Clinical phenomenology

A cluster analysis of text message users based on their demand for text messaging: A behavioral economic approach

The goal of this study was to determine whether cluster analysis could be used to identify distinct subgroups of text message users based on behavioral economic indices of demand for text messaging. Cluster analysis is an analytic technique that attempts to categorize cases based on similarities across selected variables. Participants completed a questionnaire about mobile phone usage and a hypothetical texting demand task in which they indicated their likelihood of paying an extra charge to continue to send text messages. A hierarchical cluster analysis was conducted on behavioral economic indices, such as demand intensity, demand elasticity, breakpoint, and the maximum expenditure. With the cluster analysis, we identified 3 subgroups of text message users. The groups were characterized by (a) high intensity and low elasticity, (b) high intensity and medium elasticity, and (c) low intensity and high elasticity. In a demonstration of convergent validity, there were statistically significant and conceptually meaningful differences across the subgroups in various measures of mobile phone use and text messaging. Cluster analysis is a useful tool for identifying and profiling distinct, practically meaningful groups based on behavioral indices and could provide a framework for targeting interventions more efficiently.

Genetics, neuroscience and psychiatric classification

Some psychiatrists anticipate a revolution in psychiatric nosology, on the basis of emerging data from genetics and genomics. There are, however, good empirical and conceptual reasons to resist any such revolution. Basing an understanding of psychiatric entities on one of multiple biological (not to mention sociocultural and psychological) considerations is a specious method of approaching the project of psychiatric taxonomy. A classification system that lacks sufficient consensus on the phenomenology of those classified cannot be adequately buttressed by exclusively genetic accounts. This paper advocates a more diversely informed nosology that, in turn, fosters attention to broader diagnostic considerations. We explore more plausible ways in which genetics and genomics, in conjunction with neuroscience and other biological disciplines, can help to shape diagnostic classification in psychiatry. There are, of course, differing views on the degree of prominence that genetics should take in psychiatric diagnosis and classification. We outline these accounts in illustration of this continuum. Drawing on Wimsatt's work on robustness analysis, we dismiss optimistic scenarios about the potential nosological advantages of psychiatric genetics and genomics, and offer a novel defense of realism about psychiatric entities. We also briefly sketch an integrative methodology for psychiatric research and classification.

The development and reliability of the Mental Health Research Institute Unusual Perceptions Schedule (MUPS): an instrument to record auditory hallucinatory experience

The Mental Health Research Institute Unusual Perceptions Schedule (MUPS) is a comprehensive instrument developed to record subjects' experiences of auditory hallucinations as completely as possible. The Schedule comprises a semi-structured interview and documents the physical characteristics of auditory hallucinations such as their onset and course, number, volume, tone, location, as well as other phenomena associated with them such as delusions. In addition, other aspects of hallucinations, such as coping strategies, contributing factors and subjects' personal views and reactions are also explored. In a sample of 100 subjects drawn primarily from the in-patient wards at Royal Park Hospital the MUPS was found to be an acceptable instrument to subjects in the field. Interrater reliability assessed in a subsample of 30 subjects was found to be high at the level of the individual items. Whether used in whole or part, the MUPS provides a reliable and acceptable method of assessing patients' experience of auditory hallucinations.

Serum melatonin levels in schizophrenic and schizoaffective hospitalized patients

Conflicting results on changes of the diurnal melatonin rhythms of patients with affective disorders have been reported in the literature. The heterogeneous data may derive from the great discrepancy in the diagnostic criteria of different authors. A study of 12 schizoaffective and chronic schizophrenic psychotic patients found a constant pattern of an obliterated nocturnal melatonin rise only in the latter group. The presence or absence of the nocturnal melatonin rise was determined in drug-free hospitalized patients and remained unchanged despite 2 months of drug treatment including large doses of neuroleptics. This finding, when confirmed in a larger number of patients, could possibly serve as a marker for the type of mental disorder, drug to be applied and response expected.

Availability of schizophrenic patients and their families for genetic linkage studies: findings from the Maryland epidemiology sample

It has been suggested that collections of affected sib pairs, or their nuclear families, may be an efficient method for screening for genetic linkages in schizophrenia. We present the data collected in five years from 15 hospitals in the state of Maryland in an effort to determine if such a collection scheme will be feasible. Probands in our sample were eligible for inclusion in the sample if they were white, were age 16 years or older, and carried a research diagnosis of schizophrenia. Family data are reported for 258 probands. Using the most stringent category of affected (RDC schizophrenia) revealed ten families with two or more affected sibs. The broadest category of affected (any psychotic disorder or psychiatric hospitalization) identified only 36 families with two or more affected sibs. We conclude that, if schizophrenia is a heterogeneous disorder with decreased penetrance, an effort to collect multiplex nuclear families is unlikely to provide enough data to identify genetic linkage. Alternatively, an effort to seek out and collect larger multiplex, multigenerational families rather than a collection of affected sib pairs may be more efficacious.