Do you think it acceptable for a witch to use mind altering medically prescribed chemicals to reduce depression or is it a sign of mental weakness?

I think any hurdle that can be overcome should be. If a witch feels depression is holding her back then I see no reason at all why she should deny herself medication that will help her feel better and help her to concentrate her mind on what she wants to do. To my mind it makes sense to do whatever needs to be done, I don't see taking medication as mental weakness, just good practical common sense.
Having said that, there are many things that can be used either by themselves or as a compliment for medication to reduce depression. I would never overlook the impact of meditation, shielding, crystal healing, tarot guidance etc. Finding the balance between spiritual practises and medical help can often be the key breakthrough people need to successfully beat back depression. I wouldn't call a person who chose to rely solely on medication mentally weak but I would perhaps consider them a little hasty to reject taking a more holistic view and treating the cause as well as the symptoms. 
Fundamentally, your doctor will guide you. There is a reason they spend so long in medical school, they know what they are talking about. If a doctor suggests a course of anti depressants, it may well be the best solution.  But there is nothing to stop you improving your spiritual health as well as you are then giving yourself the best chance of that depression not returning.

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