ABSTRACT
CONTEXT The single-nucleotide polymorphism rs1344706 in the gene ZNF804a has been associated with schizophrenia and with quantitative phenotypic features, including brain structure volume and the core symptoms of schizophrenia. OBJECTIVE To evaluate associations of rs1344706 with brain structure and the core symptoms of schizophrenia. DESIGN Case-control analysis of covariance. SETTING University-based research hospital. PARTICIPANTS Volunteer sample of 335 individuals with schizophrenia spectrum disorders (306 with core schizophrenia) and 198 healthy volunteers. MAIN OUTCOME MEASURES Cerebral cortical gray matter and white matter (WM) volumes (total and frontal, parietal, temporal, and occipital lobes), lateral ventricular cerebrospinal fluid volume, and symptom severity from the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms divided into 3 domains: psychotic, negative, and disorganized. RESULTS The rs1344706 genotype produced significant main effects on total, frontal, and parietal lobe WM volumes (F = 3.98, P = .02; F = 4.95, P = .007; and F = 3.08, P = .05, respectively). In the schizophrenia group, rs1344706 produced significant simple effects on total (F = 3.93, P = .02) and frontal WM volumes (F = 7.16, P < .001) and on psychotic symptom severity (F = 6.07, P = .003); the pattern of effects was concordant with risk allele carriers having larger volumes and more severe symptoms of disease than nonrisk homozygotes. In the healthy volunteer group, risk allele homozygotes had increased total WM volume compared with nonrisk allele carriers (F = 4.61, P = .03), replicating a previously reported association. CONCLUSIONS A growing body of evidence suggests that the risk allele of rs1347706 is associated with a distinctive set of phenotypic features in healthy volunteers and individuals with schizophrenia. Our study supports this assertion by finding that specific genotypes of the polymorphism are associated with brain structure volumes in individuals with schizophrenia and healthy volunteers and with symptom severity in schizophrenia.
Subject(s)
Alleles , Kruppel-Like Transcription Factors/genetics , Polymorphism, Single Nucleotide/genetics , Schizophrenia/genetics , Schizophrenic Psychology , Adult , Case-Control Studies , Cerebral Cortex/pathology , Female , Gene Frequency/genetics , Genetic Carrier Screening , Genetic Predisposition to Disease/genetics , Genotype , Homozygote , Humans , Image Interpretation, Computer-Assisted , Magnetic Resonance Imaging , Male , Organ Size/physiology , Phenotype , Psychiatric Status Rating Scales , Reference Values , Schizophrenia/diagnosis , Young AdultABSTRACT
OBJECTIVE: The authors' goal was to determine whether people with schizophrenia experience changes in decisional capacity when their antipsychotic regimens are discontinued for research purposes. METHOD: Capacity for informed consent for research, neuropsychological performance, and psychiatric symptoms were assessed before and after discontinuation of antipsychotic medication in 10 individuals with schizophrenia. RESULTS: Overall, participants showed minimal change on most measures during the medication-free interval, although their reasoning ability declined significantly. All participants who demonstrated adequate understanding of study procedures at enrollment retained this capacity throughout the study. CONCLUSIONS: Participants in medication-free schizophrenia research do not show a major decline in decisional capacity. However, the apparent decline in reasoning ability found in this study is of concern and underscores the need for both additional research on this topic and the development of remediational interventions aimed at enhancing this aspect of decisional capacity.
Subject(s)
Informed Consent/standards , Mental Competency/standards , Research Subjects/psychology , Schizophrenia , Adult , Antipsychotic Agents/therapeutic use , Cognition Disorders/diagnosis , Cognition Disorders/psychology , Decision Making , Female , Humans , Male , Neuropsychological Tests/standards , Patient Selection , Psychiatric Status Rating Scales , Schizophrenia/diagnosis , Schizophrenia/drug therapy , Schizophrenic PsychologyABSTRACT
OBJECTIVE: The degree to which people with psychiatric symptoms and cognitive dysfunction can provide informed consent to participate in research is a controversial issue. This study was designed to examine the capacity of subjects with schizophrenia and subjects with HIV to provide informed consent for research participation and to determine the relationships among cognitive dysfunction, psychiatric symptoms, and decisional capacity. METHOD: Twenty-five men and women with a DSM-IV diagnosis of schizophrenia and 25 men and women with HIV were recruited. The groups were compared in terms of neuropsychological functioning, psychiatric symptoms, and ability to provide informed consent to a hypothetical drug trial. RESULTS: Eighty percent of the subjects with schizophrenia and 96% of the HIV-positive subjects demonstrated adequate capacity to consent to the hypothetical drug trial, but subjects in the schizophrenia group had significantly lower scores on two of the four aspects of decisional capacity. For the subjects with schizophrenia, neuropsychological functioning and psychiatric symptoms (e.g., apathy and avolition), but not psychotic symptoms (e.g., hallucinations and delusions), were significantly associated with decisional capacity. CONCLUSIONS: The majority of subjects who are recruited and willing to participate in schizophrenia or HIV research will have adequate capacity to provide consent. Cognitive dysfunction and the symptoms shown to be associated with impaired decisional capacity are not unique to schizophrenia and may occur with many other forms of illness. These findings underscore the importance of considering how decisional capacity will be assessed in all types of research, regardless of the specific condition being studied.
