The weight that doesn't lift. Not sadness exactly — more like the volume knob on everything got turned down. Color, motivation, appetite, sleep. All muted.
Standard care typically starts with SSRIs or SNRIs — medications that adjust serotonin or norepinephrine levels. Often paired with cognitive behavioral therapy. These work for some people, partially for others, and not at all for roughly a third. Medication side effects — weight gain, sexual dysfunction, emotional blunting — drive many to stop treatment. For treatment-resistant cases, options narrow to electroconvulsive therapy, ketamine infusions, or TMS.
A 2015 randomized controlled trial by Efrati et al. treated patients with post-stroke depression using HBOT at 1.5 ATA. Patients receiving 40 sessions showed significant improvements in depression scores compared to controls, with gains persisting at follow-up. The researchers attributed improvements to enhanced neuroplasticity and perfusion in prefrontal regions.1
Liang et al. (2020) published a meta-analysis in Undersea and Hyperbaric Medicine examining HBOT as an adjunct for depression. Across multiple trials, HBOT groups showed statistically significant reductions in Hamilton Depression Rating Scale scores compared to controls. Mild HBOT protocols (1.5 ATA) showed comparable efficacy to higher-pressure protocols.2
A 2017 study by Boussi-Gross et al. demonstrated that HBOT at 1.5 ATA improved cerebral blood flow in brain regions associated with mood regulation — specifically the prefrontal cortex and anterior cingulate — in patients with persistent post-concussion symptoms including depression. SPECT imaging confirmed increased perfusion after treatment.3
Schiffer et al. (2009) conducted a controlled trial using near-infrared light (810 nm) applied to the forehead in patients with major depression and anxiety. A single treatment produced significant reductions in both Hamilton Depression and Hamilton Anxiety scores at two and four weeks post-treatment compared to sham. Published in Behavioural and Brain Functions.4
Cassano et al. (2016) published a study in Psychological Medicine examining transcranial photobiomodulation with 808 nm near-infrared light in treatment-resistant depression. Participants received twice-weekly sessions for eight weeks. The treatment group showed a 44% mean reduction in HAM-D scores, with several achieving full remission.5
Salehpour et al. (2019) reviewed the mechanisms of transcranial photobiomodulation in Molecular Neurobiology, finding that NIR light enhances mitochondrial cytochrome c oxidase activity, increases cerebral blood flow, and modulates neuroinflammation — all pathways implicated in depression.6