Standardized web-based cognitive behavioural therapy of mild to moderate depression: a randomized controlled trial with a long-term follow-up.

Depression is common but undertreated. Web-based self-help provides a widely accessible treatment alternative for mild to moderate depression. However, the lack of therapist guidance may limit its efficacy. The authors assess the efficacy of therapist-guided web-based cognitive behavioural treatment (web-CBT) of mild to moderate depression. Fifty-four individuals with chronic, moderate depression participated in a randomized wait-list controlled trial, with an 18-month follow-up (immediate treatment: n = 36, wait-list control: n = 18). Primary outcome measures were the Beck Depression Inventory (BDI-IA) and the Depression scale of the Symptom Checklist-90-Revised (SCL-90-R. DEP). Secondary outcome measures were the Depression Anxiety Stress Scales and the Well-Being Questionnaire. Five participants (9%) dropped out. Intention-to-treat analyses of covariance revealed that participants in the treatment condition improved significantly more than those in the wait-list control condition (.011 < p < .015). With regard to the primary measures, between-group effects (d) were 0.7 for the BDI-IA and 1.1 for the SCL-90-R DEP. Posttest SCL-90- R DEP scores indicated recovery of 49% of the participants in the treatment group compared with 6% in the control group (odds ratio = 14.5; p < .004). On average, the effects were stable up to 18 months (n = 39), although medication was a strong predictor of relapse. The results demonstrate the efficacy of web-CBT for mild to moderate depression and the importance of therapist guidance in psychological interventions.

CYP1A2 activity is an important determinant of clozapine dosage in schizophrenic patients.

Clozapine is an effective atypical antipsychotic drug applied in the treatment of resistant schizophrenia. The drug is mainly metabolized by cytochrome P-450 (CYP) enzymes especially the isozyme CYP1A2. Remarkably, the effective dosage varies widely among patients, making it necessary to individualize drug therapy with clozapine. The explanation for dosage variation may be differences in drug metabolism, and more specifically of CYP1A2 activity. This study is aimed at determining to what extent variability in clozapine dose can be explained by pharmacokinetic (PK) factors and more specifically by CYP1A2 activity in effectively treated psychiatric patients. In 22 evaluable patients with a schizophrenic disorder chronically using clozapine, the CYP1A2 activity and the clozapine clearance were estimated. For calculation of the pharmacokinetic parameters of clozapine, population PK software based upon Bayesian analysis was used. Caffeine clearance was estimated with the paraxanthine/caffeine ratio and served as estimate of CYP1A2 activity.A significant linear relationship was found between the clozapine dose and clozapine clearance (R: 0.71; P<0.05), whereas no relationship was found between clozapine dosage and clozapine serum trough concentration. Moreover, individual caffeine and clozapine clearances were found to be significantly related (R: 0.62; P<0.05) as were clozapine dose per kg body weight and P/C mol ratio (R: 0.44; P<0.05). We conclude that CYP1A2 activity is an important determinant of the variability of effective clozapine doses in psychiatric patients.