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Neuropsychologically normal schizophrenia?
758
Abstracts /Archives
of Clinical Neuropsychologv
I.5 (2000) 653-850
treatment programs. A mixed race sample of 2554 males and 1214 females, all with histories of heroin use, were drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991- 1993 in 96 programs in 11 cities in the United States. The sample consisted of 1634 Caucasian subjects, 1547 African-American subjects and 587 Hispanic-American subjects. Data were analyzed to determine the effects of gender and ethnicity variables on the 2 parts of the TMT in this large sample of heroin abusers. Gender was statistically significantly related to performance on both TMT Parts A and B but the interaction of heroin use frequency and gender was not significant (P values, A=0.25, B =0.32). Ethnicity was statistically related to performance on both TMT Parts A and B, but the interaction of ethnicity and heroin use frequency was significant for Part A and only showed a trend for Part B (P values, A=0.02, B =0.07). R-Square values for overall models were quite weak (Gender/A= 0.009, B = 0.010, Ethnicity/A= 0.06, B = 0.06) suggesting that gender and ethnicity effects on the TMT are, while clearly present, account for little overall variance in terms of heroin use frequency. These results are consistent with earlier research using a more heterogenous drug abuse treatment sample.
Neuropsychologically
normal schizophrenia?
War-nick EL, Allan DN, Goldstein
G.
Because cognitive deficits commonly occur in schizophrenia, they are considered core features of the disorder. However, some patients with schizophrenia exhibit average to above average abilities, and appear to be neuropsychologically normal. If it is true that neuropsychologically normal patients with schizophrenia have no or relatively few cognitive deficits, then neurocognitive impairment cannot be considered a core feature of the disorder. This study addressed the issue of neuropsychologically normal schizophrenia by comparing a group of patients with schizophrenia who had ‘normal’ cognitive functioning, to a sample of patients with definitive evidence of structural brain damage, but who also performed in the normal range on neuropsychological tests. A non-schizophrenic, non-brain damaged sample (NC) was also included for comparison purposes. We hypothesized that the neuropsychologically normal schizophrenia group did have subtle but consistent cognitive deficits and so would exhibit a neuropsychological profile similar to the neuropsychologically normal brain damaged group, but unlike that of the NC group. To evaluate this hypothesis, the Halstead-Reitan Neuropsychological Test battery was administered to 113 patients with schizophrenia (SZ), 174 patients with brain damage (BD), and 106 non-braindamaged, non-schizophrenic hospital patients (NC). Subjects were classified as exhibiting normal or near-normal neuropsychological functioning based on the Halstead-Reitan Average Impairment Rating (AIR). Using an AIR cut off score of less than 1.60, 25% of the SZ group (SZ-NN) and 15% of the brain-damaged group (BD-NN) were classified as neuropsychologically normal. The SZ-NN, BD-NN and NC groups were similar on all demographic variables except age, which was used as a covariate in subsequent analyses. MANCOVA using group as the independent variable and the Halstead-Reitan test scores as the dependent variables indicated significant (pcO.01) differences between groups. Univariate F tests and contrasts that examined group differences consistently favored the patient comparison sample on all neuropsychological variables. However, there were also significant differences in patterns of performance between the SZ-NN and SZ-BD groups. These results are discussed in light of the current literature on neuropsychological functioning in schizophrenia.
Abstracts /Archives
of Clinical Neuropsychologv
I.5 (2000) 653-850
treatment programs. A mixed race sample of 2554 males and 1214 females, all with histories of heroin use, were drawn from electronic files of data from the Drug Abuse Treatment Outcome Study (DATOS). The DATOS was a naturalistic, prospective cohort study that collected data from 1991- 1993 in 96 programs in 11 cities in the United States. The sample consisted of 1634 Caucasian subjects, 1547 African-American subjects and 587 Hispanic-American subjects. Data were analyzed to determine the effects of gender and ethnicity variables on the 2 parts of the TMT in this large sample of heroin abusers. Gender was statistically significantly related to performance on both TMT Parts A and B but the interaction of heroin use frequency and gender was not significant (P values, A=0.25, B =0.32). Ethnicity was statistically related to performance on both TMT Parts A and B, but the interaction of ethnicity and heroin use frequency was significant for Part A and only showed a trend for Part B (P values, A=0.02, B =0.07). R-Square values for overall models were quite weak (Gender/A= 0.009, B = 0.010, Ethnicity/A= 0.06, B = 0.06) suggesting that gender and ethnicity effects on the TMT are, while clearly present, account for little overall variance in terms of heroin use frequency. These results are consistent with earlier research using a more heterogenous drug abuse treatment sample.
Neuropsychologically
normal schizophrenia?
War-nick EL, Allan DN, Goldstein
G.
Because cognitive deficits commonly occur in schizophrenia, they are considered core features of the disorder. However, some patients with schizophrenia exhibit average to above average abilities, and appear to be neuropsychologically normal. If it is true that neuropsychologically normal patients with schizophrenia have no or relatively few cognitive deficits, then neurocognitive impairment cannot be considered a core feature of the disorder. This study addressed the issue of neuropsychologically normal schizophrenia by comparing a group of patients with schizophrenia who had ‘normal’ cognitive functioning, to a sample of patients with definitive evidence of structural brain damage, but who also performed in the normal range on neuropsychological tests. A non-schizophrenic, non-brain damaged sample (NC) was also included for comparison purposes. We hypothesized that the neuropsychologically normal schizophrenia group did have subtle but consistent cognitive deficits and so would exhibit a neuropsychological profile similar to the neuropsychologically normal brain damaged group, but unlike that of the NC group. To evaluate this hypothesis, the Halstead-Reitan Neuropsychological Test battery was administered to 113 patients with schizophrenia (SZ), 174 patients with brain damage (BD), and 106 non-braindamaged, non-schizophrenic hospital patients (NC). Subjects were classified as exhibiting normal or near-normal neuropsychological functioning based on the Halstead-Reitan Average Impairment Rating (AIR). Using an AIR cut off score of less than 1.60, 25% of the SZ group (SZ-NN) and 15% of the brain-damaged group (BD-NN) were classified as neuropsychologically normal. The SZ-NN, BD-NN and NC groups were similar on all demographic variables except age, which was used as a covariate in subsequent analyses. MANCOVA using group as the independent variable and the Halstead-Reitan test scores as the dependent variables indicated significant (pcO.01) differences between groups. Univariate F tests and contrasts that examined group differences consistently favored the patient comparison sample on all neuropsychological variables. However, there were also significant differences in patterns of performance between the SZ-NN and SZ-BD groups. These results are discussed in light of the current literature on neuropsychological functioning in schizophrenia.