The Effects of High-dose Vitamin B6 on Depression and Anxiety Symptoms

The primary question this trial aims to answer is: \- Compared to placebo, in people experiencing depression and anxiety symptoms, does high-dose Vitamin B6 supplementation change the excitation/inhibition balance towards inhibition as measured using electroencephalography (EEG)? Secondary research questions are: * Compared to placebo, does high-dose Vitamin B6 supplementation reduce symptoms of depression and anxiety? * Do individuals with lower Vitamin B6 levels at baseline, as measured in blood plasma, show a larger effect of high dose Vitamin B6 on the EEG measures or symptoms? * Compared to placebo, does high-dose Vitamin B6 intervention lead to an increase in hand grip strength? This is a possibility suggested to us by our prvious finding of reduced self reported 'postural disorder' by Vitamin B6 (Field et al., 2024), and by existing literature about the role of Vitamin B6 in muscle function.