The clock drawing test is an important contribution to the Mini Mental State Examination in screening for cognitive impairment.

BACKGROUND: The clock drawing test (CDT) and the Mini Mental State Examination (MMSE) are frequently used screening instruments for cognitive impairment, however, the precise contribution of the CDT to the MMSE is largely unknown. METHODS: We studied patients with subjective cognitive impairment (SCI, n = 481), mild cognitive impairment (MCI, n = 628) and Alzheimer's disease (AD, n = 1099). Discrimination between patients was examined with multiple logistic regression, adjusted for age, sex, and education. Four groups were constructed based on a normal/abnormal MMSE (cut-off <24/30) versus normal/abnormal CDT (cut-off ≤2/3). Visually rated medial temporal lobe atrophy (MTA) on CT was used as parameter of neurodegeneration. RESULTS: The CDT significantly contributed to the MMSE in discriminating SCI from both MCI and AD patients. Our four group analyses showed that of those patients with a normal MMSE and incorrectly classified as SCI, an abnormal CDT could significantly identify 10.0% as MCI and 13.2% as AD. Among those with an abnormal MMSE, the percentage AD patients shifted from 53.1% to 82.1% due to an abnormal CDT. Presence of an abnormal CDT was significantly related to MTA increase, regardless of the MMSE score. CONCLUSION: The CDT is an important additional screening tool to the MMSE. An abnormal CDT with a normal MMSE is an indicator for cognitive impairment. An abnormal CDT in combination with an abnormal MMSE can be considered as an indicator of disease progression.

The influence of informant characteristics on the reliability of family history interviews.

Family history interviews are widely used in psychiatric research, as well as in genetic and twin studies, and provide a way to collect family history information quickly and economically. To obtain a valid assessment of family history, it is important to investigate which family member will be able to provide accurate information. Previous research shows that the validity of family history reporting can be influenced by characteristics of the informant, such as age, gender and personal history of psychiatric disorder. The aim of this study was to investigate the role of a subject's position in a pedigree on the validity of data collection. Family history data on diabetes and psychiatric disorders were collected in three generations of 33 families by interviewing both an index subject (3rd generation) and his or her mother (2nd generation). Mothers were shown to report higher rates of diabetes and psychiatric disorder in the family compared to the index subjects. There was no significant difference in the disease rate reported by male and female index subject. Mothers who experienced a depressive episode indicated significantly more family members as having a psychiatric disorder than mothers who never experienced such an episode. This could be explained by the presence of informant bias, but may also result from the fact that depression is a heritable disorder and is therefore actually more prevalent in these families. Our findings suggest that family interview data should be collected by interviewing subjects who have a central position in the pedigree and can therefore provide information on his/her own generation, the previous and the next. In addition, psychiatric status of the informant should be carefully addressed.

The association between intelligence scores and family history of psychiatric disorder in schizophrenia patients, their siblings and healthy controls.

BACKGROUND: The degree of intellectual impairment in schizophrenia patients and their relatives has been suggested to be associated with the degree of familial loading for schizophrenia. Since other psychiatric disorders are also more present in relatives of schizophrenia patients, the definition of family history should be broadened. The association between family history for psychiatric disorder and intelligence scores was investigated in patients with non-affective psychosis, their unaffected siblings and controls. METHODS: A sample of 712 schizophrenia proband families (696 patients and 766 siblings) and 427 healthy control families (517 subjects) participated in this study. Family history of psychiatric disorder was determined while excluding the data of the participating schizophrenia patient. A dichotomous division was made between families with no first- or second degree relative with psychiatric disorder and families with one or more affected relatives. Total intelligence scores were estimated by admission of the short form of the Wechsler Adult Intelligence Scale III. RESULTS: A significant interaction was found between family history of psychiatric disorder and clinical status (F(2,1086.87)= 4.17; p=.016). Patients with a positive family history of psychiatric disorder obtained higher intelligence scores compared to patients with no family history (mean IQ scores are 95.52 and 92.72) with an opposite effect in controls (mean IQ scores are 108.71 and 111.19). No significant difference was found between siblings of schizophrenia patients with or without a positive family history (mean IQ scores are 102.98 and 103.24). CONCLUSION: In patients with schizophrenia, a negative family history of psychiatric disorder was associated with relatively low IQ suggesting that the etiology in these patients may involve environmental or genetic factors which are unique to the patient and are not observed in other relatives. Possible factors include severe environmental stressors containing premature birth or brain injury and genetic factors (e.g de novo Copy Number Variants).