## 3 Observations and Analysis
### Methodological Characteristics of Selected Studies  
Table 4 shows the experimental methodologies that were employed in the studies. In total, 22 different experimental methodologies were used, which included the following: double-blind randomized controlled trial, randomized controlled trial, randomized controlled trial with a blinded outcome assessor, randomized crossover trial, controlled trial, single-blinded randomized controlled trial, two-arm open randomized controlled trial, non-randomized feasibility and pilot trial, non-randomized controlled trial, unblinded two-phased trial, parallel-group randomized non-inferiority trial, single-blind randomized controlled trial, case study, non-randomized pilot trial, pilot randomized controlled trial, two-phase randomized controlled trial, randomized controlled non-inferiority trial, proof-of-concept trial, unblinded parallel-group randomized trial, pilot trial, and single-blinded randomized control trial. There were 17 studies (45.9%) that had some form of control groups to compare their findings with, while 20 (54.1%) involved some form of randomization in the subject allocation to the experiment group, indicating that both techniques were favored by the authors of the reviewed studies more than others, such as pilot studies or case studies. Table 4 also shows the evaluation technique or measures that were used in the studies in different combinations to assess the impact of the CSG interventions. There were 30 different evaluation technique/measures among the studies, which included analysis of covariance, depression anxiety and stress scale (DASS-21), clinical global impressions scale (CGI), Spence children's anxiety scale (SCAS), state-trait anger expression inventory--child and adolescent (STAXi-CA), fMRI during a stroup/flanker task, hospital anxiety and depression scale (HADS), visual analog scales (VAS), post-traumatic diagnostic scale (PDS), state-trait anxiety inventory, medication adherence rating scale (MARS), heart rate, patient health questionnaire (PHQ-9), behavioral approach test (BAT), visual analogue scale assessment (VAS-A), state-trait anxiety inventory for children (STAIC), Spence children's anxiety scale (SCAS-C), geriatric depression scale (GDS), beck depression inventory (BDI), novel interview schedule, novel interview schedule, acrophobia questionnaire, Spence children's anxiety scale (SCAS), Hamilton depression rating scale (HAM-D), acceptability score, profile of mood state second edition (POMS2), depressive symptoms (QIDS), [PERSON]'s picture test', and Spence children's anxiety scale parent version (SCAS-P) and child version (SCAS-C). The most frequently used technique was Spence children's anxiety scale (SCAS) in nine studies for anxiety and its comorbidities [66; 67; 68; 35; 69; 62; 63; 64; 65; 64; 66; 35] followed by patient health questionnaire (PHQ-9) in six studies for depression and its comorbidities [37; 44; 54; 56; 66; 68]. There were 12 data collection techniques employed which were mostly similar to each other. These included real-time with remote servers and some post-game questionnaires, real-time through the game, pre- and some post-game questionnaires, observation, pre- and some post-game questionnaires, observation, during a game session by pausing gameplay and some post-game questionnaires, pre- and post-game questionnaires, pre- and post-game questionnaires and brains scans during gameplay, post-game questionnaires post-game questionnaires and MRI scans, pre- and post-game and follow-up questionnaires, video capture of player reactions as well as pre- and post-game questionnaires, post-game questionnaire and during game observation, pre- and post-game questionnaires accompanied with interviews. Interestingly, the most frequently used data collection technique involved follow-up questionnaires (35%) indicating that a fair number of studies reviewed rigorous investigation of the effectiveness of the application of serious games for affective disorders.