Hostname: page-component-6bf8c574d5-8gtf8 Total loading time: 0 Render date: 2025-02-18T21:26:00.807Z Has data issue: false hasContentIssue false
  • English
  • Français

High educational performance is a distinctive feature of bipolar disorder: a study on cognition in bipolar disorder, schizophrenia patients, relatives and controls

Published online by Cambridge University Press:  01 December 2015

A. Vreeker ,
M. P. M. Boks ,
L. Abramovic ,
S. Verkooijen ,
A. H. van Bergen ,
M. H. J. Hillegers ,
A. T. Spijker ,
E. Hoencamp ,
E. J. Regeer  and
R. F. Riemersma-Van der Lek
...Show all authors
A. Vreeker
Affiliation:
Department of Psychiatry, University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, The Netherlands
M. P. M. Boks
Affiliation:
Department of Psychiatry, University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, The Netherlands
L. Abramovic
Affiliation:
Department of Psychiatry, University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, The Netherlands
S. Verkooijen
Affiliation:
Department of Psychiatry, University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, The Netherlands
A. H. van Bergen
Affiliation:
Department of Psychiatry, University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, The Netherlands
M. H. J. Hillegers
Affiliation:
Department of Psychiatry, University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, The Netherlands
A. T. Spijker
Affiliation:
Department of Mood Disorders, PsyQ, The Hague, The Netherlands Department of Mood Disorder, PsyQ Rijnmond, Rotterdam, The Netherlands
E. Hoencamp
Affiliation:
Parnassia BAVO Group, The Hague, The Netherlands Leiden University, Institute of Psychology, Leiden, The Netherlands
E. J. Regeer
Affiliation:
Altrecht Institute for Mental Health Care, Utrecht, The Netherlands
R. F. Riemersma-Van der Lek
Affiliation:
Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
A. W. M. M. Stevens
Affiliation:
Dimence Centre for Bipolar Disorders, Almelo, The Netherlands
P. F. J. Schulte
Affiliation:
Mental Health Services, Noord Holland Noord, Alkmaar, The Netherlands
R. Vonk
Affiliation:
Reinier van Arkel Group, ‘s-Hertogenbosch, The Netherlands
R. Hoekstra
Affiliation:
Delta Center for Mental Health Care, Rotterdam, The Netherlands
N. J. M. van Beveren
Affiliation:
Delta Center for Mental Health Care, Rotterdam, The Netherlands Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands
R. W. Kupka
Affiliation:
Altrecht Institute for Mental Health Care, Utrecht, The Netherlands Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands
R. M. Brouwer
Affiliation:
Department of Psychiatry, University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, The Netherlands
C. E. Bearden
Affiliation:
Semel Institute For Neuroscience and Human Behavior, University of California-Los Angeles, Los Angeles, California, USA Department of Psychology, University of California-Los Angeles, Los Angeles, California, USA
J. H. MacCabe
Affiliation:
Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
R. A. Ophoff
Affiliation:
Department of Psychiatry, University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, The Netherlands Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

Background

Schizophrenia is associated with lower intelligence and poor educational performance relative to the general population. This is, to a lesser degree, also found in first-degree relatives of schizophrenia patients. It is unclear whether bipolar disorder I (BD-I) patients and their relatives have similar lower intellectual and educational performance as that observed in schizophrenia.

Method

This cross-sectional study investigated intelligence and educational performance in two outpatient samples [494 BD-I patients, 952 schizophrenia spectrum (SCZ) patients], 2231 relatives of BD-I and SCZ patients, 1104 healthy controls and 100 control siblings. Mixed-effects and regression models were used to compare groups on intelligence and educational performance.

Results

BD-I patients were more likely to have completed the highest level of education (odds ratio 1.88, 95% confidence interval 1.66–2.70) despite having a lower IQ compared to controls (β = −9.09, s.e. = 1.27, p < 0.001). In contrast, SCZ patients showed both a lower IQ (β = −15.31, s.e. = 0.86, p < 0.001) and lower educational levels compared to controls. Siblings of both patient groups had significantly lower IQ than control siblings, but did not differ on educational performance. IQ scores did not differ between BD-I parents and SCZ parents, but BD-I parents had completed higher educational levels.

