High-intensity interval training may reduce depressive symptoms in individuals with schizophrenia, putatively through improved VO(2)max: A randomized controlled trial
Question
Does supervised treadmill HIIT reduce depressive and other symptom dimensions in schizophrenia compared with an active video-game control, and is any depressive-symptom effect mediated by VO2max change?
Summary
In an observer-blinded randomized trial of outpatients with schizophrenia, 12 weeks of supervised treadmill HIIT reduced PANSS depressive symptoms more than supervised active video gaming, with the effect persisting at 4-month follow-up. Other psychotic symptom dimensions did not show clear between-group benefits, and mediation by VO2max was not confirmed.
Methodology
- Outpatients with DSM-5 schizophrenia.
- 82 participants.
- Treadmill walking/running.
- Work intervals: 4 min.
- Recovery: 3 min active recovery.
- Intensity: 85-95% HRmax during intervals; about 70% HRmax recovery.
- About 40 min.
- 2 sessions/week.
- 12 weeks.
- Observer-blinded randomized controlled trial
- PANSS depressed factor, CDSS, PANSS symptom dimensions, and VO2max mediation were tracked.
Outcomes
PANSS depressed
HIIT reduced PANSS depressive symptoms more than active video gaming, and the difference persisted at follow-up.
Group x time post estimate -1.03, SE .35, 95% CI -1.71 to -0.35, p=0.003, d=0.37.
CDSS
CDSS did not differ post-intervention but favored HIIT at follow-up.
Post p=0.320; follow-up p=0.032.
Other symptoms
PANSS total and most symptom dimensions did not show significant between-group improvement.
Positive symptoms showed a small follow-up reduction but no group difference; negative, disorganized, and excited factors were stable.
VO2max mediation
VO2max change correlated with depressive symptom change, but direct, indirect, and moderated mediation effects were not statistically significant.
Moderated mediation trend estimate 0.4, CI -1.188 to 0.087.
Insights
- Classic 4 x 4 treadmill HIIT may have depressive-symptom benefits in schizophrenia when supervised by sport and mental-health staff.
- Mental-health claims should be limited to depressive symptoms rather than broad schizophrenia symptom improvement.
Limitations
- Active comparator prevents inference versus no-treatment control
- Sample smaller than planned
- Mediation analysis underpowered
- No Bonferroni correction
- Add-on to antipsychotic medication and usual care
Safety
- No harm from HIIT was reported in the article.
- Participants with pregnancy or medical conditions incompatible with exercise were excluded.