Predicting genetic loading from symptom patterns in obsessive- compulsive disorder: a latent variable analysis.

BACKGROUND: Some symptom dimensions in obsessive-compulsive disorder (OCD) patients have a familial and putative genetic foundation, based on replicated findings in studies of sib-pairs with OCD. However, these symptom dimensions are all from exploratory factor analyses of Yale-Brown Obsessive-Compulsive Scale Symptom Checklist ratings based on non-empirically derived symptom categories, rather than individual symptoms. METHODS: In this study, we used a novel latent variable mixture model analysis to identify meaningful patient subgroupings. This was preceded by a confirmatory factor analysis of a 65-item OCD symptom inventory from 398 OCD probands, which yielded a five-factor solution. Data from all five symptom factors were used in a latent variable mixture model analysis, which identified two statistically separate OCD subpopulations. RESULTS: One group of probands had a significantly higher proportion of OCD-affected afflicted relatives (parents or close parental relatives), whereas the other group had a less prevalent familial OCD. The group with the more familial OCD was also found to have an earlier age of OCD onset, more severe OCD symptoms, and greater psychiatric comorbidity and impairment. CONCLUSIONS: Especially if the results are verified in other samples, this research paradigm, which identified characteristics of individuals with familial OCD, should prove useful in carrying out genome-wide linkage and association studies of OCD and may provide a model for other symptom-based studies of additional medical disorders.

Brain lesion and memory functioning: short-term memory deficit is independent of lesion location.

We analyzed the effects of patterns of brain lesions from penetrating head injuries on memory performance in participants of the Vietnam Head Injury Study (Grafman et al., 1988). Classes of lesion patterns were determined by mixture modeling (L. K. Muthén & B. O. Muthén, 1998-2004). Memory performance was assessed for short-term memory (STM), semantic memory, verbal episodic memory, and visual episodic memory. The striking finding was that large STM deficits were observed in all classes of brain-injured individuals, regardless of lesion location pattern. These effects persist despite frequent concomitant effects of depressive symptomatology and substance dependence. Smaller deficits in semantic memory, verbal episodic memory, and visual episodic memory depended on lesion location, in a manner roughly consistent with the existing neuropsychological literature. The theoretical and clinical implications of the striking, seemingly permanent STM deficits in individuals with penetrating head injuries are discussed.

Context, complexity, and cognitive processing in schizophrenia.

BACKGROUND: Cohen et al.'s (1990, 1999) concept of context has been employed to explain various schizophrenic cognitive deficits. Braver et al.'s (2001) modified definition allows us to link context to cognitive complexity and explain a range of our experimental findings. METHOD: Saccadic and manual responses to experimental paradigms involving familiar and unfamiliar versions of tasks varying in stimulus-response compatibility, response familiarity, and temporal factors were used. These include comparison of acoustic and visually driven saccades and antisaccades, manual and saccadic pattern reproduction, and colour (cognitively guided) saccades with two delay intervals. RESULTS: In one experiment, schizophrenic participants, unlike controls, made fewer errors on the auditory compared to the visual antisaccade task, suggesting that prepotent responses are more easily inhibited when stimulus-response compatibility is reduced. In a second experiment in which a left-right response sequence is reproduced manually or saccadically, schizophrenic performance is impaired when the novel and thus more complex saccadic response is required. In the third experiment, a colour signal is interpreted to determine the correct direction of a saccade. With two different blocked delay intervals, shortening the delay results in schizophrenic performance decline, suggesting difficulty adjusting to temporal context changes. CONCLUSION: These results, together with our previous findings (Schooler et al., 1997a; Zahn et al., 1998) suggest schizophrenic context processing deficits become increasingly evident as contexts become more complex. These results may be due to microgaps in schizophrenic individuals' maintenance of context.

Parental practices and willingness to ask for children's help later in life.

We examine how parents' relationships with their 13- to 25-year-old offspring affect the parents' willingness to ask them for help with financial and personal problems 20 years later. Husbands and wives were interviewed in 1974 and 1994; a child was interviewed in 1974. We used two aspects of parental style, responsiveness and restrictive dominance, to predict parents' willingness to request help from a child 20 years later. Structural equation modeling analyses revealed the following: (a) mothers' willingness to ask an adult child for help with a personal problem was increased by higher levels of responsiveness; (b) mothers' willingness to ask for financial help was increased by responsive and decreased by restrictive-dominant maternal behavior; and (c) neither responsive nor restrictive-dominant paternal behavior affected fathers' later willingness to ask an adult child for help of either kind.

The roles of fatalism, self-confidence, and intellectual resources in the disablement process in older adults.

In this study, the authors examined the relations between 3 psychological variables-fatalism, self-confidence, and intellectual resources-and the subsequent development of illness and disability 20 years later in an adult sample. Results indicated that greater fatalism, assessed in 1974, predicted greater difficulty in everyday cognitive tasks as well as illness in 1994. Higher self-confidence in 1974 was associated with lesser degrees of cognitive and fine motor difficulty in 1994. Greater intellectual resources in 1974 (a combination of intellectual flexibility and education) predicted less cognitive and gross motor difficulty as well as lesser degrees of illness in 1994. Some of these relations were stronger for older than for middle-aged individuals. Results are discussed in the context of models of the disablement process.

Causal connections between socio-economic status and health: reciprocal effects and mediating mechanisms.

Using structural equation modeling techniques on data from a nationally representative longitudinal survey, we first explored the reciprocal relationships between socio-economic status (SES) and health status. We then estimated the degree to which health-related lifestyles/behaviors and psychosocial distress are mediating mechanisms of these relationships. As predicted, SES positively affects health, and health positively affects SES. Although the causal path from SES to health is stronger than the reverse, these findings confirmed the hypothesis that both social causation and health selection contribute to social inequalities in health. In terms of the mediating mechanisms through which SES and health affect each other, more than a third of the overall SES-health relationship was accounted for by health-related lifestyles/behaviors and psychosocial distress. A notable part of the effect of SES on health is due to differences in psychological distress, with the effects of health-related lifestyles/behaviors being much smaller. On the other hand, in terms of the effects of health on SES, differences in weight and sleeping behavior are more important than psychological distress.

Use It-and Keep It, Longer, Probably: A Reply to Salthouse (2006).

In this article, I call into serious question Salthouse's (2006) conclusions evaluating and disparaging the validity of the "use it or lose it" hypothesis regarding mental exercise and mental aging. I do so, in some part, by using data not discussed by Salthouse. The core of my argument relies heavily on a critical assessment of the conclusions that Salthouse derived from both his theoretical reasoning and his review of the literature. The more judicious conclusion I reach is that, although the whole story regarding cognitive function and aging is not known, at some level and to some degree, "using" it often delays the eventuality of "losing" it.