how do I reconcile ongoing psychiatric treatment with Christianity, when psychiatry (and psychology) are so decidedly anti-Christian in their worldview?
I'm a psychologist myself (well not yet, but God willing I might graduate next year) and a mental health patient: combined personality disorder, including borderline, avoidant, narcissistic and histrionic personality disorder (so I'm seriously a bad person


and depressions/ anxiety as a result of being self destructive and ruining my life.
What kind of diagnosis I get does somewhat depend on who is conducting the diagnostics, and on my mood of the moment (I don't always behave avoidant or narcissistic or borderline-ish, so some doctors or psychologists may find those diagnoses not justified). So it's subjective like it is in your case, Christ_empowered.
Diagnostics is always a bit subjective, although the makers of the diagnostical manuals try to make the different kinds of disorders as distinct and clear as possible and conduct large tests for the objectivity of diagnoses. However, humans aren't perfect, neither the ones diagnosing you, nor the patients themselves. Some (actually quite a number of them, myself included) are such weird cases they can't seem to fit into the categories at our disposal. Dang those uncooperative patients. :p (Just kidding.)
Maybe it helps to keep in mind that most of the mental health diagnoses aren't causal explanations of what you have, they are just descriptions of the symptoms you show. In physical medicine many diagnoses depend on the cause of the illness. In mental health (at least in many areas of it) the symptoms you show is the disorder you have. If your symptoms change over time, then the name they give your disorder changes, although the reason behind it may still be the same and although non of the shrinks made a mistake. That's probably difficult to grasp as a person affected by it. But that's just how the diagnostic system works.
Sorry for that long side track. I was just trying to help you understand why you got so many different labels for your ailment. Maybe you actually did show signs of schizophrenia when you were younger but show signs of a Bipolar disorder now and both diagnoses were correct.
My mental health condition is a bit different from schizophrenia or bipolar disorder, because I "learned" my destructive and selfish behaviour during the years past and I can hope to unlearn it, or at least so much of it that I may lead a normal life some time. It's a rough road though. But bipolar disorders and schizophrenia both seem to have a big biological component, they are more like an illness of your brain itself.
I can reconcile ongoing treatment with my faith because I don't perceive secular mental health to be "anti-christian". It's just neutral to religion. A good shrink can see your faith as a resource for your recovery, even if the shrink him/herself does not believe in God. Even non-religious shrinks will admit that religion gives people a sense of hope, meaning and purpose, access to supportive religious communities, and that prayer/ meditation often has a calming and relaxing effect. Because those things have been proven by science. Although it's the job of a shrink to question your worldview (because often we have ideas in our head the make or keep us sick) and thus they may have to question some of your faith, a good shrink can spot a healthy faith and would work with it instead against it. Thinking about it there's 3 shrinks and 1 psychiatrist in my church, plus several psychologists who work in an area other than mental health. Plus a number of people (including one of our pastors) who I know are mental patients or have been in their past. So psychiatry and psychology are not necessarily an anti-christian thing altogether. Many people seem to be able to reconcile it.
Maybe you can look at it as a sort of a chronic disease. Like diabetes or asthma or Crohn's disease. If a christian suffering from diabetes sees a doctor to cope with their illness nobody would see a need to reconcile that with their faith, because because diabetes is a condition that just needs some treatment in order to live a good life, and even christians can accept that.
Same with mental health.
Something is wrong with your body (in particular your neurological processes) and it needs some help to perform well enough for a normal life. So why not take the help of modern medicine? In the new testament neither Jesus, nor any of the apostles ever spoke negatively about doctors. Jesus even compared Himself to a doctor, showing how He was having a positive attribute towards the medical profession in general. There are plants growing wildely out there in nature (for example St. John's Wort) that have a medically proven effect alleviating depressions and improving our mood. So if you believe nature was purposefully created by God then you can assume God has made those plants because He's okay with us curing mental health issues through chemical intervention.
Just like with other chronic diseases you may have to keep taking meds for the rest of your life. You are absolutely right trying to keep the meds to a minimum. There is absolutely no use in overmedication. To the contrary, it may be very harmfull to your mind and body. But keep in mind that going off of all meds may cause a relapse that can be much more damaging to your recovery then taking meds for a prolonged time. As with all things in life wisdom and balance are required.
There are some cases of people that have a bipolar condition who went off most of their meds or almost all of it. They have learned to take very good care of themselves and regulate their mood swings in a non-medical way. You may have to go through a cognitive behavioural therapy (much less invasive than psychiatry!!) to learn things like relaxation, stress resistance, emotional self-awareness and regulation, and so on. Also, a chrisitan counsellor who is trained in dealing with psychiatric conditions may help you use prayer and scripture reading for coping with your symptoms.
The amount of meds you need does depend on environmental, social and behavioural factors, so there is hope you can greatly reduce the meds you take, but it'd take time and a learning process and maybe life changes to get there. That's where God, family, church and faith may play a great and positive role helping you heal and giving you the resources and love and support so you may need less and less medication over the years to come.
Sorry for the lengthy post.

I totally need to learn to be brief.