TABLE 2.
Efficiency analyses, mixed-effects model, and intention-to-treat protocol, best fit models.
| Parameter | Description of change | Effects | Estimates (SE) | 95% CI | P-value | |
| Overall symptoms | PANSS total† | Reduction in both groups, but no group difference | Baseline | 36.32 (1.82) | (32.76, 39.89) | |
| Post-intervention | −3.29 (1.39) | (−6.01, −0.58) | 0.018 | |||
| Follow up | −4.16 (1.52) | (−7.14, −1.18) | 0.006 | |||
|
| ||||||
| Psychotic and non-psychotic symptoms | PANSS positive‡ | Reduction in both groups, but no group difference | Baseline | 5.64 (0.45) | (4.76, 6.52) | |
| Post-intervention | −0.51 (0.35) | (−1.20, 0.19) | 0.153 | |||
| Follow up | −1.09 (0.39) | (−1.85, −0.34) | 0.005 | |||
|
|
||||||
| PANSS negative ‡ | Stability in both groups | Baseline, post-intervention and follow-up | 9.05 (0.70) | (7.68, 10.43) | ||
|
|
||||||
| PANSS Disorganized‡ | Stability in both groups | Baseline, post-intervention and follow-up | 4.51 (0.30) | (3.93, 5.09) | ||
|
|
||||||
| PANSS Excited‡ | Stability in both groups | Baseline, post-intervention and follow-up | 1.87 (0.20) | (1.47, 2.26) | ||
|
|
||||||
| PANSS Depressed‡ | No change in AVG, significant reduction in HIIT compared to AVG at post-intervention, relative to baseline, persisting to follow-up | Baseline | 3.97 (0.28) | (3.41, 4.52) | ||
| Group × time§ | −1.03 (0.35) | (−1.71, −0.35) | 0.003 | |||
|
| ||||||
| Depressive symptoms | CDSS¶ |
No change in AVG, significant reduction in HIIT compared to AVG at follow-up, relative to baseline | Baseline | 1.12 (0.8) | (0.95, 1.28) | |
| Group × time at post-intervention | −0.13 (0.13) | (−0.39, 0.13) | 0.320 | |||
| Group × time at follow-up | −0.31 (0.14) | − 0.59, −0.03) | 0.032 | |||
|
| ||||||
| Cardio- respiratory fitness | VO2max†† | No change in HIIT or AVG at post-intervention. Reduction in HIIT compared to AVG at follow-up relative to baseline | Baseline and post-intervention | 29.91 (1.16) | (27.64, 32.19) | |
| Group × time at follow-up | −2.37 (0.74) | (−3.82, −0.92) | 0.001 | |||
SE, Standard error; CI, confidence level. Group 0 = AVG, 1 = HIIT. Post-intervention and follow-up are both compared to baseline.
†The Positive And Negative Syndrome Scale, ratio version (item scale shifted to 0–6). Total = Sum of all 30 items (0–180p).
‡PANSS symptom factors from the five-factor model by Wallwork et al. (33), for more details see Table 1.
§Post-intervention and follow-up were merged into a single time point (time after baseline) as no changes were detected in either group between these two time points.
¶Calgary Depression Scale for Schizophrenia, transformed by adding 1 to facilitate logarithmic transformation, and log-transformed (ln).
††Maximum oxygen uptake (missing HIIT = 1).
Non-significant effects are taken out of the models. Supplementary Table 1 shows the more saturated models, including both time and interaction effects of time and group.