I don’t know if this answers your question, but it appears that some people who may look depressed are actually bipolar. I don’t know if they develop into bipolar, or if they get correctly re-diagnosed.
Fromhere, a checklist for soft bipolar/bipolar spectrum disorder (that is to say, bipolar that looks more like unipolar depression that the marked highs and lows of bipolar I):
[QUOTE=www.psycheducation.org]
Here’s the list of items which are found with bipolar disorder more often than you would expect by chance alone. This list is adapted from a landmark article by Drs. Ghaemi and Goodwin and Ko. (Drs. Goodwin and Ghaemi are among the most respected authorities on bipolar diagnosis in the world. This important article is online).
1 The patient has had repeated episodes of major depression (four or more; seasonal shifts in mood are also common).
2. The first episode of major depression occurred before age 25 (some experts say before age 20, a few before age 18; most likely, the younger you were at the first episode, the more it is that bipolar disorder, not “unipolar”, was the basis for that episode).
3. A first-degree relative (mother/father, brother/sister, daughter/son) has a diagnosis of bipolar disorder.
4. When not depressed, mood and energy are a bit higher than average, all the time (“hyperthymic personality”).
5. When depressed, symptoms are “atypical”: extremely low energy and activity; excessive sleep (e.g. more than 10 hours a day); mood is highly reactive to the actions and actions of others; and (the weakest such sign) appetite is more likely to be increased than decreased. Some experts think that carbohydrate craving and night eating are variants of this appetite effect.
6. Episodes of major depression are brief, e.g. less than 3 months.
7. The patient has had psychosis (loss of contact with reality) during an episode of depression.
8. The patient has had severe depression after giving birth to a child (“postpartum depression”).
9. The patient has had hypomania or mania while taking an antidepressant (remember, severe irritability, difficulty sleeping, and agitation may – but do not always – qualify for “hypomania”).
10. The patient has had loss of response to an antidepressant (sometimes called “Prozac Poop-out”): it worked well for a while then the depression symptoms came back, usually within a few months.
11. Three or more antidepressants have been tried, and none worked.
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I thought I read on that site that kids who are depressed have a greater chance of developing into bipolar spectrum disorder, but I’m not finding it right now. I’ll look some more.
Anecdotally, I was diagnosed as depressed from age 20 (although I’d clearly been depressed since I was a very young child). At the age of 40, my diagnosis was changed to bipolar spectrum disorder and I was changed from taking SSRIs to taking a mood stabilizer (lamictal). I was mostly oscillating from mildly depressed to really depressed every day, with generally one day a month I was really “high” (relatively). IOW, in a really good mood, loved everyone, very positive and optimistic, loved ALL the music on my iPod…
But 29 out of 30 days I was ranging between degrees of depressed.
Of the list above, 1, 2, 4, 5, 6, 9, 10, and 11 describe me. After years of taking Lexapro, I was finding that it just wasn’t working anymore and went to see a new psychiatrist. What really stuck out for her was the consistent one day per month great mood, the fact that I’ve taken at least 10 different anti-depressants, and that I always responded quickly and strongly to a new anti-depressant (like, within 24 hours when I was put on Celexa). Zoom! I feel grrrrrrrrrreat!
So, I’m a case where it would appear as if my unipolar depression developed into bipolar, but I may have been bipolar all along.