Heritability of functioning in families with schizophrenia in relation to neurocognition

The role of daily functioning is an integral part of the schizophrenia (SZ) phenotype and deficits in this trait appear to be present in both affected persons and some unaffected relatives; hence we have examined its heritability in our cohort of African American schizophrenia families. There is now ample evidence that deficits in cognitive function can impact family members who are not themselves diagnosed with SZ; there is some, but less evidence that role function behaves likewise. We evaluate whether role function tends to "run in families" who were ascertained because they contain an African American proband diagnosed with SZ.

METHODS

We analyzed heritability for selected traits related to daily function, employment, living situation, marital status, and Global Assessment Scale (GAS) score; modeling age, gender, along with neurocognition and diagnosis as covariates in a family based African-American sample (N=2488 individuals including 979 probands).

RESULTS

Measures of role function were heritable in models including neurocognitive domains and factor analytically derived neurocognitive summary scores and demographics as covariates; the most heritable estimate was obtained from the current GAS scores (h2=0.72). Neurocognition was not a significant contributor to heritability of role function.

CONCLUSIONS

Commonly assessed demographic and clinical indicators of functioning are heritable with a global rating of functioning being the most heritable. Measures of neurocognition had little impact on heritability of functioning overall. The family covariance for functioning, reflected in its heritability, supports the concept that interventions at the family level, such as evidenced-based family psychoeducation may be beneficial in schizophrenia.

Trichotillomania associated with dementia: a case report

Trichotillomania represents a syndrome of hair pulling in which patients compulsively and ritualistically pluck their hair in response to a sense of tension or urgency. This report documents a case of hair pulling associated with dementia. Neuropsychological testing demonstrated the deficits to be localized predominantly to the frontal lobe dysfunction.

Source memory in mild to moderate Alzheimer's disease

This research examined whether source memory is preserved in patients with mild to moderate Alzheimer's disease (AD). In Experiment 1, AD patients and normal elderly controls recalled true facts (information acquired outside of the experimental setting) and made-up facts (information acquired in the experiment), and they determined the source of these memories. Relative to controls, AD patients recalled fewer facts, but when they remembered this information, they attributed their learning to the correct source. In Experiment 2, memory of made-up facts was equated between groups by incorporating a 1-week recall delay for the controls. Again, AD patients accurately determined whether facts were learned inside or outside of the experiment. However, both groups performed at chance in terms of their memory for whether a made-up fact was read on a card or told by the examiner. The findings indicate relative preservation of source memory in the earliest stages of AD and are discussed in terms of methodological problems in testing source memory in impaired groups and in terms of frontal-lobe functioning.