Conclusions

Although BD-I patients had a lower IQ than controls, they were more likely to have completed the highest level of education. This contrasts with SCZ patients, who showed both intellectual and educational deficits compared to healthy controls. Since relatives of BD-I patients did not demonstrate superior educational performance, our data suggest that high educational performance may be a distinctive feature of bipolar disorder patients.

Keywords

Bipolar disordercognitioneducational performancefamilial vulnerabilityintelligenceIQschizophrenia
Type
Original Articles
Information
Psychological Medicine , Volume 46 , Issue 4 , March 2016 , pp. 807 - 818
Copyright
Copyright © Cambridge University Press 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aas, M, Dazzan, P, Fisher, HL, Morgan, C, Morgan, K, Reichenberg, A, Zanelli, J, Fearon, P, Jones, PB, Murray, RM, Pariante, CM (2011). Childhood trauma and cognitive function in first-episode affective and non-affective psychosis. Schizophrenia Research 129, 12–19.CrossRefGoogle ScholarPubMed
Akiskal, KK, Akiskal, HS (2005). The theoretical underpinnings of affective temperaments: implications for evolutionary foundations of bipolar disorder and human nature. Journal of Affective Disorders 85, 231–239.CrossRefGoogle ScholarPubMed
Andreasen, NC, Flaum, M, Arndt, S (1992). The Comprehensive Assessment of Symptoms and History (CASH). An instrument for assessing diagnosis and psychopathology. Archives of General Psychiatry 49, 615–623.CrossRefGoogle ScholarPubMed
Apeldoorn, SY, Sterk, B, van den Heuvel, ER, Schoevers, RA, Islam, MA, Bruggeman, R, Cahn, W, de Haan, L, Kahn, RS, Meijer, CJ, Myin-Germeys, I, van Os, J, Wiersma, D (2014). Factors contributing to the duration of untreated psychosis. Schizophrenia Research 158, 76–81.CrossRefGoogle Scholar
Arts, B, Jabben, N, Krabbendam, L, van Os, J (2008). Meta-analyses of cognitive functioning in euthymic bipolar patients and their first-degree relatives. Psychological Medicine 38, 771–785.CrossRefGoogle ScholarPubMed
Balanza-Martinez, V, Rubio, C, Selva-Vera, G, Martinez-Aran, A, Sanchez-Moreno, J, Salazar-Fraile, J, Vieta, E, Tabares-Seisdedos, R (2008). Neurocognitive endophenotypes (endophenocognitypes) from studies of relatives of bipolar disorder subjects: a systematic review. Neuroscience Biobehavioral Reviews 32, 1426–1438.CrossRefGoogle ScholarPubMed
Barro, RJ, Lee, JW (2013). A new data set of educational attainment in the world, 1950–2010. Journal of Development Economics 104, 184–198.CrossRefGoogle Scholar
Blyler, CR, Gold, JM, Iannone, VN, Buchanan, RW (2000). Short form of the WAIS-III for use with patients with schizophrenia. Schizophrenia Research 46, 209–215.CrossRefGoogle ScholarPubMed
Bora, E, Pantelis, C (2015). Meta-analysis of cognitive impairment in first-episode bipolar disorder: comparison with first-episode schizophrenia and healthy controls. Schizophrenia Bulletin 41, 1095–1104.CrossRefGoogle ScholarPubMed
Bora, E, Yucel, M, Pantelis, C (2009). Cognitive endophenotypes of bipolar disorder: a meta-analysis of neuropsychological deficits in euthymic patients and their first-degree relatives. Journal of Affective Disorders 113, 1–20.CrossRefGoogle ScholarPubMed
