Anxiety & Depression
How does RLT help?
A recent review of all existing studies with red/near-infrared light therapy (RLT) on anxiety and depression disorders demonstrates that RLT offers a "promising treatment" for major depressive disorder, anxiety, suicidal ideation, traumatic brain injury and post-traumatic stress disorder.
Some of the proposed mechanisms by which RLT can help are by boosting mitochondrial health, improving blood flow to the brain, reducing inflammation and reactive oxygen species, enhancing levels of serotonin and decreasing levels of nitric oxide.
How does this improve my
health & wellness?
Neural tissue is very rich in mitochondria, which contains cytochrome c oxidase (CCO). It so happens that CCO can readily absorb light in the red/NIR light spectrum and it is by this mechanism that RLT plays such a vital role in overall mitochondrial health and efficiency. Since the brain is so dense with mitochondria, it has enormous potential to achieve therapeutic benefits via RLT.
Research indicates that individuals with depressive symptoms tend to have abnormal blood flow to their prefrontal cortex (front of the brain). RLT may help increase cerebral blood flow secondary to the increased vasodilation that occurs after the release of nitric oxide (NO). NO is released when red/NIR light is absorbed by the CCO in the mitochondria.
For example, studies demonstrate that RLT applied to the forehead increases prefrontal cortical blood flow and metabolism, decreases inflammation, stimulates neurogenesis, and reduces depression scores among patients with major depressive disorder.
Serotonin (5-HT) also plays a vital role in the pathology of anxiety, mood disorders, and depression. The monoamine-deficiency hypothesis proposes that depression results as a consequence of an imbalance and deficiency of depression-dependent monoamine neurotransmitters including 5-HT, dopamine, & noradrenaline in the central nervous system (CNS).
Nitric oxide (NO) is another neurotransmitter that plays a pivotal role with depression, anxiety, and cognition. Prolonged and elevated production of NO has neurotoxic effects and may contribute to tissue damage. In addition, the decreased levels of 5-HT in the CNS are considered to be associated with an increase in NO levels.
The transcranial photobiomodulation (t-PBM) technique is a promising approach for the treatment of a wide range of neuropsychiatric disorders, including disorders characterized by poor regulation of emotion such as major depressive disorder (MDD). The t-PBM technique directs light, typically NIR, to the brain through the skull. NIR is utilized because it penetrates deeper compared to red light.
Currently, there are a wide range of t-PBM clinical trials, including those targeting MDD, generalized anxiety disorder, dementia, traumatic brain injury and post-traumatic stress disorder (PTSD).
What does the research show?
"NIR t-PBM reversed the anxiety and depression status caused by chronic stress that was probably linked to increased 5-HT (serotonin) and decreased NO (nitric oxide) levels in the both prefrontal cortex and hippocampal areas."
Eshaghi, Emad & Sadigh-Eteghad, Saeed & Mohaddes, Gisou & Rasta, Seyed. (2019). Transcranial photobiomodulation prevents anxiety and depression via changing serotonin and nitric oxide levels in brain of depression model mice: A study of three different doses of 810 nm laser. Lasers in Surgery and Medicine. 10.1002/lsm.23082.
"Using transcranial LED therapy, a significant decrease in PTSD scores and depression levels have been reported after 1 week of treatment, while result of 2 months post-treatment did not show an overall linear trend response."
Naeser MA, Zafonte R, Krengel MH, Martin PI, Frazier J, Hamblin MR, Knight JA, Meehan WP III et al (2014) Significant improvements in cognitive performance post-transcra- nial, red/near-infrared light-emitting diode treatments in chronic, mild traumatic brain injury: Open-protocol study. J Neurotrauma 31(11):1008–1017
The first study in MDD (major depressive disorder) patients showed that a single session of LED therapy alleviated depression and anxiety symptoms (Hamilton scales) at 2 weeks post-irradiation. At the end of four weeks, 6 out of 10 patients experienced a remission in their depression and 7 out of 10 patients experienced remission of their anxiety.
Schiffer F, Johnston AL, Ravichandran C, Polcari A, Teicher MH, Webb RH, Hamblin MR (2009) Psychological benefits 2 and 4 weeks after a single treatment with near infrared light to the fore- head: A pilot study of 10 patients with major depression and anx- iety. Behav Brain Funct 5(1):46.
"The proposed illumination strategies inform the design of t-PBM systems likely to improve brain emotion regulation, both in clinical research and practice.”
Paolo Cassano, Anh Phong Tran, Husam Katnani, Benjamin S. Bleier, Michael R. Hamblin, Yaoshen Yuan, Qianqian Fang, “Selective photobiomodulation for emotion regulation: model-based dosimetry study,” Neurophoton. 6(1), 015004 (2019), doi: 10.1117/1.NPh.6.1.015004.
**While the current scientific research seems to indicate many positive benefits of RLT in relation to anxiety and depressive disorders, there is still an appreciable necessity for more extensive research to be conducted, including double-blind RCT (randomized controlled trials), to provide a more comprehensive, robust overview that will further elucidate the optimal parameters and appropriate uses of RLT, which will ultimately lead the most safe and efficacious uses for individuals dealing with anxiety and depressive disorders.
Suggested use of RLT for anxiety & depression
5 - 7x/week
Optimal treatment time:
8 - 12 min @ 6 - 12"
(to penetrate deeper through skull
and target the brain tissue)
A study by Disner et al. revealed that t-PBM delivered to the right forehead was more effective for alleviation of depression symptoms than PBM to the left forehead.
*For optimal results, we recommend no more than 15 - 20 minutes of total treatment time per day