Toshi A. Furukawa

The performance of the K6 and K10 screening scales for psychological distress in the Australian National Survey of Mental Health and Well-Being

BACKGROUND Two new screening scales for psychological distress, the K6 and K10, have been developed but their relative efficiency has not been evaluated in comparison with existing scales. METHOD The Australian National Survey of Mental Health and Well-Being, a nationally representative household survey, administered the WHO Composite International Diagnostic Interview (CIDI) to assess 30-day DSM-IV disorders. The K6 and K10 were also administered along with the General Health Questionnaire (GHQ-12), the current de facto standard of mental health screening. Performance of the three screening scales in detecting CIDI/DSM-IV mood and anxiety disorders was assessed by calculating the areas under receiver operating characteristic curves (AUCs). Stratum-Specific Likelihood Ratios (SSLRs) were computed to help produce individual-level predicted probabilities of being a case from screening scale scores in other samples. RESULTS The K10 was marginally better than the K6 in screening for CIDI/DSM-IV mood and anxiety disorders (K10 AUC: 0.90, 95%CI: 0.89-0.91 versus K6 AUC: 0.89, 95%CI: 0.88-0.90), while both were significantly better than the GHQ-12 (AUC: 0.80, 95%CI: 0.78-0.82). The SSLRs of the K10 and K6 were more informative in ruling in or out the target disorders than those of the GHQ-12 at both ends of the population spectrum. The K6 was more robust than the K10 to subsample variation. CONCLUSIONS While the K10 might outperform the K6 in screening for severe disorders, the K6 is preferred in screening for any DSM-IV mood or anxiety disorder because of its brevity and consistency across subsamples. Precision of individual-level prediction is greatly improved by using polychotomous rather than dichotomous classification.

Screening for Serious Mental Illness in the General Population with the K6 screening scale: Results from the WHO World Mental Health (WMH) Survey Initiative

Data are reported on the background and performance of the K6 screening scale for serious mental illness (SMI) in the World Health Organization (WHO) World Mental Health (WMH) surveys. The K6 is a six‐item scale developed to provide a brief valid screen for Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM‐IV) SMI based on the criteria in the US ADAMHA Reorganization Act. Although methodological studies have documented good K6 validity in a number of countries, optimal scoring rules have never been proposed. Such rules are presented here based on analysis of K6 data in nationally or regionally representative WMH surveys in 14 countries (combined N = 41,770 respondents). Twelve‐month prevalence of DSM‐IV SMI was assessed with the fully‐structured WHO Composite International Diagnostic Interview. Nested logistic regression analysis was used to generate estimates of the predicted probability of SMI for each respondent from K6 scores, taking into consideration the possibility of variable concordance as a function of respondent age, gender, education, and country. Concordance, assessed by calculating the area under the receiver operating characteristic curve, was generally substantial (median 0.83; range 0.76–0.89; inter‐quartile range 0.81–0.85). Based on this result, optimal scaling rules are presented for use by investigators working with the K6 scale in the countries studied. Copyright

The performance of the Japanese version of the K6 and K10 in the World Mental Health Survey Japan

Two new screening scales for psychological distress, the K6 and K10, have been developed using the item response theory and shown to outperform existing screeners in English. We developed their Japanese versions using the standard backtranslaton method and included them in the World Mental Health Survey Japan (WMH‐J), which is a psychiatric epidemiologic study conducted in seven communities across Japan with 2436 participants. The WMH‐J used the WMH Survey Initiative version of the Composite International Diagnostic Interview (CIDI) to assess the 30‐day Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM‐IV). Performance of the two screening scales in detecting DSM‐IV mood and anxiety disorders, as assessed by the areas under receiver operating characteristic curves (AUCs), was excellent, with values as high as 0.94 (95% confidence interval = 0.88 to 0.99) for K6 and 0.94 (0.88 to 0.995) for K10. Stratum‐specific likelihood ratios (SSLRs), which express screening test characteristics and can be used to produce individual‐level predicted probabilities of being a case from screening scale scores and pretest probabilities in other samples, were strikingly similar between the Japanese and the original versions. The Japanese versions of the K6 and K10 thus demonstrated screening performances essentially equivalent to those of the original English versions. Copyright

GRADE guidelines: 13. Preparing Summary of Findings tables and evidence profiles—continuous outcomes

Presenting continuous outcomes in Summary of Findings tables presents particular challenges to interpretation. When each study uses the same outcome measure, and the units of that measure are intuitively interpretable (e.g., duration of hospitalization, duration of symptoms), presenting differences in means is usually desirable. When the natural units of the outcome measure are not easily interpretable, choosing a threshold to create a binary outcome and presenting relative and absolute effects become a more attractive alternative. When studies use different measures of the same construct, calculating summary measures requires converting to the same units of measurement for each study. The longest standing and most widely used approach is to divide the difference in means in each study by its standard deviation and present pooled results in standard deviation units (standardized mean difference). Disadvantages of this approach include vulnerability to varying degrees of heterogeneity in the underlying populations and difficulties in interpretation. Alternatives include presenting results in the units of the most popular or interpretable measure, converting to dichotomous measures and presenting relative and absolute effects, presenting the ratio of the means of intervention and control groups, and presenting the results in minimally important difference units. We outline the merits and limitations of each alternative and provide guidance for meta-analysts and guideline developers.

