PubMed Health⌕ Search

Biomedical subjects

P Crits-Christoph

Publications and source records attributed to P Crits-Christoph.

At least 19 recordsLinked to original sources
PubMed2006

Power analyses for correlations from clustered study designs.

Power analysis constitutes an important component of modern clinical trials and research studies. Although a variety of methods and software packages are available, almost all of them are focused on regression models, with little attention paid to correlation analysis. However, the latter is arguably a simpler and more appropriate approach for modelling concurrent events, especially in psychosocial research. In this paper, we discuss power and sample size estimation for correlation analysis arising from clustered study designs. Our approach is based on the asymptotic distribution of correlated Pearson-type estimates. Although this asymptotic distribution is easy to use in data analysis, the presence of a large number of parameters creates a major problem for power analysis due to the lack of real data to estimate them. By introducing a surrogacy-type assumption, we show that all nuisance parameters can be eliminated, making it possible to perform power analysis based only on the parameters of interest. Simulation results suggest that power and sample size estimates obtained under the proposed approach are robust to this assumption.

Clinical Trials as Topic↗
PubMed2004

Power analyses for longitudinal trials and other clustered designs.

Existing methods for power and sample size estimation for longitudinal and other clustered study designs have limited applications. In this paper, we review and extend existing approaches to improve these limitations. In particular, we focus on power analysis for the two most popular approaches for clustered data analysis, the generalized estimating equations and the linear mixed-effects models. By basing the derivation of the power function on the asymptotic distribution of the model estimates, the proposed approach provides estimates of power that are consistent with the methods of inference for data analysis. The proposed methodology is illustrated with numerous examples that are motivated by real study designs.

Clinical Trials as Topic↗
PubMed2003

Generalized covariance-adjusted canonical correlation analysis with application to psychiatry.

The lack of control over covariates in practice motivates the need for their adjustment when measuring the degree of association between two sets of variables, for which canonical correlation is traditionally used. In most studies however, there is also a lack of control over the attributes of responses for the sets of variables of interest. In particular, a portion of the response variable may be continuous and the other discrete. For such settings, the traditional partial canonical correlation approach is restrictive, since a covariate-adjustment for a set of continuous variables is assumed. By ignoring the assumption of continuous variates and proceeding with a partial canonical correlation analysis in the presence of continuous and discrete variates, results in canonical correlation estimates that are not consistent. In this paper we generalize the traditional partial canonical correlation approach to covariate-adjustment by allowing the response variables to contain continuous, as well as discrete, variates. The methodology is illustrated with a psychiatric application for examining which sleep variables relate to which depressive symptoms, as measured by commonly used constructs that presents with both continuous and discrete outcomes.

Analysis of Variance↗
PubMed2001

Therapeutic alliance as a predictor of outcome and retention in the National Institute on Drug Abuse Collaborative Cocaine Treatment Study.

The authors examined the relation between therapeutic alliance, retention, and outcome for 308 cocaine-dependent outpatients participating in the National Institute on Drug Abuse Collaborative Cocaine Treatment Study. High levels of alliance were observed in supportive-expressive therapy (SE), cognitive therapy (CT), and individual drug counseling (IDC), and alliance levels increased slightly but significantly from Session 2 to Session 5 in all groups. In contrast to other studies, alliance was not a significant predictor of drug outcome. However, alliance did predict patient retention differentially across the 3 treatments. In SE and IDC, either higher levels of alliance were associated with increased retention or no relationship between alliance and retention was found, depending on the time alliance was measured. In CT, higher levels of alliance were associated with decreased retention.

Adult↗
PubMed2001

Impact of psychosocial treatments on associated problems of cocaine-dependent patients.

A previous report from the National Institute on Drug Abuse Collaborative Cocaine Treatment Study (P. Crits-Christoph et al., 1999) found relatively superior cocaine and drug use outcomes for individual drug counseling plus group drug counseling compared with other treatments. Using data from that study, the authors examined the relative efficacy of 4 treatments for cocaine dependence on psychosocial and other addiction-associated problems. The 487 patients were randomly assigned to 6 months of treatment with cognitive therapy, supportive-expressive therapy, or individual drug counseling (each with additional group drug counseling), or to group drug counseling alone. Assessments were made at baseline and monthly for 6 months during the acute treatment phase, with follow-up visits at 9 and 12 months. No significant differences between treatments were found on measures of psychiatric symptoms, employment, medical, legal, family-social, interpersonal, or alcohol use problems. The authors concluded that the superiority of individual drug counseling in modifying cocaine use does not extend broadly to other addiction-associated problems.

