performance in older patients with schizophrenia: a meta-analysis of cross-sectional and longitudinal studies. Schizophrenia Bulletin 37, 13181326.
Kahn, RS and Keefe, RSE (2013) Schizophrenia is a cognitive illness: time for a change in focus. JAMA Psychiatry 70, 11071112.
Kay, SR, Fiszbein, A and Opler, LA (1987) The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophrenia Bulletin 13, 261276.
Keefe, RSE and Fenton, WS (2007) How should DSM-V criteria for schizophrenia include cognitive impairment? Schizophrenia Bulletin 33, 912920.
Kendler, KS, Ohlsson, H, Sundquist, J and Sundquist, K (2015) IQ and schizophrenia in a Swedish national sample: their causal relationship and the interaction of IQ with genetic risk. American Journal of Psychiatry 172, 17.
Kendler, KS, Ohlsson, H, Mezuk, B, Sundquist, JO and Sundquist, K (2016) Observed cognitive performance and deviation from familial cognitive aptitude at age 16 years and ages 18 to 20 years and risk for schizophrenia and bipolar illness in a Swedish national sample. JAMA Psychiatry 73, 465471.
Khandaker, GM, Barnett, JH, White, IR and Jones, PB (2011) A quantitative meta-analysis of population-based studies of premorbid intelligence and schizophrenia. Schizophrenia Research 132, 220227.
Kirkpatrick, B, Messias, E, Harvey, PD, Fernandez-Egea, E and Bowie, CR (2008) Is schizophrenia a syndrome of accelerated aging? Schizophrenia Bulletin 34, 10241032.
Korver, N, Quee, PJ, Boos, HB, Simons, CJ and de Haan, L, GROUP investigators (2012) Genetic Risk and Outcome of Psychosis (GROUP), a multi-site longitudinal cohort study focused on gene-environment interaction: objectives, sample characteristics, recruitment and assessment methods. International Journal of Methods in Psychiatric Research 21, 205221.
Kraepelin, E (1896) Psychiatrie (8th edn.). Reprinted (1971) in parts as Dementia Praecox and Paraphrenia (trans. R.M. Barclay).
Kremen, WS, Buka, SL, Seidman, LJ, Goldstein, JM, Koren, D and Tsuang, MT (1998) IQ decline during childhood and adult psychotic symptoms in a community sample: a 19-year longitudinal study. The American Journal of Psychiatry 155, 672677.
Kubota, M, van Haren, NE, Haijma, SV, Schnack, HG, Cahn, W, Hulshoff Pol, HE and Kahn, RS (2015) Association of IQ changes and progressive brain changes in patients with schizophrenia. JAMA Psychiatry 72, 803812.
Kurtz, MM (2005) Neurocognitive impairment across the lifespan in schizophrenia: an update. Schizophrenia Research 74, 1526.
Maziade, M, Rouleau, N, Gingras, N, Boutin, P, Paradis, ME, Jomphe, V, Boutin, J, Létourneau, K, Gilbert, E, Lefebvre, AA, Doré, MC, Marino, C, Battaglia, M, Mérette, C and Roy, MA (2009) Shared neurocognitive dysfunctions in young offspring at extreme risk for schizophrenia or bipolar disorder in eastern Quebec multigenerational families. Schizophrenia Bulletin 35, 919930.
Maziade, M, Rouleau, N, Mérette, C, Cellard, C, Battaglia, M, Marino, C, Jomphe, V, Gilbert, E, Achim, A, Bouchard, RH, Paccalet, T, Paradis, ME and Roy, MA (2011) Verbal and visual memory impairments among young offspring and healthy adult relatives of patients with schizophrenia and bipolar disorder: selective generational patterns indicate different developmental trajectories. Schizophrenia Bulletin 37, 12181228.
McIntosh, AM, Gow, A, Luciano, M, Davies, G, Liewald, DC, Harris, SE, Corley, J, Hall, J, Starr, JM, Porteous, DJ, Tenesa, A, Visscher, PM and Deary, IJ (2013) Polygenic risk for schizophrenia is associated with cognitive change between childhood and old age. Biological Psychiatry 73, 938943.
Meier, MH, Caspi, A, Reichenberg, A, Keefe, RS, Fisher, HL, Harrington, H, Houts, R, Poulton, R and Moffitt, TE (2014) Neuropsychological decline in schizophrenia from the premorbid to the postonset period: evidence from a population-representative longitudinal study. The American Journal of Psychiatry 171, 91101.
Mesholam-Gately, RI, Giuliano, AJ, Goff, KP, Faraone, SV and Seidman, LJ (2009) Neurocognition in first-episode schizophrenia: a meta-analytic review. Neuropsychology 23, 315336.
Mollon, J and Reichenberg, A (2018) Cognitive development prior to onset of psychosis. Psychological Medicine 48, 392403.
