Comparison of short- and long-term dynamic group psychotherapy: randomised controlled trial. BJP, 203, . The first author's affiliations (p. 286) should read: Steinar Lorentzen, MD, PhD, Institute of Clinical Medicine, University of Oslo, and Department of Research and Development, Clinic for Mental Health and Addiction, Oslo University Hospital, Norway.

Adjunctive pharmacotherapy for cognitive deficits in schizophrenia: meta-analytical investigation of efficacy. BJP, 203, . In Fig. 1 (p. 176) the 95% CI bars and diamonds were mismatched and wrongly sized with respect to the results of the studies reported; a corrected figure appears below. In calculating the effect size for negative symptoms for Buchanan et al (2007), standard errors were interpreted as standard deviations in the original published paper. Here, we correct the changes in effect size for negative symptoms for Buchanan et al, changing our result from a d-value of 0.75 to −0.10 for this study (changed in revised Fig. 1, below).

Accordingly, overall effect size improvement of negative symptoms in response to glutamate agonists is changed to 0.42 (P = 0.004) from 0.62 (P = 0.000); resulting text changes follow. Summary (p. 172) the second sentence of the Results should read: Cholinergic and glutamatergic agents produced small-to-moderate effect-size improvements on negative symptoms (d = 0.54 and d = 0.42 respectively), and small effect-size improvements on general symptoms (d = 0.46 and d = 0.41 respectively). Table 2 (p. 175), data relating to ‘Glutamatergic agonists/Negative symptoms’ should read: study n = 7; effect size, 0.42; s.e. = 0.15; 95% CI 0.13-0.71; z = 2.84; P = 0.004; Q_w = 12.17; d.f.= 6; P = 0.06; N = 22. In the Results, under ‘Effects of cognitive-enhancing medication on symptoms’, the effect-size improvement in measures of negative symptoms reported for glutamate agonists should be d = 0.42, 95% CI 0.13-0.71. The effect size reduction in negative symptoms referred to in the fifth sentence of the Discussion (p. 175) should be d = 0.54 and 0.42 respectively.

Fig. 1 Forest plot of negative symptom improvement among placebo-controlled studies of cholinergic and glutamatergic medications for cognitive enhancement in schizophrenia.

AChEI, acetylcholinesterase inhibitor.