Adolescent↗
PubMed2001

Early improvement during manual-guided cognitive and dynamic psychotherapies predicts 16-week remission status.

This study examined the extent to which improvement from baseline to weeks 2, 3, and 4 on the Beck Depression Inventory and Beck Anxiety Inventory predict week 16 clinical remission for patients with major depressive disorder, generalized anxiety disorder, and/or obsessive-compulsive or avoidant personality disorders who were receiving manual-based psychotherapies. Logistic regression and receiver-operator characteristic analyses revealed relatively accurate identification of remitters and nonremitters based on improvement from baseline to sessions 2 to 4 in both original and cross-validation samples. Predictive success did not vary as a function of diagnosis, treatment type (cognitive or dynamic), or treatment status (short-term or long-term). The clinical implications of the results are discussed.

Adult↗
PubMed2000

Self-help group attendance and participation among cocaine dependent patients.

The authors examined frequency and patterns of self-help group attendance and active participation over a 6-month period among 411 patients receiving treatment in the NIDA Collaborative Cocaine Treatment Study. Nearly two-thirds of patients attended at least one self-help group, and nearly all of these actively participated. Alcoholics Anonymous and Narcotics Anonymous meetings were attended most frequently. Statistical analyses included chi square, one-way analyses of variance, and cluster techniques. While patterns of attendance were relatively consistent over time, findings suggest that a treatment emphasizing the importance of self-help groups is likely to encourage more self-help group attendance and participation over time.

Adolescent↗
PubMed2000

Alliance predicts patients' outcome beyond in-treatment change in symptoms.

The authors examined the relations among therapeutic alliance, outcome, and early-in-treatment symptomatic improvement in a group of 86 patients with generalized anxiety disorders, chronic depression, or avoidant or obsessive-compulsive personality disorder who received supportive-expressive dynamic psychotherapy. Although alliance at Sessions 5 and 10, but not at Session 2, was associated with prior change in depression, alliance at all sessions significantly predicted subsequent change in depression when prior change in depression was partialed out. The results are discussed in terms of the causal role of the alliance in therapeutic outcome.

Adult↗
PubMed2000

The role of therapist characteristics in training effects in cognitive, supportive-expressive, and drug counseling therapies for cocaine dependence.

The role of therapist characteristics in therapy training was examined for 62 therapists in a multisite psychotherapy outcome study that included cognitive therapy (CT), supportive-expressive (SE) psychodynamic therapy, and individual drug counseling (IDC) for cocaine-dependent patients. Demographic variables and experience and competence ratings prior to training were correlated with measures of change in competence during the training phase. Higher competence ratings before training were associated with greater change in competence for SE and higher average competence for IDC. More years of experience were associated with greater change in competence for CT therapists, but more hours of pre-training supervision in the CT treatment modality were associated with less change.

Adult↗
PubMed1999

Psychosocial treatments for cocaine dependence: National Institute on Drug Abuse Collaborative Cocaine Treatment Study.

BACKGROUND: This was a multicenter investigation examining the efficacy of 4 psychosocial treatments for cocaine-dependent patients. METHODS: Four hundred eighty-seven patients were randomly assigned to 1 of 4 manual-guided treatments: individual drug counseling plus group drug counseling (GDC), cognitive therapy plus GDC, supportive-expressive therapy plus GDC, or GDC alone. Treatment was intensive, including 36 possible individual sessions and 24 group sessions for 6 months. Patients were assessed monthly during active treatment and at 9 and 12 months after baseline. Primary outcome measures were the Addiction Severity Index-Drug Use Composite score and the number of days of cocaine use in the past month. RESULTS: Compared with the 2 psychotherapies and with GDC alone, individual drug counseling plus GDC showed the greatest improvement on the Addiction Severity Index-Drug Use Composite score. Individual group counseling plus GDC was also superior to the 2 psychotherapies on the number of days of cocaine use in the past month. Hypotheses regarding the superiority of psychotherapy to GDC for patients with greater psychiatric severity and the superiority of cognitive therapy plus GDC compared with supportive-expressive therapy plus GDC for patients with antisocial personality traits or external coping style were not confirmed. CONCLUSION: Compared with professional psychotherapy, a manual-guided combination of intensive individual drug counseling and GDC has promise for the treatment of cocaine dependence.

Adult↗
PubMed1999

Reliability and base rates of interpersonal themes in narratives from psychotherapy sessions.