Mollon, J, David, AS, Zammit, S, Lewis, G and Reichenberg, A (2018) Course of cognitive development from infancy to early adulthood in the psychosis spectrum. JAMA Psychiatry 75, 270.
O'Connor, JA, Wiffen, BD, Reichenberg, A, Aas, M, Falcone, MA, Russo, M, Sood, PG, Taylor, H and David, AS (2012) Is deterioration of IQ a feature of first episode psychosis and how can we measure it? Schizophrenia Research 137, 104109.
Pinheiro, JC, DebRoy, SD, Bates, DJ and Sakar, D (2012) nlme: Linear and Nonlinear Mixed Effects Models. (R package version 3.1-105.).
Posthuma, D, de Geus, EJ and Boomsma, DI (2001) Perceptual speed and IQ are associated through common genetic factors. Behavior Genetics 31, 593602.
Rapoport, JL and Gogtay, N (2011) Childhood onset schizophrenia: support for a progressive neurodevelopmental disorder. International Journal of Developmental Neuroscience 29, 251258.
Reichenberg, A, Weiser, M, Rapp, MA, Rabinowitz, J, Caspi, A, Schmeidler, J, Knobler, HY, Lubin, G, Nahon, D, Harvey, PD and Davidson, M (2005) Elaboration on premorbid intellectual performance in schizophrenia: premorbid intellectual decline and risk for schizophrenia. Archives of General Psychiatry 62, 12971304.
Rund, BR (1998) A review of longitudinal studies of cognitive functions in schizophrenia patients. Schizophrenia Bulletin 24, 425435.
Stirling, J, White, C, Lewis, S, Hopkins, R, Tantam, D, Huddy, A and Montague, L (2003) Neurocognitive function and outcome in first-episode schizophrenia: a 10-year follow-up of an epidemiological cohort. Schizophrenia Research 65, 7586.
Szoke, A, Trandafir, A, Dupont, ME, Méary, A, Schürhoff, F and Leboyer, M (2008) Longitudinal studies of cognition in schizophrenia: meta-analysis. British Journal of Psychiatry 192, 248257.
Toulopoulou, T, Picchioni, M, Rijsdijk, F, Hua-Hall, M, Ettinger, U, Sham, P and Murray, R (2007) Substantial genetic overlap between neurocognition and schizophrenia. Archives of General Psychiatry 64, 13481355.
Toulopoulou, T, van Haren, N, Zhang, X, Sham, PC, Cherny, SS, Campbell, DD, Picchioni, M, Murray, R, Boomsma, DI, Hulshoff Pol, HE, Brouwer, R, Schnack, H, Fañanás, L, Sauer, H, Nenadic, I, Weisbrod, M, Cannon, TD and Kahn, R (2014) Reciprocal causation models of cognitive vs volumetric cerebral intermediate phenotypes for schizophrenia in a pan-European twin cohort. Molecular Psychiatry 20, 111.
Ullman, VZ, Hornik-Lurie, T and Reichenberg, A (2017) A population-based study of premorbid scholastic achievement among patients with psychiatric disorders. Psychiatry Research 253, 281286.
van Haren, NEM, Hulshoff Pol, HE, Schnack, HG, Cahn, W, Brans, R, Carati, I, Rais, M and Kahn, R (2008) Progressive brain volume loss in schizophrenia over the course of the illness: evidence of maturational abnormalities in early adulthood. Biological Psychiatry 63, 106113.
van Oel, CJ, Sitskoorn, MM, Cremer, MP and Kahn, RS (2002) School performance as a premorbid marker for schizophrenia: a twin study. Schizophrenia Bulletin 28, 401414.
Vollema, MG and Ormel, J (2000) The reliability of the structured interview for schizotypy-revised. Schizophrenia Bulletin 26, 619629.
Walters, JTR and Owen, MJ (2007) Endophenotypes in psychiatric genetics. Molecular Psychiatry 12, 886890.
Wechsler, D (1997) WAIS-III: Wechsler Adult Intelligence Scale (3rd edn). Administration and Scoring Manual. San Antonio, TX: Psychological Corporation.
Woodberry, KA, Giuliano, AJ and Seidman, LJ (2008) Premorbid IQ in schizophrenia: a meta-analytic review. American Journal of Psychiatry 165, 579587.
World Health Organization (1997) Composite International Diagnostic Interview (CIDI). Version 2.1.
Zipursky, RB, Reilly, TJ and Murray, RM (2013) The myth of schizophrenia as a progressive brain disease. Schizophrenia Bulletin 39, 13631372.


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Change in IQ in schizophrenia patients and their siblings: a controlled longitudinal study

  • N. E. M. Van Haren (a1) (a2), D. S. Van Dam (a3), R. K. Stellato (a4) and Genetic Risk and Outcome of Psychosis (GROUP) investigators


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