Cannon, TD, Huttunen, MO, Lonnqvist, J, Tuulio-Henriksson, A, Pirkola, T, Glahn, D, Finkelstein, J, Hietanen, M, Kaprio, J, Koskenvuo, M (2000). The inheritance of neuropsychological dysfunction in twins discordant for schizophrenia. The American Journal of Human Genetics 67, 369–382.CrossRefGoogle ScholarPubMed
Chamorro-Premuzic, T, Furnham, A (2003). Personality predicts academic performance: evidence from two longitudinal university samples. Journal of Research in Personality 37, 319–338.CrossRefGoogle Scholar
Coffman, JA, Bornstein, RA, Olson, SC, Schwarzkopf, SB, Nasrallah, HA (1990). Cognitive impairment and cerebral structure by MRI in bipolar disorder. Biological Psychiatry 27, 1188–1196.CrossRefGoogle ScholarPubMed
Davies, G, Tenesa, A, Payton, A, Yang, J, Harris, SE, Liewald, D, Ke, X, Le Hellard, S, Christoforou, A, Luciano, M, McGhee, K, Lopez, L, Gow, AJ, Corley, J, Redmond, P, Fox, HC, Haggarty, P, Whalley, LJ, McNeill, G, Goddard, ME, Espeseth, T, Lundervold, AJ, Reinvang, I, Pickles, A, Steen, VM, Ollier, W, Porteous, DJ, Horan, M, Starr, JM, Pendleton, N, Visscher, PM, Deary, IJ (2011). Genome-wide association studies establish that human intelligence is highly heritable and polygenic. Molecular Psychiatry 16, 996–1005.CrossRefGoogle ScholarPubMed
Deary, IJ, Penke, L, Johnson, W (2010). The neuroscience of human intelligence differences. Nature Reviews Neuroscience 11, 201–211.CrossRefGoogle ScholarPubMed
Deary, IJ, Strand, S, Smith, P, Fernandes, C (2007). Intelligence and educational achievement. Intelligence 35, 13–21.CrossRefGoogle Scholar
Dickson, H, Laurens, KR, Cullen, AE, Hodgins, S (2012). Meta-analyses of cognitive and motor function in youth aged 16 years and younger who subsequently develop schizophrenia. Psychological Medicine 42, 743–755.CrossRefGoogle ScholarPubMed
Egeland, JA, Hostetter, AM, Pauls, DL, Sussex, JN (2000). Prodromal symptoms before onset of manic-depressive disorder suggested by first hospital admission histories. Journal of the American Academy of Child and Adolescent Psychiatry 39, 1245–1252.CrossRefGoogle ScholarPubMed
Elvevag, B, Goldberg, TE (2000). Cognitive impairment in schizophrenia is the core of the disorder. Critical Reviews in Neurobiology 14, 1–21.CrossRefGoogle ScholarPubMed
Eric, YW, Halari, R, Cheng, KM, Leung, SK, Young, AH (2013). Cognitive performance is impaired in euthymic Chinese patients with Bipolar 1 Disorder. Journal of Affective Disorders 151, 156–163.CrossRefGoogle ScholarPubMed
First, MB, Spitzer, RL, Gibbon, M, Williams, JBW (1997). Structured Clinical Interview for DSM-IV Axis I Disorders (SCID I). Biometric Research Department: New York.Google Scholar
Frangou, S, Haldane, M, Roddy, D, Kumari, V (2005). Evidence for deficit in tasks of ventral, but not dorsal, prefrontal executive function as an endophenotypic marker for bipolar disorder. Biological Psychiatry 58, 838–839.CrossRefGoogle Scholar
Frantom, LV, Allen, DN, Cross, CL (2008). Neurocognitive endophenotypes for bipolar disorder. Bipolar Disorders 10, 387–399.CrossRefGoogle ScholarPubMed
Gale, CR, Batty, GD, McIntosh, AM, Porteous, DJ, Deary, IJ, Rasmussen, F (2013). Is bipolar disorder more common in highly intelligent people? A cohort study of a million men. Molecular Psychiatry 18, 190–194.CrossRefGoogle ScholarPubMed
Hughes, C, Kumari, V, Das, M, Zachariah, E, Ettinger, U, Sumich, A, Sharma, T (2005). Cognitive functioning in siblings discordant for schizophrenia. Acta Psychiatrica. Scandinavica 111, 185–192.CrossRefGoogle ScholarPubMed
