Depression is when someone feels despair and hopelessness. This can be caused partly by regret over the past and present, magnifying previous failures and having no hope in the future. By putting your trust elsewhere you can almost detach yourself from these. If you start believing that there is hope in the future, understanding that past failures aren't the defining moments of your life etc can help dramatically to lift depression. People who are religious are proven to be 'happier' overall.

Ignorance is bliss but can cause many problems.

   What Allah and prayers has got to do with depression. Ya ya when anything people don't understand then refer them to Allah, what a load of -----h

   To Allah we belong and to Him is truly our return.

The poor man was obviously in advanced depression, may Allah forgive him. Prayers can of course work miracles but maybe he also needed to increase his tawakkul.

If we trust more in Allah then we blame ourselves less as we realise we don't really have much control over things, which in turn will minimize most causes of depression. But it ain't easy!

This is a good read for anyone interested. http://yunuspatel.co.za/downloads/Tafweez.pdf