Efficacy of light therapy for a college student sample with non-seasonal subthreshold depression: An RCT study.
Study Goal
The researchers aimed to determine the efficacy of high- and low-intensity light therapy in treating non-seasonal subthreshold depression among college students.
Results Summary
Both high-intensity (5000 lux) and low-intensity (500 lux) light therapy were significantly more effective than the waiting-list control, with high-intensity therapy showing superior results (70.0% response rate vs. 42.0% for low-intensity and 19.0% for control). Remission rates followed a similar pattern (76.0%, 54.0%, and 19.0%, respectively).
Population
College students with non-seasonal subthreshold depression.
Effective Dosage
5000 lux (high-intensity) and 500 lux (low-intensity), frequency not specified.
Duration
8 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
high-intensity light therapy (LT-5000 lux) | decrease | Hamilton Depression Rating Scale (HAMD) score | college students with non-seasonal subthreshold depression | effect size [d] = 1.56, 95% CI: 1.15 to 1.98 | was significantly superior to | #1 |
low-intensity light therapy (LT-500 lux) | decrease | Hamilton Depression Rating Scale (HAMD) score | college students with non-seasonal subthreshold depression | effect size [d] = 0.84, 95% CI: 0.43 to 1.26 | was significantly superior to | #2 |
high-intensity light therapy (LT-5000 lux) | decrease | Hamilton Depression Rating Scale (HAMD) | college students with non-seasonal subthreshold depression | 70.0% of participants | achieved response by | #3 |
low-intensity light therapy (LT-500 lux) | decrease | Hamilton Depression Rating Scale (HAMD) | college students with non-seasonal subthreshold depression | 42.0% of participants | achieved response by | #4 |
waiting-list control condition (WLC) | decrease | Hamilton Depression Rating Scale (HAMD) | college students with non-seasonal subthreshold depression | 19.0% of participants | achieved response by | #5 |
high-intensity light therapy (LT-5000 lux) | decrease | Hamilton Depression Rating Scale (HAMD) | college students with non-seasonal subthreshold depression | 76.0% of participants | achieved remission by | #6 |
low-intensity light therapy (LT-500 lux) | decrease | Hamilton Depression Rating Scale (HAMD) | college students with non-seasonal subthreshold depression | 54.0% of participants | achieved remission by | #7 |
waiting-list control condition (WLC) | decrease | Hamilton Depression Rating Scale (HAMD) | college students with non-seasonal subthreshold depression | 19.0% of participants | achieved remission by | #8 |
light therapy, both at high- and low-intensity | decrease | non-seasonal subthreshold depression | college students | - | was efficacious in the treatment of | #9 |
high-intensity light therapy | increase | treatment efficacy | college students with non-seasonal subthreshold depression | by the end of an 8-week trial | was superior to | #10 |
BACKGROUND: Light therapy has been successfully used to treat seasonal and non-seasonal depression, but there is limited evidence for its efficacy in subthreshold depression. This study examines the efficacy of light therapy for symptoms of depression and anxiety in non-seasonal subthreshold depression. METHODS: College students with non-seasonal subthreshold depression were recruited. The participants were randomly allocated to one of the three conditions: high- (LT-5000 lux) and low-intensity (LT-500 lux) light therapy conditions and a waiting-list control condition (WLC). The primary outcome was Hamilton Depression Rating Scale (HAMD), and secondary outcomes were Beck Depression Inventory-II (BDI-II) and state anxiety inventory (SAI), which were assessed at baseline (Week 0), during the trial (Week 4), and after completion of the light therapy (Week 8). RESULTS: A total of 142 participants completed the trial. The LT-5000 (effect size [d] = 1.56, 95% CI: 1.15 to 1.98) and LT-500 conditions (d = 0.84, 95% CI: 0.43 to 1.26) were significantly superior to the WLC condition. For the LT-5000, LT-500, and WLC conditions by the end of the 8-week trial, a response on the HAMD was achieved by 70.0%, 42.0% and 19.0% of the participants, and remission was achieved by 76.0%, 54.0%, and 19.0%, respectively. LIMITATIONS: The subjects were not followed up regularly after completion of the trial. CONCLUSION: Light therapy, both at high- and low-intensity, was efficacious in the treatment of college students with non-seasonal subthreshold depression. High-intensity light therapy was superior to low-intensity light therapy by the end of an 8-week trial.