Odds of Seroquel working for all forms of schizophrenia - pretty damn good.   Expect to see relief from symptoms within a week or two.

Odds of Seroquel working for bipolar mania - OK, I guess.  There aren't many studies out there with Seroquel (quetiapine fumarate) as the only med used to treat bipolar disorder.  As far as the anecdotal evidence goes, people are reasonably satisfied with this med when it does work for bipolar mania.  It does do a good job at boosting an antidepressant's effect on the depression side of things and often can work as a stand-alone mood stabilizer, dealing with both mania and depression, despite being approved to treat only mania.   While I think Seroquel (quetiapine fumarate) is best suited as an add-on for bipolar disorder where sleep and/or anxiety and/or agitation are secondary issues, I'm just not too big on antipsychotics as monotherapy (i.e. the only med you take) for bipolar disorder.  But it does alone work to stabilize a lot of people.  If anticonvulsants don't do it for you, Seroquel can be your med in the long run.

Odds of Seroquel working for panic / anxiety disorders - really good.  Atypical antipsychotics aren't front-line meds for panic / anxiety, but they work really well for some forms of the disorders.  Since Seroquel (quetiapine fumarate) is the mildest of the atypical antipsychotics, and is the best at helping you sleep, it's probably the best one in the class to try first for panic / anxiety.  Barring any other symptoms that indicate trying one of the others, of course.

Odds of Seroquel working for sleep disorders - dude, if you can't sleep, ask your doctor about Seroquel (quetiapine fumarate).  Seriously.  AstraZeneca really needs to be doing some heavy clinical trials for a rebranded version to compete with Ambien as a less messed-up sleep aid for the mentally interesting.  Not that they will, it's just what they should be doing.  Seroquel isn't right for everyone (e.g. people with seizure disorders), but it sure is hell a lot better, and more effective, than other sleep aids for us nut jobs.

Odds of Seroquel working for depression - apparently it's pretty good for depression, but I can't tell yet if it's better for bipolar depression than unipolar depression.  It looks like it's OK for unipolar depression, but better for bipolar, schizoaffective and schizophrenic depression.

Now for the details as to how I arrived at the above odds.  Mostly it's from anecdotal evidence gathered from various online support groups I monitor, user ratings and comments at Remedy Find, experiences people send to me via e-mail and summaries of efficacy from the books in the references at the end of this page.  Additionally there are these trials and studies from the PI sheet and that I found through Pub Med:

For schizophrenia efficacy was established in 3 short-term (6 week) controlled trials of well over 1,200 people with schizophrenia. In one trial they used Haldol (haloperidol) as a comparative treatment,  but it was inadequate to provide a reliable and valid comparison data.  Poor Haldol.  I'd really like to know what its inadequacy issues were all about.  Anyway, in the three placebo-controlled six-week trials 50, 75, 150, 300, 450, 500, 600, and 750mg a day were tried, usually split over three times a day.  Although two and four times a day dosing was tried as well.  50mg a day didn't do much.  300-500mg a day taken three times a day worked the best.  This is where they found that Seroquel (quetiapine) works better on people under 40 than people over 40.

For acute efficacy was established in 3 placebo-controlled trials of a little of 750 bipolar people.  These trials included patients with or without psychotic features and excluded patients with rapid cycling and mixed episodes. Two were Seroquel alone, one, lasting all of 3 weeks, was using it along with lithium or Depakote (divalproex sodium).  Dosages were 400-800mg a day for all three trials.  It doesn't state in the PI sheet what the optimal dosage was from the trials, just that a enough people got better enough to warrant FDA approval.

Oh, and there was a fourth trial of 200 people.  The wonder drug Placebo did better than Seroquel in that one.  One of these days I have to buy some stock in the company that makes Placebo.

See the page on a drugs' efficacy for an explanation of the tests used to evaluate if a medication is any good or not.

As usual, there are no hard numbers in the PI sheet for what is considered "superior" to placebo on these various tests.

As usual with atypical antipsychotics, I'm none too happy with the bipolar trials.  Although they had a decent amount of people (300, 299, 170  and 200 people) they were still pretty short (six weeks for monotherapy, three weeks when combined with lithium or Depakote).   And only the  Young Mania Rating Scale  was used.  So the people in the experimental group started at 400mg a day (100mg higher than what was shown to be effective for schizophrenia) and got some vague improvement on the Young Mania Rating Scale.

But as shown by the test that Seroquel failed,

If you want to get a better idea how well Seroquel (quetiapine fumarate) stacks up against other meds, then dive into some of the other studies.

Seroquel for Bipolar

Seroquel for Schizophrenia

Seroquel for Other Disorders

So, what does that mean in English?  Well excessive dopamine in certain parts of the brain is one popular hypothesis behind the symptoms of schizophrenia.  There's also evidence that working on the muscarinic receptors makes a big difference as well.  But since Seroquel doesn't do the muscarine thing that's a good-news / bad-news deal  The good-news is that the anticholinergic side effects - dry mouth, nausea, dizziness, aren't as big a deal and don't last as long with Seroquel as compared with Zyprexa (olanzapine).  The bad news is that Seroquel doesn't work as well with some some forms (mostly the atypical) of schizophrenia or ultradian rapid cycling bipolar disorder because of not hitting the muscarinic receptors. 

For bipolar disorder, anyone who lives in Bipolarland can tell you about getting manic from having their brain soak in serotonin for too long from an SSRI.  Or perhaps the same thing happened from too long of a soak in norepinephrine and dopamine from Wellbutrin. 

One reason why Seroquel is getting more and more popular for bipolar and schizoaffective disorders is that Seroquel targets your serotonin receptors more than your dopamine receptors (Julien A Primer of Drug Action and Stahl Essential Psychopharmacology of Antipsychotics and Mood Stabilizers).

Since it hits your H₁ histamine receptor hard, Seroquel (quetiapine fumarate) is the official antipsychotic of sleepy-bye land.

As is typical in the world of psychopharmacology, no one uses a consistent scale in rating anything (I mean, no one can even agree as to what PI stands for!).  The good news is that Seroquel was measured using the IC50 scale, so its effects can be measured against antidepressants.  The bad news is you can't easily measure its potency relative to Risperdal or Zyprexa.  Grrrrrr.  The consensus in the trenches is that Seroquel is the mildest of the atypical antipsychotics.

Seroquel's Half-Life: An average of six hours. 

Days to Reach a Steady State: About two days.
When you're fully saturated with the medication and less prone to peaks and valleys of effects. You still might have peaks of effect after taking many meds, but with a lot of the meds you'll have fewer valleys after this point. In theory anyway.