Kahn, RS, Keefe, RS (2013). Schizophrenia is a cognitive illness: time for a change in focus. JAMA Psychiatry 70, 1107–1112.CrossRefGoogle ScholarPubMed
Korver, N, Quee, PJ, Boos, HB, Simons, CJ, de Haan, L (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, 205–221.CrossRefGoogle Scholar
Kremen, WS, Faraone, SV, Seidman, LJ, Pepple, JR, Tsuang, MT (1998). Neuropsychological risk indicators for schizophrenia: a preliminary study of female relatives of schizophrenic and bipolar probands. Psychiatry Research 79, 227–240.CrossRefGoogle ScholarPubMed
Leverich, GS, Nolen, WA, Rush, AJ, McElroy, SL, Keck, PE, Denicoff, KD, Suppes, T, Altshuler, LL, Kupka, R, Kramlinger, KG, Post, RM (2001). The Stanley Foundation Bipolar Treatment Outcome Network. I. Longitudinal methodology. Journal of Affective Disorders 67, 33–44.CrossRefGoogle Scholar
MacCabe, JH (2008). Population-based cohort studies on premorbid cognitive function in schizophrenia. Epidemiologic Reviews 30, 77–83.CrossRefGoogle ScholarPubMed
MacCabe, JH, Lambe, MP, Cnattingius, S, Sham, PC, David, AS, Reichenberg, A, Murray, RM, Hultman, CM (2010). Excellent school performance at age 16 and risk of adult bipolar disorder: national cohort study. British Journal of Psychiatry 196, 109–115.CrossRefGoogle ScholarPubMed
MacCabe, JH, Lambe, MP, Cnattingius, S, Torrang, A, Bjork, C, Sham, PC, David, AS, Murray, RM, Hultman, CM (2008). Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study. Psychological Medicine 38, 1133–1140.CrossRefGoogle ScholarPubMed
Mann-Wrobel, MC, Carreno, JT, Dickinson, D (2011). Meta-analysis of neuropsychological functioning in euthymic bipolar disorder: an update and investigation of moderator variables. Bipolar Disorders 13, 334–342.CrossRefGoogle ScholarPubMed
Martinez-Aran, A, Vieta, E, Reinares, M, Colom, F, Torrent, C, Sanchez-Moreno, J, Benabarre, A, Goikolea, JM, Comes, M, Salamero, M (2004). Cognitive function across manic or hypomanic, depressed, and euthymic states in bipolar disorder. American Journal of Psychiatry 161, 262–270.CrossRefGoogle ScholarPubMed
Maxwell, ME (1992). Family Interview for Genetic Studies (FIGS): A Manual for FIGS. NIMH: Clinical Neurogenetics Branch: Bethesda, MD.Google Scholar
McClellan, J, Prezbindowski, A, Breiger, D, McCurry, C (2004). Neuropsychological functioning in early onset psychotic disorders. Schizophrenia Research 68, 21–26.CrossRefGoogle ScholarPubMed
McIntosh, AM, Gow, A, Luciano, M, Davies, G, Liewald, DC, Harris, SE, Corley, J, Hall, J, Starr, JM, Porteous, DJ, Tenesa, A, Visscher, PM, Deary, IJ (2013). Polygenic risk for schizophrenia is associated with cognitive change between childhood and old age. Biological Psychiatry 15, 938–943.CrossRefGoogle Scholar
McIntosh, AM, Harrison, LK, Forrester, K, Lawrie, SM, Johnstone, EC (2005). Neuropsychological impairments in people with schizophrenia or bipolar disorder and their unaffected relatives. British Journal of Psychiatry 186, 378–385.CrossRefGoogle ScholarPubMed
Pachet, AK, Wisniewski, AM (2003). The effects of lithium on cognition: an updated review. Psychopharmacology (Berlin) 170, 225–234.CrossRefGoogle ScholarPubMed
Pirkola, T, Tuulio-Henriksson, A, Glahn, D, Kieseppa, T, Haukka, J, Kaprio, J, Lonnqvist, J, Cannon, TD (2005). Spatial working memory function in twins with schizophrenia and bipolar disorder. Biological Psychiatry 58, 930–936.CrossRefGoogle ScholarPubMed
