Key Research Findings

Bright light therapy has become an accepted treatment for seasonal affective disorder (SAD), but there have been few studies about adverse effects from using this treatment. 2 conducted a study to examine the frequency of adverse effects of bright light treatment for SAD.

A double-blind random-ordered comparison of the effects of placebo and 5-hydroxytryptophan (200 mg, orally) in ten depressed patients with seasonal affective disorder (SAD) and ten controls, 1 disclosed slightly but significantly higher basal levels of serum prolactin and a trend toward higher basal levels of serum cortisol in the patients with SAD compared with controls. After administration of 5-HTP, the cortisol level significantly increased and the prolactin level significantly decreased in both patients and controls. No differences in the melatonin level, growth hormone level, blood pressure, or pulse rate and no side effects were noted between patients and controls in the two study conditions; the timing of basal and 5-hydroxytryptophan-stimulated hormonal secretions was similar for both groups.

Bright light therapy has been established for treatment of winter depression, or seasonal affective disorder (SAD). Analysis of side effects most often have focused on a narrow set of suspected symptoms, based on clinical observation (e.g. headache, eyestrain, nausea, insomnia, and hyperactivity). broadens the purview to a set of 88 physical and subjective symptoms that might emerge, remit, or remain unchanged relative to baseline, thus reducing bias toward assessment of presumed side effects.

Reasons for Side Effects

Side effects from bright light therapy may be caused by several factors, including the intensity of light, duration of exposure, and individual sensitivity. 1 suggests that neuroendocrine responses, such as decreased prolactin levels and increased cortisol levels, may contribute to side effects in SAD patients.

Common Side Effects

Headache

Headache is one of the common side effects of bright light therapy, according to 2 and . Headaches are more common in people who are sensitive to light or who use light therapy for a long period of time.

Eyestrain

Eyestrain is another common side effect reported in 2 and . Eyestrain occurs as a result of looking at bright light for a long time.

Nausea

Nausea is also reported as a side effect in 2 and . Nausea is more common in people who are sensitive to light or who use light therapy for a long period of time.

Insomnia

Insomnia is also reported as a side effect in 2 and . Insomnia may occur when light therapy is received before bedtime.

Hyperactivity

Hyperactivity is also reported as a side effect in 2 and . Hyperactivity may occur when light therapy is received during the day.

Managing Side Effects

Headache Management

If you experience headaches, you can reduce the intensity of the light, shorten the duration of exposure, or take over-the-counter pain relievers.

Eyestrain Management

If you experience eyestrain, take frequent breaks during light therapy. You can also use eye drops to relieve eye strain.

Nausea Management

If you experience nausea, you can try receiving light therapy after meals. You can also take an over-the-counter anti-nausea medication.

Insomnia Management

If you experience insomnia, make sure to finish light therapy at least 2 hours before bedtime.

Hyperactivity Management

If you experience hyperactivity, try receiving light therapy in the morning.

Comparison Across Studies

Commonalities

All three studies concluded that bright light therapy is effective for treating SAD. They also reported side effects such as headache, eyestrain, nausea, insomnia, and hyperactivity.

Differences

1 suggests that bright light therapy may affect the neuroendocrine system in SAD patients. This study examined decreased prolactin levels and increased cortisol levels.

conducted a comprehensive analysis of side effects, examining 88 physical and subjective symptoms.

Practical Implications

While bright light therapy is an effective treatment for SAD, it is important to be aware of the potential risks of side effects. To minimize side effects, consult with your doctor before starting light therapy to determine the appropriate intensity, duration, and schedule of light therapy.

Limitations of Current Research

Research on side effects of bright light therapy is still limited and more research is needed. In particular, more information is needed on long-term side effects and side effects in specific populations.

Future Research Directions

Future research should investigate the differences in side effects with different intensities, durations, and schedules of light therapy. Additionally, side effects in specific populations (e.g. elderly, children, pregnant or lactating women) should be investigated.

Conclusion

Bright light therapy is an effective treatment for SAD, but it is important to be aware of the potential risks of side effects. To minimize side effects, consult with your doctor before starting light therapy to determine the appropriate intensity, duration, and schedule of light therapy. Further research on side effects of bright light therapy is needed in the future.