Intellectual Decline in Schizophrenia: Evidence from a Prospective Birth Cohort 28 Year Follow-up Study

Department of Psychiatry at Massachusetts Mental Health Center, Harvard Medical School, Boston, USA.
Journal of Clinical and Experimental Neuropsychology (Impact Factor: 2.08). 03/2006; 28(2):225-42. DOI: 10.1080/13803390500360471
Source: PubMed


It is well established that IQ is lower among persons with schizophrenia than in the general population. However, it remains unclear if there is deterioration beyond a premorbid deficit. In order to assess the question of IQ deterioration, we assessed persons pre- and-post psychosis, comparing those who developed schizophrenia with those who did not. Twenty six patients with schizophrenia and 59 normal controls, evaluated at age 7 in the prospective, longitudinal, National Collaborative Perinatal Project (NCPP), were re-tested approximately 28 years later. We assessed change in an estimate of IQ based on the Vocabulary and Block Design tests from the Wechsler intelligence scales. Persons who later developed schizophrenia were significantly impaired on IQ compared to controls at age 7, especially on measures of attention. At age 35, persons with schizophrenia demonstrated significant impairment and deterioration on both IQ sub-tests compared to controls. Because impairment occurs by early childhood and subsequent deterioration occurs at an unknown period, designs with more frequent assessment of IQ through the premorbid, prodromal and early phases of illness are required to identify the key period of decline. Future research on this sample will evaluate the prospective roles of family history and perinatal complications on cognition, and assess the specificity of these findings.

8 Reads
  • Source
    • "In previous studies, both education and IQ have been found to be significant protective factors and non-significant protective factors against psychotic symptoms (Wiles et al., 2006; Johns and van Os, 2001; Kelleher and Cannon, 2011). The association may also be explained by neurocognitive difficulties that are characteristic of psychosis, which may put individuals at greater risk of experiencing psychosis and discontinuing formal education (Niendam et al., 2003; Seidman et al., 2006). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent epidemiological evidence suggests that sub-threshold psychotic experiences commonly occur in the general population. When these experiences persist over time, they may increase risk for psychotic disorder or lead to other clinical or functional impairments. The aims of this study were to distinguish the relative importance of sociodemographic factors and clinical factors, including characteristics of the psychotic experiences themselves, in determining the course of psychotic symptoms over time. Participants were drawn from the Collaborative Psychiatric Epidemiology Surveys. We tested for retrospectively-reported predictors of current psychotic experiences among individuals who reported lifetime psychotic experiences, with onset prior to the past year (n=921), using logistic regression. Persistence was primarily related to demographic variables, with lower odds associated with being married and having at least a college education. Individuals reporting prior to the past year auditory hallucinations were more likely to have persistent psychotic experiences than those reporting other types of psychotic experiences. Interventions aiming at strengthening family support and social skills may reduce the likelihood of persistence among individuals with psychotic experiences, thereby reducing risk for psychotic disorders and other related outcomes. Future studies should continue to identify predictors of persistence versus remission and further explore clinical services for those with persistent psychotic experiences.
    Schizophrenia Research 09/2015; DOI:10.1016/j.schres.2015.08.039 · 3.92 Impact Factor
  • Source
    • "When cognitive deficits are first present and whether there is some stage of the illness during which they progress have been areas of intensive study.98,99 Cognitive deficits have been clearly demonstrated at the time of the FEP.89,98,100 "
    [Show abstract] [Hide abstract]
    ABSTRACT: Schizophrenia has historically been considered to be a deteriorating disease, a view reinforced by recent MRI findings of progressive brain tissue loss over the early years of illness. On the other hand, the notion that recovery from schizophrenia is possible is increasingly embraced by consumer and family groups. This review critically examines the evidence from longitudinal studies of (1) clinical outcomes, (2) MRI brain volumes, and (3) cognitive functioning. First, the evidence shows that although approximately 25% of people with schizophrenia have a poor long-term outcome, few of these show the incremental loss of function that is characteristic of neurodegenerative illnesses. Second, MRI studies demonstrate subtle developmental abnormalities at first onset of psychosis and then further decreases in brain tissue volumes; however, these latter decreases are explicable by the effects of antipsychotic medication, substance abuse, and other secondary factors. Third, while patients do show cognitive deficits compared with controls, cognitive functioning does not appear to deteriorate over time. The majority of people with schizophrenia have the potential to achieve long-term remission and functional recovery. The fact that some experience deterioration in functioning over time may reflect poor access, or adherence, to treatment, the effects of concurrent conditions, and social and financial impoverishment. Mental health professionals need to join with patients and their families in understanding that schizophrenia is not a malignant disease that inevitably deteriorates over time but rather one from which most people can achieve a substantial degree of recovery.
    Schizophrenia Bulletin 11/2012; 39(6). DOI:10.1093/schbul/sbs135 · 8.45 Impact Factor
  • Source
    • "Seidman and colleagues examined changes in IQ of persons with schizophrenia when they were aged 7 years-old and again about 28 years later in Seidman and colleagues examined changes in IQ of person with schizophrenia when they were 7 years-old and again about 28 years later. The researchers showed that persons who developed schizophrenia had lower QI scores when tested as children relatively to non-schizophrenic peers; moreover, schizophrenic patients showed decline of, on average, 10 QI points [138]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We discuss recent evidences about schizophrenia (frequency, onset, course, risk factors and genetics) and their influences to some epidemiological myths about schizophrenia diffuse between psychiatric and psychopathology clinicians. The scope is to evaluate if the new acquisitions may change the rehabilitation approaches to schizophrenia modifying the balance about the neurodevelopmental hypothesis of schizophrenia accepting that the cognitive deficits are produced by errors during the normal development of the brain (neurodevelopmental hypothesis) that remains stable in the course of illness and the neurodegenerative hypothesis according of which they derived from a degenerative process that goes on inexorably. RESEARCH METHOD/DESIGN: A review of the literature about epidemiology of schizophrenia has been performed and the contributions of some of these evidence to neurodevelopmental hypothesis and to rehabilitation has been described. It cannot be definitively concluded for or against the neurodevelopmental or degenerative hypothesis, but efforts in understanding basis of schizophrenia must go on. Until now, rehabilitation programs are based on the vulnerability-stress model: supposing an early deficit that go on stable during the life under favorable circumstances. So, rehabilitation approaches (as neuro-cognitive approaches, social skill training, cognitive-emotional training) are focused on the individual and micro-group coping skills, aiming to help people with schizophrenia to cope with environmental stress factors. Coping of cognitive deficits in schizophrenia may represents the starting-point for further research on schizophrenia, cohort studies and randomized trials are necessary to defined the range of effectiveness and the outcome of the treatments.
    Clinical Practice and Epidemiology in Mental Health 07/2012; 8:52-66. DOI:10.2174/1745017901208010052
Show more