I personally experienced 6 months of being flat on my back with sciatica so i know what it is like to live with this type of debilitating symptom. I have made a full recovery. In short the problem is a combination of muscular, neurological and psychological. So stress can have a major affect and be the underlying cause of the symptom.
When you consider that the brain communicates with every part of the physical body when you stress it disrupts the communication between the area of the brain the issues are being stored and in your case the sciatica nerve.
Bioenergy healing www.bioenergyhealing.org.uk helped to overcome all my spinal conditions. It can release the memory pattern on both psychological level as well as cellular level i.e nerve.