1. What’s the different between bipolar 1 and bipolar 2?
In both conditions, a patient may experience episodes of Major Depression. Also in both cases, they have mood states which would be on the other end of the pole, so if depression would be considered "down," they have periods that are considered "up" relative to normal mood. The difference is in the severity or intensity of the up phases. In Bipolar 1, the ups are more intense and extreme and may even include hallucinations or loss of touch with reality. Psychiatrists would diagnose this as mania. These episodes can be quite dramatic and patients can get into a lot of trouble during these phases either through shopping sprees, or extremely impulsive and reckless behaviors which can often lead to interactions with law enforcement. In Bipolar 2, the ups are relatively milder and are labeled as hypomania. Patients may actually feel abnormally good and not view these episodes as a problem in themselves.
2. Are they treated differently? And if so, why?
In both Bipolar disorders, the evidence suggests that in general the core foundation of treatment should be a category of medications known as "mood stabilizers." Psychiatrists are trained to screen for a history of manic or hypomanic symptoms even if a patient is coming in complaining mainly of depression. The reason for this is that using standard Major Depression treatments such as antidepressants in patients who actually have Bipolar Disorder can cause the condition to worsen. A patient with Bipolar 1 is less likely to receive an antidepressant without a mood stabilizer if screened properly, because full manic episodes are usually pretty clear-cut. The challenge is that in Bipolar 2, even when a trained clinician is screening, the patients may not actually realize that those hypomanic episodes were abnormal because to them they just felt great at the time and thought that is what it’s like to be feeling good.
3. Can people have both types of bipolar disorder or progress from one to the other?
The way our current diagnostic system works, once a person has had a clearly documented manic episode, their diagnosis will be Bipolar 1 and never convert to Bipolar 2. The rationale is that once a patient has had a full manic episode, there will always be the risk of another full manic episode. If a person has Bipolar 2 and has had episodes of hypomania, there is the possibility that at some point in the future they may have a full manic episode, at which point their diagnosis would change to Bipolar 1. What I often see clinically is that patients may be diagnosed with Bipolar 2 in their late teens or early twenties, which may have been accurate at the time because they only had hypomanic episodes up until that point. However, at some point in their mid or late-twenties, they may experience a full manic episode and have their diagnosis changed to Bipolar type 1. I think in a lot of these cases only time could tell what the long-term diagnosis would be because they were still relatively young with a developing brain when they were initially diagnosed with Bipolar 2. As the years went on, their brain continued to grow and develop into a more final form.