When we experience depression,we experience a lack of physical and emotional grounding. Breath is shallow ,shoulders are rounded, head is lowered and spine is colapsed.
Anixiety most often is paired up with depression and the practitioner can find he or she has trouble being fully present on the mat and in the physical body with awarness while practicing.
Supine positions where the heart center opens are recommended. Working with Asanas that are grounding calming and uplifting and focusing on body postures first then on the breath may help. Inversions foster mental and emotional stability. Downward Facing Dog as well as Standing Forward Bends are great for this purpose.
It is desirable to keep the practicioners mind engaged while practicing Yoga and avoid leaving them wonder into thinking or feeling lonely or sad. Some students will keep their eyes open in savasana or very relaxing pasive poses.
Mantra meditation is useful as a mental suport for those strugelling with anxiety or depression. Part of the focus will shift outward to prevent the practitioner falling into thoughts and feelings.
Fast breathing techiniques could come in hand in the begining and the end of classes.
When feelings of Sadness or depresion arise, try to focuse on something or someone you are grateful for. No matter how bad things are each of us have reasons to feel gratitude. Gratitude and Apreciation practices can be introduces in the bedinning, during and at the end of class.