We present an analysis of the reliability and base rates of the interpersonal contents of narratives told by patients in psychotherapy. Trained judges rated two samples, including 60 opiate-dependent patients in cognitive or psychodynamic therapy and 72 depressed patients in cognitive or interpersonal therapy. Using a comprehensive system based upon a circumplex model and involving 104 separate categories, we found that most categories of interpersonal behavior could be rated reliably. Potential problem categories were identified and strategies for increasing reliability are discussed. In particular, categories related to the concept of the introject (what the self does to the self) had low reliability. An analysis of the base rates of interpersonal themes revealed that issues related to autonomy/ assertion were most prevalent, although some differences between the two samples were evident. The implications of the results for research on narratives and models of psychotherapy are discussed.

Adult↗
PubMed1999

Current developments in psychosocial treatments of alcohol and substance abuse.

This article reviews recent findings and new developments in alcohol and substance abuse treatment over the past 2 years. Outcome results from two large clinical trials: Project MATCH (Matching Alcoholism Treatments to Client Heterogeneity) for alcohol dependent patients; and the National Institute on Drug Abuse Collaborative Cocaine Treatment Study for cocaine dependent patients; and the naturalistic Drug Abuse Treatment Outcome Study have yielded important results on the possibility of patient treatment matching. The promising community reinforcement approaches have been expanded to opiate dependent and homeless populations. Finally, a number of studies point to the important role of self-help groups and the power of 12-step-based treatment approaches.

Alcoholism↗
PubMed1999

Alliance and technique in short-term dynamic therapy.

We review existing studies on the extent to which the alliance and techniques predict the outcome of short-term dynamic psychotherapy (STDP). Although the alliance has been found to relate to outcome in diverse psychotherapies, evidence for its role in STDP is more inconsistent. Studies of technique factors have provided support for the relation of competence with exploratory interventions to outcome. Less support for the role of specific transference interpretations was found. Little empirical support exists for the notion that the technical factors are most potent in the context of a positive alliance, although adequate studies of this interaction are scarce. Similarly, adequate studies that attempt to tease apart the extent to which technical factors influence the alliance, and vice versa, are also rare. Despite the methodological limitations of research in this area, the fact that there are some consistent findings relating techniques to outcome suggests that nonspecific relationship factors do not by themselves account for the changes found over the course of STDP. Moreover, such findings encourage additional efficacy and process research on STDP. Some suggestions for future research are presented.

Humans↗
PubMed1999

Quality of life: expanding the scope of clinical significance.

Clinical researchers have turned their attention to quality of life assessment as a means of broadening the evaluation of treatment outcomes. This article examines conceptual and methodological issues related to the use of quality of life measures in mental health. These include the lack of a good operational definition of the construct, the use of subjective versus objective quality of life indicators, and the nature of the relationship between symptoms and quality of life judgments. Of special concern is the ability of quality of life measures to detect treatment-related changes. The authors review the application of quality of life assessment across diverse patient groups and therapies and provide recommendations for developing comprehensive, psychometrically sophisticated quality of life measures.

Humans↗
PubMed1998

Predictors of dropout from psychosocial treatment of cocaine dependence.

The current study assessed demographic, drug and psychiatric predictors of dropout in the pilot/training phase of a large, multi-site psychotherapy outcome study for patients with cocaine dependence. The different predictors of dropout were assessed throughout the phases of the study: screening, intake, stabilization and assessment phase, and following randomization to treatment. Results showed that (1) younger patients were less likely to keep their intake appointment. (2) Of the patients who had an intake visit, those who did not complete high school and with more days of cocaine use in the previous month were less likely to complete an initial stabilization and assessment phase requiring 1 week of abstinence from all drugs. A survival analysis was used to examine time to dropout for the 286 patients randomized to individual treatment. (3) Again, younger age was associated with dropout after randomization. (4) Drug use variables did not predict time to dropout. (5) Presence of any current Axis I disorder was associated with later dropout from treatment. Minority treatment information seekers and treatment initiators were less likely to go on to complete the full treatment program.

Adult↗
PubMed1998

Empirically supported individual and group psychological treatments for adult mental disorders.

The experimental literature on individual and group psychological treatments for adult disorders is reviewed. For each of the 11 disorders or problems covered, treatments that fall into the following categories, as defined by D.L. Chambless and S. D. Hollon (1998), are identified: efficacious and specific, efficacious, and possibly efficacious. Behavioral and cognitive-behavioral treatments dominate the lists, especially in the anxiety disorders, with notable exceptions. Reasons for the hegemony of the behavioral and cognitive modalities are discussed, and some limitations of the empirically supported treatment concept are addressed. Continued research is recommended on Aptitude x Treatment interactions, cost-benefit ratios, and generalization of treatments to a variety of patient populations, therapists, and treatment settings.

Adult↗