Additional primary outcomes and secondary outcomes from studies focusing on prevention of depression and/or anxiety

In the preceding chapters, we reported the effectiveness results for the main outcomes of self-reported anxiety and depression. In this chapter, we report the additional outcomes from all studies focusing on anxiety, depression or anxiety and depression.

Additional primary outcomes

Self-reported psychological well-being

Of the 137 studies focused on preventing anxiety, depression, or both depression and anxiety, 15 reported an outcome of self-reported psychological well-being, life satisfaction or quality of life. Five studies reported measuring well-being using the Warwick–Edinburgh Mental Wellbeing Scale,124,126,127,132,133 seven studies reported a measure of life satisfaction124,131,159,181,187,203,239 and two studies reported a quality-of-life measure.129,235 One study reported a measure of social functioning206 and one used the Ryff Scales of Psychological Well-being.143 Planned NMAs by population and setting were not possible; data are reported by outcome measure and study in Table 10. From their model-based analysis, Calear et al.16 reported that there were no differences between interventions for school-led CBT and a waiting list (Cohen’s d –0.08, 95% CI –0.29 to 0.13) or between health service-led CBT and a waiting list (Cohen’s d –0.06, 95% CI –0.21 to 0.09). Using the data reported in the paper, we calculated the difference in mean change from baseline at post intervention, which suggested a small drop in well-being at post intervention. For each of the remaining 12 studies, summary intervention effects were compatible with both an increase and a decrease in well-being/life satisfaction.

Self-reported suicidal ideation, behaviour and self-harm

Author-defined suicidal ideation, behaviour or self-harm was referenced in 34 studies narratively or quantitatively. However, of these, the majority (n = 21) excluded participants reporting suicidal thoughts or behaviours and/or removed questions asking about suicide and self-harm from the baseline questionnaires. Some studies reported that the removal of questions was requested by participating schools or education authorities. Eleven studies reported that suicidal thoughts and behaviours were measured at baseline and that participants were referred to further services when necessary. However, nine did not then provide details on whether or not these students continued in the study, nor did they provide follow-up measures. The full details of these studies are reported in Appendix 7.

Seven studies reported participants experiencing suicidal thoughts or self-harm at post intervention.123,136,142,162,221,235,240 Details are reported in Table 11. Three studies were conducted in a universal secondary setting and formed a connected network via attention control. However, NMA model fit was suggestive of inconsistency, and combined results are not reported. Two studies were conducted in a targeted secondary setting, one in an indicated tertiary setting and one in a universal primary setting. There was no evidence to suggest that educational setting-based interventions to prevent anxiety and/or depression had an impact on suicidal ideation or thoughts of self-harm for CYP.

Inequalities in health

None of the included studies reported the impact of the intervention on inequalities in health;241 therefore, we conducted post hoc subgroup analyses on the basis of available data. Data had been extracted on participant characteristics, including SES, sex and ethnicity (see Chapter 2). Descriptions of SES, sex and ethnicity, as defined by study authors, are reported in Appendix 7. Owing to insufficient data, subgroup analyses could not be conducted by sex or ethnicity for any population or setting. Subgroup analyses for studies conducted in lower socioeconomic settings (as described by the author) are reported.

Eleven studies reported being conducted in lower SES settings, of which three were conducted in MICs118,122,189 and eight in HICs.139,140,152,156,157,196,208,210 Interventions evaluated in lower SES settings were CBT relative to usual curriculum, no intervention or a waiting list. Unfortunately, for the primary time point of post intervention, data were available for only seven studies conducted in HICs.139,140,152,156,157,196,208 The results suggest that, in the case of interventions in secondary school settings, those delivered in lower SES settings may be less effective than those delivered in higher/mixed SES settings in reducing self-reported symptoms of anxiety. However, owing to the number of studies available, it was necessary to conduct fixed-effects analyses for the lower SES subgroup. This was not observed for self-reported depression, although it is of interest that the SMD for CBT compared with usual curriculum in higher/mixed SES settings was –0.07 (95% CrI –0.20 to 0.06); in lower SES settings, the SMD was 0.04 (95% CrI –0.06 to 0.15).

Table 12 reports the subgroup analysis findings. There was no evidence of a difference by SES for either self-reported depression or anxiety in primary educational settings. However, for self-reported anxiety, the SMD of CBT compared with usual curriculum in higher/mixed SES settings was 0.15 (95% CrI –0.37 to 0.02); in lower SES settings, the SMD was 0.05 (95% CrI –0.08 to 0.18).

