A Longitudinal Study of Premorbid IQ Score and Risk of Developing Schizophrenia,Bipolar Disorder, Severe Depression, and Other Nonaffective Psychoses

Zammit, Stanley; Allebeck, Peter; David, Anthony S.; Dalman, Christina; Hemmingsson, Tomas; Lundberg, Ingvar; Lewis, Glyn

doi:10.1001/archpsyc.61.4.354

Cited by 421 publications

(363 citation statements)

References 34 publications

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“…Such nonadherence to medical regimens is likely to lead to increased mortality rates (9). Higher childhood intelligence is associated with reduced rates of major psychiatric disease, such as psychosis and depression (60)(61)(62). If real, at least two plausible explanations exist for this relation.…”

Section: Iq and Later Mortality Riskmentioning

confidence: 99%

Premorbid (early life) IQ and Later Mortality Risk: Systematic Review

Batty

Deary

Gottfredson³

2007

Annals of Epidemiology

418

343

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PURPOSE: Studies of middle-aged and particularly older-aged adults found that those with higher scores on tests of IQ (cognitive function) had lower rates of later mortality. Interpretation of such findings potentially is hampered by the problem of reverse causality: such somatic diseases as diabetes or hypertension, common in older adults, can decrease cognitive function. Studies that provide extended follow-up of the health experience of individuals who had their (premorbid) IQ assessed in childhood and/or early adulthood minimize this concern. The purpose of the present report is to systematically locate, evaluate, and interpret the findings of all such studies. METHODS: We systematically identified individual-level studies linking premorbid IQ with later mortality by using four approaches: search of electronic databases (MEDLINE, EMBASE, and PSYCHINFO); scrutiny of the reference sections of identified reports; search of our own files; and contact with researchers in the field. Study quality was assessed by using predefined criteria. RESULTS: Nine cohort studies met the inclusion criteria. Overall, study quality was moderate. All reports showed an inverse IQ-mortality relation; i.e., higher IQ scores were associated with decreased mortality risk. The nature of this relation (i.e., dose-response or threshold) and whether it differs by sex was unclear. The IQ-mortality association did not appear to be explained by reverse causality or selection bias. Confounding by other early-life factors also did not seem to explain the association, although some studies were not well characterized in this regard. Adult socioeconomic position appeared to mediate the IQ-mortality association in some studies, but this was not a universal finding. CONCLUSIONS: In all studies, higher IQ in the first two decades of life was related to lower rates of total mortality in middle to late adulthood. Some plausible mechanistic pathways exist, but further examination is required. The precise nature of the IQ-mortality relation (particularly in ethnic minorities and women) and the link between IQ and disease-specific outcomes also warrants further research. Ann Epidemiol -;-:-. Ó

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Section: Iq and Later Mortality Riskmentioning

confidence: 99%

Premorbid (early life) IQ and Later Mortality Risk: Systematic Review

Batty

Deary

Gottfredson³

2007

Annals of Epidemiology

418

343

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“…Several prospective studies have examined intellectual function in pre-schizophrenic children or adolescents using prospectively ascertained neuropsychological batteries (Jones & Done, 1997 ;Davidson et al 1999 ;Cannon et al 2000 ;Reichenberg et al 2002 ;Zammit et al 2004). The results of these studies, using a variety of designs, are notable for their consistency in demonstrating that schizophrenia is associated with global pre-morbid cognitive abnormalities.…”

Section: Introductionmentioning

confidence: 99%

Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study

et al. 2007

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Background. There is abundant evidence that schizophrenia is associated with cognitive deficits in childhood. However, previous studies investigating school performance have been inconclusive. Furthermore, there are several biological and social factors that could confound the association. We investigated whether school performance at age 16 is associated with risk of adult schizophrenia and other psychoses in a large national cohort, while controlling for multiple confounders.Method. Using a national sample of 907 011 individuals born in Sweden between 1973 and 1983, we used Cox regression to assess whether scholastic achievement at age 15-16 predicted hospital admission for psychosis between ages 17 and 31, adjusting for potential confounders.Results. Poor school performance was associated with increased rates of schizophrenia [hazard ratio (HR) 3.9, 95 % confidence interval (CI) 2.8-5.3], schizo-affective disorder (HR 4.2, 95 % CI 1.9-9.1) and other psychoses (HR 3.0, 95 % CI 2.3-4.0). Receiving the lowest (E) grade was significantly associated with risk for schizophrenia and other psychoses in every school subject. There was no evidence of confounding by migrant status, low birthweight, hypoxia, parental education level or socio-economic group.Conclusions. Poor school performance across all domains is strongly associated with risk for schizophrenia and other psychoses.

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“…Mental retardation was found in 17 of the subjects and they exhibited significantly more manic episodes than mixed ones. In a follow-up study examining an 18 to 20-year-old conscripted male cohort, low premorbid IQ was associated with increased risk of schizophrenia but not with BD [58]. To our knowledge, there is no other study on acute mania phenomenology in adolescents with MR.…”

Section: Discussion J Limitations and Strengthsmentioning

confidence: 92%

Phenomenology, socio-demographic factors and outcome upon discharge of manic and mixed episodes in hospitalized adolescents

Brunelle

Consoli

Tanguy

et al. 2009

Eur Child Adolesc Psychiatry

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Med J 29, 2006). Little is known on the phenomenology and potential short-term prognosis factors of bipolar episodes in this age population. In particular, very few studies examine this issue on inpatients in the European context of free access to care. Objective To describe the phenomenology of acute manic and mixed episodes in hospitalized adolescents and to analyse potential predictive factors associated with clinical improvement at discharge and length of hospitalization. Methods A total of 80 subjects, aged 12-20 years, consecutively hospitalized for a manic or mixed episode. Sociodemographic and clinical data were extracted by reviewing patients' charts. We used a multivariate analysis to evaluate shortterm outcome predictors. Results The sample was characterized by severe impairment, high rates of psychotic features (N = 50, 62.5%), a long duration of stay (mean 80.4 days), and an overall good improvement (86% very much or much improved). Thirtythree (41.3 %) patients had a history of depressive episodes, 13 (16.3%) had manic or brief psychotic episodes but only 3 (3.7%) had a history of attention deficit/ hyperactivity disorders. More manic episodes than mixed episodes were identified in subjects with mental retardation (MR) and in subjects from migrant and/or low socio-economic families. Overall severity and female gender predicted better improvement in GAF scores. Poor insight and the existence of psychotic features predicted longer duration of stay. Conclusion These results suggest that severe manic and mixed episodes in adolescents with BD-I need prolonged inpatient care to improve and that socio-cultural factors and MR should be examined more closely in youth with BD.j Key words bipolar disorder type I -acute episodeadolescent -prognosissocio-cultural factors BRIEF REPORT

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A Longitudinal Study of Premorbid IQ Score and Risk of Developing Schizophrenia,Bipolar Disorder, Severe Depression, and Other Nonaffective Psychoses

Cited by 421 publications

References 34 publications

Premorbid (early life) IQ and Later Mortality Risk: Systematic Review

Premorbid (early life) IQ and Later Mortality Risk: Systematic Review

Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study

Phenomenology, socio-demographic factors and outcome upon discharge of manic and mixed episodes in hospitalized adolescents

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