Psychiatric GWAS Consortium Bipolar Disorder Working Group (2011). Large-scale genome-wide association analysis of bipolar disorder identifies a new susceptibility locus near ODZ4. Nature Genetics 43, 977–983.CrossRefGoogle Scholar
Purcell, SM, Wray, NR, Stone, JL, Visscher, PM, O'Donovan, MC, Sullivan, PF, Sklar, P (2009). Common polygenic variation contributes to risk of schizophrenia and bipolar disorder. Nature 460, 748–752.Google ScholarPubMed
R Core Team (2014). R: A language and environment for statistical computing, Vienna, Austria (http://www.R-project.org/).Google Scholar
Regeer, EJ, Krabbendam, L, De Graaf, R, Have, MT, Nolen, WA, van Os, J (2009). Berkson's bias and the mood dimensions of bipolar disorder. International Journal of Methods in Psychiatric Research 18, 279–286.CrossRefGoogle ScholarPubMed
Reichenberg, A, Harvey, PD, Bowie, CR, Mojtabai, R, Rabinowitz, J, Heaton, RK, Bromet, E (2009). Neuropsychological function and dysfunction in schizophrenia and psychotic affective disorders. Schizophrenia Bulletin 35, 1022–1029.CrossRefGoogle ScholarPubMed
Reichenberg, A, Weiser, M, Rabinowitz, J, Caspi, A, Schmeidler, J, Mark, M, Kaplan, Z, Davidson, M (2002). A population-based cohort study of premorbid intellectual, language, and behavioral functioning in patients with schizophrenia, schizoaffective disorder, and nonpsychotic bipolar disorder. American Journal of Psychiatry 159, 2027–2035.CrossRefGoogle ScholarPubMed
Robinson, LJ, Ferrier, IN (2006). Evolution of cognitive impairment in bipolar disorder: a systematic review of cross-sectional evidence. Bipolar Disorders 8, 103–116.CrossRefGoogle ScholarPubMed
Robinson, LJ, Thompson, JM, Gallagher, P, Goswami, U, Young, AH, Ferrier, IN, Moore, PB (2006). A meta-analysis of cognitive deficits in euthymic patients with bipolar disorder. Journal of Affective Disorders 93, 105–115.CrossRefGoogle ScholarPubMed
Sartorius, N, Gulbinat, W, Harrison, G, Laska, E, Siegel, C (1996). Long-term follow-up of schizophrenia in 16 countries. A description of the International Study of Schizophrenia conducted by the World Health Organization. Soc. Psychiatry. Psychiatr. Epidemiology 31, 249–258.CrossRefGoogle Scholar
Schizophrenia Psychiatric Genome-Wide Association Study (GWAS) Consortium (2011). Genome-wide association study identifies five new schizophrenia loci. Nature Genetics 43, 969–976.CrossRefGoogle Scholar
Schubart, CD, van Gastel, WA, Breetvelt, EJ, Beetz, SL, Ophoff, RA, Sommer, IE, Kahn, RS, Boks, MP (2011). Cannabis use at a young age is associated with psychotic experiences. Psychological Medicine 41, 1301–1310.CrossRefGoogle Scholar
Senturk, V, Goker, C, Bilgic, A, Olmez, S, Tugcu, H, Oncu, B, Atbasoglu, EC (2007). Impaired verbal memory and otherwise spared cognition in remitted bipolar patients on monotherapy with lithium or valproate. Bipolar Disorders 9 (Suppl. 1), 136–144.CrossRefGoogle ScholarPubMed
Sheehan, DV, Lecrubier, Y, Sheehan, KH, Amorim, P, Janavs, J, Weiller, E, Hergueta, T, Baker, R, Dunbar, GC (1998). The Mini-International Neuropsychiatric Interview (M.I.N.I.): the development and validation of a structured diagnostic psychiatric interview for DSM-IV and ICD-10. Journal of Clinical Psychiatry 59(Suppl. 20), 22–33.Google ScholarPubMed