Combined depression and anxiety scores and other ‘internalising’ outcomes

As described in Chapter 1, Changes to protocol, clarifications and additional analyses, and Table 1, a post hoc decision was made to assess composite ‘internalising’ outcomes, for example outcome scales that reported combined anxiety and depression scores (such as total Depression, Anxiety and Stress Scale or RCADS scores) or ‘internalising’ subscales of broader psychological functioning measures such as the SDQ. Six studies reported an internalising outcome, with useable data at post intervention, and are reported in Table 13 by population and setting.119,123,163,171,216,219 Four studies in targeted secondary settings provided sufficient data for inclusion in a random-effects NMA.163,171,216,219 Model fit statistics suggested that a consistency model was reasonable; however, the posterior median between-study SD was indicative of substantial heterogeneity (τ 0.97, 95% CrI 0.03 to 9.03) and tended to the prior distribution [uniform(0,10)]. Consequently, we report only study-specific SMDs in Table 13.

A fixed-effects NMA was possible for a further two studies142,206 reporting a 12-month follow-up in a universal secondary setting, as they formed a connected network via usual curriculum.. However, there was no evidence that interventions based on CBT (SMD 0.03, 95% CrI –0.14 to 0.20) or CBT + IPT (SMD 0.01, 95% CrI –0.16 to 0.17) were more effective than usual curriculum for improving composite internalising outcomes at a 12-month follow-up.

Secondary outcomes

Acceptability and attendance

Intervention acceptability was defined by study authors. We anticipated considerable variability in the reporting of acceptability outcomes, but have combined them here under loose categories relating to (1) attitudes towards and satisfaction with intervention, (2) enjoyment and utility, and (3) attendance. Thirty-three studies reported a summary of acceptability of the intervention to study participants in terms of satisfaction or enjoyment and are summarised in Tables 14 and 15 by population and setting. Attendance data, as reported by authors, are reported in Appendix 7, Table 72.

Attitudes and satisfaction with intervention

Eight studies reported satisfaction with the intervention (see Table 14). Two studies120,137 reported an overall satisfaction outcome in a universal secondary setting. Both used Likert-type scales and suggested that students were highly satisfied with the interventions. In targeted secondary settings, five studies reported a satisfaction or attitude to ‘treatment’ measure.168,216,218,219,224 However, results were reported for the experimental/active intervention arms only, and not for controls. All reported that participants were satisfied with their intervention assignment. One study185 in a targeted tertiary setting reported satisfaction with intervention assignment, with a mean score of 4.0 (SD 0.47) on a five-point scale, suggesting that the majority of participants were satisfied with the intervention.

Intervention enjoyment and utility

Twenty-five studies reported enjoyment or utility of intervention. In universal secondary settings, 11 studies reported an acceptability outcome assessing enjoyment or usefulness of the intervention.123,127,132,133,135,139,142,197,202,206,207 However, only two studies reported comparative data for all arms of the study. Stallard et al.142 note that the control group intervention: ‘Usual PSHE [personal, social and health education] was rated more positively than both classroom-based CBT and attention control PSHE for liking [F 7.11, df (degrees of freedom) 2970; p < 0.01], usefulness (F 6.46, df 2966; p < 0.01) and relevance for their age (F 8.84, df 2963; p < 0.01).’ Merry et al.197 compared intervention arms on a five-point Likert scale, where five was the most positive score and one the most negative. The programmes were rated by the students as reasonably enjoyable. The control group intervention received slightly higher ratings than the experimental intervention for both enjoyment and utility (see Table 15). The majority of studies reported that participants enjoyed the intervention and found it useful. Only one study reported negative enjoyment and utility feedback from students207 (see Table 15).

In universal primary settings, eight studies reported some detail for enjoyment or usefulness of the intervention.145,146,150,156,158,159,210,212 Two studies evaluating the FRIENDS anxiety programme reported an acceptability outcome assessing enjoyment or usefulness.158,159 In Ruttledge et al.,158 68% of the children found the FRIENDS for Life programme ‘very useful’ or ‘somewhat useful’. Stallard et al.159 reported that 74% of participants enjoyed the intervention, 59% thought that it had been helpful and 62% would recommend it to a friend. Across all studies, results suggest that participants generally found the interventions enjoyable and useful (see Table 15).

