TY - JOUR
T1 - Change in IQ in schizophrenia patients and their siblings
T2 - a controlled longitudinal study
AU - Van Haren, N. E. M.
AU - Van Dam, D. S.
AU - Stellato, R. K.
AU - Alizadeh, Behrooz Z.
AU - van Amelsvoort, Therese
AU - Bartels-Velthuis, Agna A.
AU - van Beveren, Nico J.
AU - Bruggeman, Richard
AU - Cahn, Wiepke
AU - de Haan, Lieuwe
AU - Delespaul, Philippe
AU - Meijer, Carin J.
AU - Myin-Germeys, Inez
AU - Kahn, Rene S.
AU - Schirmbeck, Frederike
AU - Simons, Claudia J. P.
AU - van Os, Jim
AU - van Winkel, Ruud
AU - Luykx, Jurjen J.
AU - Genetic Risk and Outcome of Psychosis (GROUP) Investigators
N1 - Funding Information:
We thank the Geestkracht programme of the Dutch Health Research Council (ZonMw, grant number 10-000-1001) for funding the infrastructure for the GROUP study, and participating pharmaceutical companies (Lundbeck, AstraZeneca, Eli Lilly, and Janssen Cilag) and universities and mental health care organizations (Amsterdam: Academic Psychiatric Centre of the Academic Medical Center and the mental health institutions: GGZ Ingeest, Arkin, Dijk en Duin, GGZ Rivierduinen, Erasmus Medical Centre, GGZ Noord Holland Noord. Groningen: University Medical Center Groningen and the mental health institutions: Lentis, GGZ Friesland, GGZ Drenthe, Dimence, Mediant, GGNet Warnsveld, Yulius Dordrecht and Parnassia psycho-medical center The Hague. Maastricht: Maastricht University Medical Centre and the mental health institutions: GGZ Eindhoven en De Kempen, GGZ Breburg, GGZ Oost-Brabant, Vincent van Gogh voor Geestelijke Gezondheid, Mondriaan, Virenze riagg, Zuyderland GGZ, MET ggz, Universitair Centrum Sint-Jozef Kortenberg, CAPRI University of Antwerp, PC Ziekeren Sint-Truiden, PZ Sancta Maria Sint-Truiden, GGZ Overpelt, OPZ Rekem. Utrecht: University Medical Center Utrecht and the mental health institutions Altrecht, GGZ Centraal and Delta) for matching funds. This paper has been presented at the SIRS meeting 14-18 April 2012, Florence, Italy, and at the ICOSR meeting 21-25 April 2013, Orlando, Florida, USA.
Publisher Copyright:
Copyright © Cambridge University Press 2019.
PY - 2019/11
Y1 - 2019/11
N2 - Background. 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.Methods. 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).Results. 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 (+03 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.Conclusions. 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.
AB - Background. 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.Methods. 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).Results. 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 (+03 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.Conclusions. 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.
KW - Intelligence
KW - longitudinal
KW - outcome
KW - schizophrenia
KW - siblings
KW - 1ST EPISODE PSYCHOSIS
KW - 1ST-EPISODE SCHIZOPHRENIA
KW - COGNITIVE-DEVELOPMENT
KW - RISK
KW - INTELLIGENCE
KW - ONSET
KW - NEUROCOGNITION
KW - METAANALYSIS
KW - PERFORMANCE
KW - DECLINE
U2 - 10.1017/S0033291718003537
DO - 10.1017/S0033291718003537
M3 - Article
C2 - 30674361
SN - 0033-2917
VL - 49
SP - 2573
EP - 2581
JO - Psychological Medicine
JF - Psychological Medicine
IS - 15
ER -