Urinary free cortisol and childhood trauma in cocaine dependent adults

OBJECTIVE: To examine whether childhood trauma may have a relationship to hypothalamic-pituitary-adrenal (HPA) axis function as an adult. METHODS: Forty-six withdrawn cocaine dependent patients participated in 24-h urine collections for determination of urinary-free cortisol (UFC) and completed the Childhood Trauma Questionnaire (CTQ). RESULTS: Patients with a mean UFC output below the median had significantly higher CTQ scores for childhood sexual abuse than patients with UFC outputs above the median. Multiple regression analysis showed that both childhood emotional neglect and sexual abuse were independently associated with UFC outputs. CONCLUSION: These cross sectional data, in a sample of middle-aged cocaine dependent patients, suggest the possibility that childhood trauma may have an effect on HPA axis function and thus predispose to psychiatric disorders. Further studies are needed in different samples.     

Retrieval-induced forgetting in Alzheimer's disease

It is claimed that Alzheimer's disease (AD) patients show reduced inhibitory processing and this has been put forward as a reason why AD patients make intrusion errors at recall. However, the evidence to date has been equivocal, because non-inhibitory mechanisms can account for the pattern of findings. Recently, however, a paradigm has been developed that is claimed to give a purer measure of inhibitory processing in episodic memory, the retrieval-induced forgetting (RIF) paradigm [Inhibitory Processes in Attention, Memory and Language, Academic Press, San Diego, 1994, p. 265; J. Exp. Psychol.: Learning, Memory Cognition 20 (1994) 1063; Psychol. Rev. 102 (1995) 68]. Thus, we were interested whether AD patients would show a deficit in inhibitory processing using this procedure. Participants studied lists of category cue-exemplar pairs (e.g. fruit-orange) then practised retrieval for a subset of items from a subset of categories before taking a final memory test for all studied items. As in previous work, inhibition was measured as the difference between final memory performance for unpractised items from practised categories, and unpractised items from unpractised categories. The results show that AD patients showed normal levels of inhibition with both tests of cued recall and category generation (CG). This suggests that a deficit in inhibitory processes during retrieval is not behind the high levels of intrusion errors made in recall in AD.     

Examining the utility of a temperament model for modelling non-melancholic depression

OBJECTIVE: Depression is currently modelled dimensionally, along severity, duration and recurrency dimensions. An alternative model allows dimensional expressions of temperament and personality to influence risk to onset as well as persistence. Here, we examine the utility of a temperament model. METHOD: A questionnaire assessing temperament dimensions and a number of depression variables was administered to a large routine general practice sample and with the temperament measure also completed by a small clinical sample. RESULTS: 'Anxious worrying' and 'irritable' dimensions were identified as internalizing and externalizing expressions of a trait anxiety dimension, three other 'temperament' dimensions (i.e. 'introversion', 'self-centred' and 'obsessive') were refined, while a 'self-blame' dimension intruded into the factor analytic solution. High scores on the 'anxious worrying' dimension were associated with all depression parameters. The 'irritable', 'introversion' and 'self-blame' dimensions were less clearly linked with depression variables, while higher scores on the 'self-centred' and 'obsessional' dimensions did not appear to increase the chance of depression onset, persistence or recourse to treatment. CONCLUSION: A temperament-based approach appears to have some conceptual utility in modelling depression, and particularly, the non-melancholic disorders. It is likely, however, to require complementing with refined at-risk personality dimensions.     

Higher levels of CSF homovanillic acid in recently abstinent cocaine-dependent patients

OBJECTIVE: The authors examined an index of dopaminergic neurotransmission in recently abstinent cocaine-dependent patients. METHOD: CSF concentrations of the dopamine metabolite homovanillic acid (HVA) were determined in 30 recently abstinent cocaine-dependent patients and 69 healthy comparison subjects. RESULTS: The cocaine-dependent patients had a significantly higher mean concentration of CSF HVA than did the healthy comparison group. CONCLUSIONS: Recently abstinent cocaine-dependent patients may show dysregulation of the central dopaminergic system.     

Vibrotaction and texture perception

Several recent studies support Katz's hypothesis that vibrotaction plays a role in the perception of tactile textures with elements too small and closely spaced to be processed spatially. For example, eliminating vibration by preventing movement of a stimulus surface across the skin compromises psychophysical scaling and discrimination of fine, but not coarse, textures. Fine-texture discrimination is also impaired when vibrotactile channels are desensitized by adaptation. A role for vibrotaction in texture perception is plausible, given the keenness of this submodality: the sensory qualities produced by a sinusoidal vibration uniquely specify its frequency and amplitude, and subjects can distinguish some complex vibrations that differ in waveform but have the same spectral components. Finally, imposed vibration can modify the perceived texture of a haptically-examined surface. Taken together, these lines of evidence support the view that vibrotaction is both necessary and sufficient for the perception of fine tactile textures.     

The positive effects of postnatal handling on defensive burying are more obvious in a situation that enlarges the potential coping responses

A recent study reported few effects of postnatal handling in the defensive burying test. Since the importance of testing conditions has been emphasised in this paradigm, the lack of handling effects in this test could be attributed to the testing situation. Our experiment was carried out to test whether postnatal handling in DA/HAN strain rats have positive effects in two situations of the defensive burying test: a no-hide situation, in which avoidance of the probe was not possible, and a hide situation, in which animals were allowed to avoid the probe by sheltering in a hiding compartment. Our results showed no difference between control and handled rats defensive reactions in the no-hide situation. However, the general coping style of handled rats was different, mostly by a higher level of exploration of the apparatus and of the probe. In the hide situation, the time spent burying the probe was significantly lower in handled rats and they also spent less time in the hiding compartment. Those results, along with approach/avoidance behaviours directed towards the probe demonstrate that postnatal handling do have some positive effects in the defensive burying test. In addition, our results also point out that testing situations in which complex coping strategies are available are appropriate to test the effects of early stimulation such as handling.