Imputing response rates from means and standard deviations in meta-analyses

The principle of intention-to-treat analysis must be strictly applied to both individual randomized controlled trial and meta-analysis but, in doing so, would involve imputation of some missing data. There is little literature on how to perform this in the case of meta-analysis. For dichotomous outcome measures, one possible strategy is to carry out a sensitivity analysis based on the so-called best case/worst case analyses. For continuous outcomes, it may be possible to achieve this if we can dichotomise the continuous outcomes. Here, we empirically examined the appropriateness of converting continuous outcomes (expressed as mean±SD) into dichotomous outcomes (expressed as response rates) in four completed meta-analyses of depression and anxiety, assuming normal distribution of the continuous outcome measures. The agreement between the actually observed versus the imputed raw numbers of responders was indicated by an intraclass correlation coefficient of 0.97 (95% confidence interval 0.95–0.98). The pooled relative risks of the four meta-analyses based on the imputed values were virtually identical to those based on the actually observed values. When individual trials report the means±SDs of their outcome measures but fail to report response rates, it may therefore be possible to impute the response rates based on the means±SDs, and then submit the meta-analysis to worst case/best case analyses. This would allow a more robust and clinically interpretable estimation of the true, underlying treatment effect to be made.

Multicentre prospective study of perinatal depression in Japan: incidence and correlates of antenatal and postnatal depression

SummaryA multicentre study on the epidemiology of perinatal depression was conducted among Japanese women expecting the first baby (N = 290). The incidence rate of the onset of the DSM-III-R Major Depressive Episode during pregnancy (antenatal depression) and within 3 months after delivery (postnatal depression) were 5.6% and 5.0%, respectively. Women with antenatal depression were characterised by young age and negative attitude towards the current pregnancy, whereas women with postnatal depression were characterised by poor accommodation, dissatisfaction with sex of the newborn baby and with the emotional undermining. Antenatal depression was a major risk factor for postnatal depression.

Psychotherapy for depression among children and adolescents: a systematic review.

Objective:  To examine the clinical benefit, the harm and the cost‐effectiveness of psychotherapies in comparison with no treatment, waiting‐list controls, attention‐placebos, and treatment as usual in depressed youths.

Waiting list may be a nocebo condition in psychotherapy trials: a contribution from network meta‐analysis

Various control conditions have been employed in psychotherapy trials, but there is growing suspicion that they may lead to different effect size estimates. The present study aims to examine the differences among control conditions including waiting list (WL), no treatment (NT) and psychological placebo (PP).

Time to recurrence after recovery from major depressive episodes and its predictors.

BACKGROUND Depression is a remitting but recurring disease. However, there is a paucity of prospectively recorded data on the course of depression after recovery. METHOD A multi-centre prospective serial follow-up study of an inception cohort of hitherto untreated unipolar major depression (N = 95) for 6 years. We report the time to recurrence after recovery from the index depressive episode and their predictors. RESULTS The cumulative probability of remaining well without subthreshold symptoms was 57% (95% CI, 46 to 68%) at 1 year, 47% (95% CI, 36 to 58%) at 2 years and 35% (95% CI, 23 to 47%) at 5 years. The same without full relapse was 79% (95% CI, 70 to 88%) at 1 year, 70% (95% CI, 60 to 80%) at 2 years and 58% (95% CI, 46 to 70%) at 5 years. The median duration of well-interval from the end of the index episode to the beginning of the subthreshold episode was 19-0 months (95% CI, 2-4 to 35-7), and that to the end of the full episode was over 6 years. Residual symptoms at time of recovery predicted earlier recurrence. CONCLUSIONS The median length of the well-interval was much longer than previously reported in studies employing similar definitions but dealing with a more severe spectrum of patients. However, the sobering fact remains that less than half of the patients can expect to remain virtually symptom-free for 2 years or more after recovery from the depressive episode.

Comparative efficacy and tolerability of pharmacological treatments in the maintenance treatment of bipolar disorder: a systematic review and network meta-analysis

BACKGROUND Lithium is the established standard in the long-term treatment of bipolar disorder, but several new drugs have been assessed for this indication. We did a network meta-analysis to investigate the comparative efficacy and tolerability of available pharmacological treatment strategies for bipolar disorder. METHODS We systematically searched Embase, Medline, PreMedline, PsycINFO, and the Cochrane Central Register of Controlled Trials for randomised controlled trials published before June 28, 2013, that compared active treatments for bipolar disorder (or placebo), either as monotherapy or as add-on treatment, for at least 12 weeks. The primary outcomes were the number of participants with recurrence of any mood episode, and the number of participants who discontinued the trial because of adverse events. We assessed efficacy and tolerability of bipolar treatments using a random-effects network meta-analysis within a Bayesian framework. FINDINGS We screened 114 potentially eligible studies and identified 33 randomised controlled trials, published between 1970 and 2012, that examined 17 treatments for bipolar disorder (or placebo) in 6846 participants. Participants assigned to all assessed treatments had a significantly lower risk of any mood relapse or recurrence compared with placebo, except for those assigned to aripiprazole (risk ratio [RR] 0·62, 95% credible interval [CrI] 0·38-1·03), carbamazepine (RR 0·68, 0·44-1·06), imipramine (RR 0·95, 0·66-1·36), and paliperidone (RR 0·84, 0·56-1·24). Lamotrigine and placebo were significantly better tolerated than carbamazepine (lamotrigine, RR 5·24, 1·07-26·32; placebo, RR 3·60, 1·04-12·94), lithium (RR 3·76, 1·13-12·66; RR 2·58, 1·33-5·39), or lithium plus valproate (RR 5·95, 1·02-33·33; RR 4·09, 1·01-16·96). INTERPRETATION Although most of the drugs analysed were more efficacious than placebo and generally well tolerated, differences in the quality of evidence and the side-effect profiles should be taken into consideration by clinicians and patients. In view of the efficacy in prevention of both manic episode and depressive episode relapse or recurrence and the better quality of the supporting evidence, lithium should remain the first-line treatment when prescribing a relapse-prevention drug in patients with bipolar disorder, notwithstanding its tolerability profile. FUNDING None.