Four studies reported enjoyment/utility in targeted secondary settings.162,217,221,227 Poppelaars et al.221 provided comparative data for two CBT-based interventions and concluded that acceptability was similar across the programmes. Woods and Jose227 conducted semistructured focus groups at the end of a CBT intervention, Adolescents Coping with Emotions. The focus groups were conducted in New Zealand, with the majority of participants being Maori and Pacific Islander students and identifying trust in the group as an important benefit of the intervention. In addition, some participants noted that the insight gained about thinking processes was useful. Participants liked the use of confectionery as a reward, and identified the games played and missing class as good aspects of the programme. However, they also felt that the intervention used out-of-date scenarios and that there was too much reading and writing involved in the sessions. Livheim et al.217 reported that most participants (91%) gave exclusively positive feedback on the evaluation of the acceptance and commitment therapy-based intervention and all reported that they would recommend it to a friend. The majority of students included in Cova et al.’s162 study enjoyed (71.6%) and found the CBT intervention useful (79%).

Two studies provided information on enjoyment in a targeted primary setting.115,116 Schoneveld et al.116 noted that children enjoyed both the experimental and control interventions equally (CBT vs. biofeedback). However, in an earlier trial, in which the control intervention was a commercially available computer game, children clearly preferred the control intervention.115

Attendance and dropouts from intervention

Only one study explicitly mentioned attendance as a proxy for acceptability of the intervention to participants. Congleton215 noted that attendance was excellent and that this reflected how much the students enjoyed the course and the importance of convenient timetabling.

Across all other studies, attendance was reported descriptively. Study-specific attendance details, as reported by trial author, are reported in Appendix 7.

Parent-reported child anxiety, depression or internalising outcomes

A post hoc decision was made to analyse parent-reported child anxiety, depression or internalising symptoms. For some of the studies, participants were considered too young for self-reported measures and parents were the primary respondents. In universal primary settings, five studies145,146,156,158,242 provided baseline and follow-up data on parent-reported child anxiety outcomes. From a random-effects NMA, there was no evidence that CBT-based interventions reduced parent-reported child anxiety symptoms relative to usual curriculum (SMD –0.10, 95% CrI –2.13 to 1.83).

Six studies115,116,176,177,181,182 provided both baseline and follow-up data to enable a NMA for targeted primary settings. There was no evidence that CBT-based interventions (SMD –0.43, 95% CrI –1.08 to 0.14), biofeedback (SMD –0.48, 95% CrI –1.76 to 0.72) or occupational therapy (SMD 0.05, 95% CrI –1.07 to 1.19) reduced parent-reported child anxiety symptoms relative to a waiting list.

Academic attainment

Seven studies reported academic attainment data.131,136,137,145,159,168,174 Various measures of attainment were used; we report study-specific results in Table 16. Across all studies, there was no evidence of an effect of intervention on academic outcomes.

Problem behaviours

Few studies reported problem behaviours, and those that did reported substance use. The following results are reported as per the original publications. In a universal secondary setting, Stallard et al.142 reported that there was evidence of a beneficial effect of CBT + IPT on cannabis use at 6 months (OR 0.56, 95% CI 0.38 to 0.82) and at 12 months (OR 0.70, 95% CI 0.48 to 0.93), but not on alcohol or ‘street drug’ use. In targeted secondary settings, Stice et al.224 reported that CBT reduced ‘substance use’ (F[6,674] 3.60; p = 0.002) relative to control and Topper et al.173 reported that there was ‘no significant difference’ between the intervention and control groups for binge drinking (Cohen’s d 0.22). In a tertiary/university setting, Reynolds et al.233 reported results from the Alcohol Use Disorders Identification Test (AUDIT) and concluded that there was ‘no significant difference’ observed between the intervention and control groups for alcohol consumption or alcohol problems, although they also report that:

. . . a significant interaction of the orientation group effect with the linear effect of time was found, suggesting differential change for the [intervention] and [control] groups across the three time points. The overall percentage of youth above the clinical cut off for the BATD [behavioural activation treatment for depression] group generally decreased over time.

Mental health-related stigma

During our initial PPI work, reducing the stigma associated with mental health problems was identified as an important outcome for young people. Only one study reported a mental health-related stigma outcome. In Perry et al.,136 stigma was measured using a nine-item subscale of the Depression Stigma Scale, an 18-item scale that assesses personal and perceived stigma towards depression, on which higher scores indicate greater stigma. At the immediate post-intervention time point, there was no evidence of a reduction in personal or perceived stigma in the SPARX (smart, positive, active, realistic, X-factor thoughts) computerised CBT group, compared with the attention control intervention (mean difference –0.50, 95% CI –2.90 to 1.90).