Suppes, T, Leverich, GS, Keck, PE, Nolen, WA, Denicoff, KD, Altshuler, LL, McElroy, SL, Rush, AJ, Kupka, R, Frye, MA, Bickel, M, Post, RM (2001). The Stanley Foundation Bipolar Treatment Outcome Network. II. Demographics and illness characteristics of the first 261 patients. Journal of Affective Disorders 67, 45–59.CrossRefGoogle ScholarPubMed
Torres, IJ, Boudreau, VG, Yatham, LN (2007). Neuropsychological functioning in euthymic bipolar disorder: a meta-analysis. Acta Psychiatrica Scandinavica (Suppl.) 116, 17–26.CrossRefGoogle Scholar
Toulopoulou, T, Quraishi, S, McDonald, C, Murray, RM (2006). The Maudsley Family Study: premorbid and current general intellectual function levels in familial bipolar I disorder and schizophrenia. Journal of Clinical and Experimental Neuropsychology 28, 243–259.CrossRefGoogle ScholarPubMed
Trotta, A, Murray, RM, MacCabe, JH (2015). Do premorbid and post-onset cognitive functioning differ between schizophrenia and bipolar disorder? A systematic review and meta-analysis. Psychological Medicine 45, 381–394.CrossRefGoogle ScholarPubMed
van Oel, CJ, Sitskoorn, MM, Cremer, MP, Kahn, RS (2002). School performance as a premorbid marker for schizophrenia: a twin study. Schizophrenia Bulletin 28, 401–414.CrossRefGoogle ScholarPubMed
Vinkers, CH, van Gastel, WA, Schubart, CD, Van Eijk, KR, Luykx, JJ, Van Winkel, R, Joels, M, Ophoff, RA, Boks, MP, Bruggeman, R, Cahn, W, De Haan, L, Kahn, RS, Meijer, CJ, Myin-Germeys, I, van Os, J, Wiersma, D (2013). The effect of childhood maltreatment and cannabis use on adult psychotic symptoms is modified by the COMT Val158Met polymorphism. Schizophrenia Research 150, 303–311.CrossRefGoogle ScholarPubMed
Vonk, R, van der Schot, AC, van Baal, GC, van Oel, CJ, Nolen, WA, Kahn, RS (2012). Premorbid school performance in twins concordant and discordant for bipolar disorder. Journal of Affective Disorders 136, 294–303.CrossRefGoogle ScholarPubMed
Vreeker, A, Van Bergen, AH, Kahn, RS (2015). Cognitive enhancing agents in schizophrenia and bipolar disorder. European Neuropsychopharmacology 25, 969–1002.CrossRefGoogle ScholarPubMed
Wechsler, D (1997). WAIS-III:Wechsler Adult Intelligence Scale, 3rd edn. Administration and Scoring Manual. Psychological Corporation/Harcourt Brace: San Antonio, TX.Google Scholar
Wing, JK, Babor, T, Brugha, T, Burke, J, Cooper, JE, Giel, R, Jablenski, A, Regier, D, Sartorius, N (1990). SCAN. Schedules for Clinical Assessment in Neuropsychiatry. Archives of General Psychiatry 47, 589–593.CrossRefGoogle ScholarPubMed
Wingo, AP, Wingo, TS, Harvey, PD, Baldessarini, RJ (2009). Effects of lithium on cognitive performance: a meta-analysis. Journal of Clinical Psychiatry 70, 1588–1597.CrossRefGoogle ScholarPubMed
Woodberry, KA, Giuliano, AJ, Seidman, LJ (2008). Premorbid IQ in schizophrenia: a meta-analytic review. American Journal of Psychiatry 165, 579–587.CrossRefGoogle ScholarPubMed
Zammit, S, Allebeck, P, David, AS, Dalman, C, Hemmingsson, T, Lundberg, I, Lewis, G (2004). A longitudinal study of premorbid IQ Score and risk of developing schizophrenia, bipolar disorder, severe depression, and other nonaffective psychoses. Archives of General Psychiatry 61, 354–360.CrossRefGoogle ScholarPubMed
Supplementary material: File

Vreeker supplementary material

Tables S1-S4 and Figure S1

Download Vreeker supplementary material(File)
File 39 KB