title: Does cognitive impairment in treatment-resistant and ultra-treatment-resistant schizophrenia differ from that in treatment responders?
abstract: This study aimed to investigate whether cognitive impairment is more pronounced in people with treatment-resistant schizophrenia compared with those who respond well to first-line antipsychotic medication. Fifty-one patients with schizophrenia were assigned to one of three groups dependent on their clinical history: (i) 16 people who had responded well to first-line antipsychotic medication, (ii) 20 people who were treatment-resistant but responding to clozapine monotherapy, (iii) 15 people who were ultra-treatment-resistant/clozapine-resistant but responding to antipsychotic polypharmacy. Twenty-two controls were also recruited. Groups were matched for age, sex, disease duration and psychopathology. All participants undertook a computerised battery of neuropsychological tests that assessed multiple cognitive domains. Raw data were converted to z-scores, and test performance was compared between groups. People with schizophrenia performed significantly worse than controls in the majority of neuropsychological tests, with verbal memory, sustained attention, and sensorimotor the most commonly impaired domains. No significant differences in performance between people deemed to be treatment-resistant or ultra-treatment-resistant, and those who responded well to first-line antipsychotic medication were observed. There was no significant relationship between antipsychotic dose and scores on any of the neuropsychological tests. Cognitive impairment is a central feature of schizophrenia, but our results suggest that treatment-resistance may not be associated with more severe deficits.
authors.affiliation: School of Pharmacy, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Centre for Brain Research, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Valerie M
authors.initials: VM
authors.lastname: Anderson
authors.affiliation: School of Pharmacy, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Centre for Brain Research, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Meghan E
authors.initials: ME
authors.lastname: McIlwain
authors.affiliation: Centre for Brain Research, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Department of Psychological Medicine, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Kydd
authors.affiliation: School of Pharmacy, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Centre for Brain Research, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address: b.russell@auckland.ac.nz.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Russell
mesh_terms: D000293:Adolescent; D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001288:Attention; D016022:Case-Control Studies; D003024:Clozapine / Q000627:therapeutic use*; D003072:Cognition Disorders / Q000523:psychology*; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D011599:Psychopathology; D012559:Schizophrenia / Q000188:drug therapy*; D012565:Schizophrenic Psychology; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D003024:Clozapine
keywords: Clozapine; Cognition; Memory; Schizophrenia; Treatment-resistant