Neurocognitive deficits in schizophrenia. Are we making mountains out of molehills?

BACKGROUND

Most original studies and all meta-analyses conducted to date converge on the conclusion that patients with schizophrenia display rather generalized neurocognitive deficits. For the present study, we reopen this seemingly closed chapter and examine whether important influences, such as lack of motivation and negative attitudes towards cognitive assessment, result in poorer secondary neuropsychological performance.

METHOD

A sample of 50 patients with an established diagnosis of schizophrenia were tested for routine neurocognitive assessment and compared to 60 nonclinical volunteers. Before and after the assessment, subjective momentary influences were examined (e.g. motivation, concerns about assessment, fear about poor outcome) for their impact on performance using a new questionnaire called the Momentary Influences, Attitudes and Motivation Impact (MIAMI) on Cognitive Performance Scale.

RESULTS

As expected, patients performed significantly worse than controls on all neurocognitive domains tested (large effect size, on average). However, patients also displayed more subjective momentary impairment, as well as more fears about the outcome and less motivation than controls. Mediation analyses indicated that these influences contributed to (secondary) poorer neurocognitive performance. Differences in neurocognitive scores shrank to a medium effect size, on average, when MIAMI scores were accounted for.

CONCLUSIONS

The data argue that performance on measures of neurocognition in schizophrenia are to a considerable extent due to secondary factors. Poor motivation, fears and momentary impairments distinguished patients from controls and these variables heavily impacted performance. Before concluding that neurocognitive deficits in psychiatric patients are present, clinicians should take these confounding influences into account. Although patients with schizophrenia achieved, on average, worse test scores than controls, a large subgroup displayed spared performance.

Lack of nosocomial spread of Varicella in a pediatric hospital with negative pressure ventilated patient rooms

All patients at the new British Columbia's Children's Hospital with chickenpox or Herpes zoster are nursed with appropriate precautions in single-bed rooms provided with negative pressure ventilation. Over a period of 1 year, no nosocomial infections were detected on follow-up of 110 susceptible patients who had been on wards at the same time as six cases of chickenpox and one immunocompromised patient with cutaneous dissemination of Varicella zoster. In a preceding study at the previous hospital, with similar staff, control measures, and patient population, in an isolation facility without negative pressure ventilation, nosocomial infections occurred in seven out of 41 susceptible patients who were on the same ward as two patients with chickenpox. These findings suggest that a simple negative pressure ventilation system without air locks is a useful adjunct in the control of cutaneous Varicella infections.