Mitochondrial DNA mutations and cognition: a case-series report.

Mutations in the mitochondrial genome can impair normal metabolic function in the central nervous system (CNS) where cellular energy demand is high. Primary mitochondrial DNA (mtDNA) mutations have been linked to several mitochondrial disorders that have comorbid psychiatric, neurologic, and cognitive sequelae. Here, we present a series of cases with primary mtDNA mutations who were genotyped and evaluated across a common neuropsychological battery. Nineteen patients with mtDNA mutations were genotyped and clinically and cognitively evaluated. Pronounced deficits in nonverbal/visuoperceptual reasoning, verbal recall, semantic word generativity, and processing speed were evident and consistent with a "mitochondrial dementia" that has been posited. However, variation in cognitive performance was noteworthy, suggesting that the phenotypic landscape of cognition linked to primary mtDNA mutations is heterogeneous. Our patients with mtDNA mutations evidenced cognitive deficits quite similar to those commonly seen in Alzheimer's disease and could have clinical relevance to the evaluation of dementia.

Neuropsychological and symptom predictors of aggression on the psychiatric inpatient service.

Neuropsychological assessment of executive dysfunction may identify psychiatric patients who may be at high risk for aggressive behavior because impairment of the prefrontal cortex has been indicated as a possible anatomical correlate of aggression. No consensus, however, has been reached on the extent that executive dysfunction contributes to the formation of psychopathology and to aggressive behavior in psychiatric inpatients. We hypothesized a mediating model wherein patients' executive-functioning deficits contribute to the formation of psychopathological symptoms, which then underlies aggressive behavior. To test this model, we examined the relationship between executive functioning, psychiatric symptomatology, and aggressive behavior in 85 psychiatric inpatients presenting over an acute hospital admission using structure equation modeling techniques. The results revealed that psychiatric inpatients' executive function impairment significantly predicted the formation of psychiatric symptomatology, which in turn significantly contributed to the manifestation of aggressive behavior. Executive dysfunction also directly predicted inpatient aggressive behavior. Combining the indirect and direct effects, 59% of our inpatient aggression measure factor variance was accounted for by our measures of executive dysfunction and clinical symptom severity. These findings suggest that neurocognitive deficits underlie both psychiatric symptom formation and aggression. Patients with executive dysfunction may not possess the behavioral inhibition skills needed to cope with the presence of symptoms and other stressful events that accompany acute psychosis and hospitalization that may result, consequently, in increased manifestations of aggressive behavior.

Predictors of aggression on the psychiatric inpatient service: self-esteem, narcissism, and theory of mind deficits.

Aggressive behavior committed by inpatients has significant negative effects on patients, clinical staff, the therapeutic milieu, and inpatient community as whole. Past research examining nonpsychiatric patient groups has suggested that elevated self-esteem and narcissism levels as well as self-serving theory of mind (ToM) biases may be robust predictors of aggressive behavior. In the present study, we examined whether these constructs were useful in predicting aggressive acts committed by psychiatric inpatients. Severity of psychiatric symptoms, demographic variables and patients' anger, and hostility severity were also examined. We found patients who committed acts of aggression were differentiated from their nonaggressive counterparts by exhibiting significantly higher levels of self-esteem and narcissistic superiority. In addition, aggressors demonstrated self-serving ToM biases, attributing more positive attributes to themselves, relative to their perceptions of how others viewed them. Aggressors also showed increased psychosis, fewer depressive symptoms, and had significantly fewer years of formal education than their nonaggressive peers. These results support and extend the view that in addition to clinical variables, specific personality traits and self-serving attributions are linked to aggressive behavior in acutely ill psychiatric patients.