Substance use and violent behavior in adolescence

The relation between substance use and violent behavior in adolescence is reviewed, and each of five competing models of this relation is examined. I begin by presenting background material on adolescent substance use and adolescent violence. I then describe five different models that have been proposed to explain the association between substance use and violent behavior. Next, I review the adolescent literature concerning substance use and violence, noting methodological weaknesses that have plagued this research. I conclude with an evaluation of the five models and suggestions for future research.     

Rehabilitating care

The feminist ethic of care has often been criticized for its inability to address four problems--the problem of exploitation as it threatens care givers, the problem of sustaining care-giver integrity, the dangers of conceiving the mother-child dyad normatively as a paradigm for human relationships, and the problem of security social justice on a broad scale among relative strangers. We argue that there are resources within the ethic of care for addressing each of these problems, and we sketch strategies for developing the ethic more fully.     

The measurement of imagery ability

When variations in imagery ability are used to predict task performance, distinct and consistent relationships do not tend to emerge. A selective review of studies is undertaken to outline some basic reasons why individual difference measures of imagery are often so unsuccessful. Relevant studies concerning the learning and performance of motor skills are examined in some detail. It is concluded that the major problem in these studies is the types of imagery tests that have been employed; these tests have not adequately measured imagery ability. A recently developed instrument, the Movement Imagery Questionnaire, which has been designed to assess individual differences in visual and kinesthetic imagery of movement is discussed.     

Pharmacological dissociation of memory: anisomycin, a protein synthesis inhibitor, and leupeptin, a protease inhibitor, block different learning tasks

Inhibition of protein synthesis by anisomycin for a short duration impairs memory of a one-trial inhibitory avoidance task in rats. Memory of escape conditioning involving eight trials is disrupted only if the duration of protein synthesis is prolonged by repeated injections. In marked contrast, olfactory memory of rats trained on two odor discriminations is not affected by anisomycin even if the duration of inhibition is prolonged and the number of trials is reduced to a minimum. In previous work, leupeptin, a thiol proteinase inhibitor, was shown to impair olfactory discrimination learning, but left inhibitory and avoidance conditioning intact. Together, these results provide a pharmacological double dissociation of memory, and suggest that the same chemistries, or mixtures of chemistries, may not be involved in all types of memory.     

Completely nonmetric multidimensional scaling

Most of the distance models underlying multidimensional scaling assume that if a stimulus y is between the stimuli x and z on each dimension, then x and z should be the farthest apart of the three stimuli. An iterative algorithm is described that uses only this betweenness prediction to infer the ordering of a set of stimuli on each of one or two dimensions. Applied to previously published semantic similarity data, this algorithm produced two-dimensional configurations that were similar in appearance to Euclidean configurations but generally involved fewer violations of the betweenness prediction.     

Exploration and avoidance in rats with lesions in amygdala and piriform cortex

Lesions localized to specific areas of the amygdala and overlying cortex in rats produced differential effects in several behavioral tasks. Three different types of lesions were tested: central, basolateral, and cortex lateral to the amygdala. Lesions restricted to the central nucleus produced increased activity on all parameters studied in an open-field test, but the other two groups were not changed. In one-way active avoidance all three groups with lesions showed deficits. The most pronounced change was observed in the central group. All groups showed the same degree of retention loss, but in forced extinction of one-way active avoidance after retraining, the cortical and basolateral groups were most defective. A fear-reduction hypothesis is proposed for the central lesion. The basolateral and cortical areas may be more specifically involved in passive avoidance behavior.     

Differential indications for desipramine--results of a controlled multiclinical study]

The antidepressants desipramine and imipramine were compared within the framework of a multiclinical study performed under the conditions of a controlled clinical experiment. There has been found a time-different remission of affective symptoms, which was not detectable for the inhibition of drive. The tachythymoleptic action of desipramine is discussed with reference to these results. Evaluation of the possibility of controlling affects shows different ranges of activity of desipramine and imipramine, with desipramine influencing especially negative psychoenergetic symptoms in the area of drives and emotions and imipramine, restrictive symptoms in addition to differential phenomena of the psychomotor expression.