Jeffrey S. Berman

Osteopontin (OPN) is a phosphorylated acidic glycoprotein that has been implicated in a number of physiological and pathological events, including maintenance or reconfiguration of tissue integrity during inflammatory processes. As such, it is required for stress-induced bone remodeling and certain types of cell-mediated immunity. It also acts in dystrophic calcification, coronary restenosis, and tumor cell metastasis. An RGD-containing protein, OPN exists both as an immobilized ECM molecule in mineralized tissues and as a cytokine in body fluids; it is not a significant part of typical nonmineralized ECM.

Previous quantitative reviews of research on the efficacy of psychotherapy for depression have included only a subset of the available research or limited their focus to a single outcome measure. The present review offers a more comprehensive quantitative integration of this literature. Using studies that compared psychotherapy with either no treatment or another form of treatment, this article assesses (a) the overall effectiveness of psychotherapy for depressed clients, (b) its effectiveness relative to pharmacotherapy, and (c) the clinical significance of treatment outcomes. Findings from the review confirm that depressed clients benefit substantially from psychotherapy, and these gains appear comparable to those observed with pharmacotherapy. Initial analysis suggested some differences in the efficacy of various types of treatment; however, once the influence of investigator allegiance was removed, there remained no evidence for the relative superiority of any 1 approach. In view of these results, the focus of future research should be less on differentiating among psychotherapies for depression than on identifying the factors responsible for improvement.

We examined 17 meta-analyses of comparisons of active treatments with each other, in contrast to the more usual comparisons of active treatments with controls. These meta-analyses yielded a mean uncorrected absolute effect size for Cohen's d of .20, which is small and non-significant (an equivalent Pearson's r would be. 10). The smallness of this effect size confirms Rosenzweig's supposition in 1936 about the likely results of such comparisons. In the present sample, when such differences were corrected for the therapeutic allegiance of the researchers involved in comparing the different psychotherapies, these differences tend to become even further reduced in size and significance, as shown previously by Luborsky, Diguer, Seligman, et al. (1999).

This report examines a possible distortion in the results of comparative treatment studies due to the association of the researcher's treatment allegiances with outcomes of those treatments. In eight past reviews a trend appeared for significant associations between the researcher's allegiance and outcomes of treatments compared. In a new review of 29 studies of treatment comparisons, a similar trend appeared. Allegiance ratings were based not only on the usual reprint method, but also on two new methods: ratings by colleagues who knew the researcher well, and self-ratings by the researchers themselves. The two new allegiance methods Interco related only moderately, but each allegiance measure correlated significantly with outcomes of the treatments compared, and when combined, the three measures explained 69% of the variance in outcomes Such an association can distort comparative treatment results. Our report concludes with how the researcher's allegiance may become associated with treatment outcomes and how studies should deal with these associations.