When instructions don't help: Knowing the optimal strategy facilitates rule-based but not information-integration category learning.

Providing verbal or written instructions on how to perform optimally in a task is one of the most common ways to teach beginners. This practice is so widely accepted that scholarship primarily focuses on how to provide instructions, not whether these instructions help or not. Here we investigate the benefits of prior instruction on rule-based (RB) category-learning, in which the optimal strategy is a simple explicit rule, and information-integration (II) category-learning, in which the optimal strategy is similarity-based.

Modeling Response Time with Power Law Distributions.

This article overviews several contemporary models that assume power law scaling is a plausible description of the skewed right tails that are typical of response time distributions. The properties and markers of these distribution functions have implications for cognitive and neurophysiological dynamics. The power law hypothesis suggests studies should collect larger samples, and that analyses may combine individual subjects' data into a single set for a distribution-function contrasts.

Quantum mechanical calculation of spectral statistics of a modified Kepler problem.

For a modified Kepler problem, we reexamine jumps in the saturation spectral rigidity and large oscillations of the level number variance with near zero minima. Earlier discrepancy between the periodic orbit theory and numerical calculation is cleared by a quantum mechanical calculation. A new class of radial periodic orbits is included establishing a complete correspondence between the periodic orbit theory and the quantum mechanical approach.

Quantum jumps of saturation level rigidity and anomalous oscillations of level number variance in the semiclassical spectrum of a modified Kepler problem.

We observe numerically, and explain analytically, a previously unknown phenomenon of quantum-Hall-like jumps in saturation spectral rigidity in the semiclassical spectrum of a modified Kepler problem as a function of the interval center. These jumps correspond to integer decreases of the radial winding numbers in classical periodic motion. We also observe and explain single-harmonic-dominated oscillations of the level number variance with the width of the energy interval.

Persistence of strong correlations in the energy spectrum of a separable Hamiltonian system: the rectangular box.

The variance of the number of levels in an energy interval around a level with large quantum numbers (semiclassical quantization) is studied for a particle in a rectangular box. Sampling involves changing the ratio of the rectangle's sides while keeping the area constant. For sufficiently narrow intervals, one finds the usual linear growth with the width of the interval.

The effect of therapist/patient race- and sex-matching in individual treatment.

Aims: Equivocal findings of the effect that therapist and patient similarity plays in treatment outcome led us to examine the impact of race- and sex-matching on treatment retention and outcome for a sample of people seeking outpatient substance abuse treatment.

Design: Patient and therapist characteristics were crossed in a 2 x 2 factorial design. Matching effects were then tested using retrospective data.

Correlates of employment: a cohort study.

Employment is often viewed as a potent indicator of substance abuse treatment outcome. This study was conducted to determine if personality and/or demographic characteristics of a cohort of unemployed substance dependent persons presenting for addiction treatment might predict employment 9 months postadmission. By using stepwise discriminant function analysis, seven variables predictive of employment were identified.

A therapeutic use of the methadone fluvoxamine drug interaction.

Background: Methadone has been effectively used in the treatment of opiate dependence. Adequate dose and blood level have correlated with success in treatment. A number of factors including the regular use of alcohol, medications, and urinary pH can influence blood level and thereby effectiveness.

Therapist/patient race and sex matching: treatment retention and 9-month follow-up outcome.

Aims: The current study was conducted to (a) replicate previous findings regarding the effect of patient/therapist race and sex-matching as this relates to the early dropout rate of substance abusers, and (b) to extend previous work by examining the impact of such matching on treatment retention and 9-month outcome.

Design: Patient and therapist characteristics were crossed in a 2 x 2 factorial design. Matching effects were then tested using retrospective data.

A randomized controlled study of the effectiveness of intensive outpatient treatment for cocaine dependence.

Objective: A randomized controlled study design was used to compare the effectiveness of intensive outpatient treatment with individual outpatient counseling and a combination of individual and group outpatient counseling for cocaine-dependent patients.

Methods: Volunteers for this study were recruited from among first admissions to an inner-city, public-sector outpatient substance abuse clinic. In-treatment, end-of-treatment, and nine-month follow-up assessments were compared for participants randomly assigned for 12 weeks to one of three treatment modalities--weekly individual outpatient counseling, weekly individual counseling plus one weekly group session, or a newly designed intensive group treatment program consisting of three hours of group treatment three days a week.

Characteristics of cocaine-addicted individuals who abuse their partners.

The purpose of this study was to determine what proportion of individuals entering treatment for cocaine dependence admitted to battering an intimate partner and to compare the characteristics of those who were not identified as batterers. Of the 77 men in the sample, 38% were characterized as cocaine-dependent batterers. The batterers and nonbatterers were found to differ on a variety of background and assessment variables.

Underreporting of cocaine use at posttreatment follow-up and the measurement of treatment effectiveness.

Substance abusers, especially cocaine abusers, may underreport their substance use in outcome interviews. Follow-up interviews were conducted and urine specimens were obtained on 633 persons 9 months after admission to a 3-month cocaine treatment program. Although 422 (67%) reported no use of cocaine in the past 30 days, 134 of these (32%) had cocaine-positive urines.

Patient treatment choice and compliance. Data from a substance abuse treatment program.

The authors tested the hypothesis that patients (treatment-seeking cocaine-dependent persons) given the opportunity to choose between treatment approaches would do better than patients randomly assigned to the same approaches in treatment retention and 9-month outcome. Subjects were 34 patients who voluntarily chose to enter individual therapy 1 hour per week (IND) and 33 who chose intensive group therapy for 3 hours, 3 times weekly (INT). There were no significant differences between these two groups on demographic, personality, or addiction severity variables or in treatment retention or 9-month outcome.

Learned helplessness and cocaine dependence: an investigation.

Low personal control and a sense of meaninglessness of life, attributes associated with a pattern of human learned helplessness, have also been described as contributing to the onset of adolescent drug use, as well as the maintenance of chronic substance abuse. However, despite its intuitive appeal as an etiologic factor, the absence of psychometrically sound and easily administered measures of learned helplessness has limited the ability of researchers to empirically test its role in the addiction process. Accordingly, the publication by Quinless and Nelson (1988) of a relatively brief Learned Helplessness Scale (LHS) led us to administer it to a sample of 30 consecutive cocaine dependent individuals seeking treatment for the first time at our facility.

Prediction of length of stay in an inpatient dual diagnosis unit.

The institution of prospective payment systems, in which flat fees are paid per discharge, raised the concern that hospitals might preferentially admit patients expected to have a short length of stay (LOS). This concern presupposes that intake workers could accurately predict psychiatric hospitalization LOS, but this does not appear to have been empirically demonstrated. Accordingly, we examined the ability of two psychiatrists heading separate treatment teams on an inpatient, dual-diagnosis unit and a program coordinator who worked with both teams to predict LOS for 94 patients consecutively admitted to one or the other of these teams.

Gender differences and similarities in African-American crack cocaine abusers.

Recent interest in women's health and patient-treatment matching has focused attention on gender differences among substance abusers. This article seeks to extend research in this area to African-American crack cocaine abusers. It describes gender differences and similarities in a large sample (652 males and 595 females) of this important group of patients at a publicly funded, inner-city intensive outpatient clinic.

Predicting compliance of dual diagnosis inpatients with aftercare treatment.

Objective: Patients with comorbid diagnoses of a substance use disorder and at least one other axis I mental disorder have low rates of compliance with aftercare. The purpose of the study was to identify predictors of noncompliance among dual diagnosis inpatients.

Methods: Characteristics of 48 dual diagnosis inpatients were examined.