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Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is Bipolar Disorder?
gpt
bipolar disorder is a mood disorder. it is characterized primarily by drastic mood swings, from extreme euphoric highs (mania), to extreme lows (depression). the phases can last from hours to months at a time. 

there are three main types of bipolar disorder. 

bipolar i is when a person has had at least one severe manic episode (which may include delusional thinking such as believing that they are an actual god, have superpowers, or are invincible) followed by or preceded by a depressive episode (loss of motivation, feelings of guilt and sadness, thoughts of suicide, etc)

bipolar ii is when a person has had at least one depressive episode and one HYPOmanic episode. this is a less severe type of manic episode that may not include the delusional thinking in regular manic episodes. the person may still feel wired,  racing thoughts, and increased energy or anger, but it is less noticeable and less problematic than other manic episodes. 

cyclothmic bipolar disorder is characterized by at least two years of many alternating phases between hypomania and depression. the depressive phases in this disorder may not be as severe as in the two above.

bipolar disorder can seriously disrupt a person’s life, and may require mood stabilizers or hospitalizations if psychosis or suicidal thoughts become too severe.