bipolar without depression

Can there be mania without bipolar disorder?
As far as I know, mania is a phase of bipolar, depression being the other.
However I know someone who told me they have “mania” and sees a therapist. However this person only gets mild mania, and has never shown any signed of depression. When I asked him if he was bipolar, he said “no”.
Can someone get mania without depression/bipolar disorder?
No, according to the DSM-IV-TR, an episode of mania or hypomania alone even without depression constitutes a diagnosis of bipolar disorder.
It is possible that your friend has type II bipolar disorder, which is characterized by predominantly depressive symptoms and “hypomania”, which is mania that is not as severe as a full manic episode.
Also, just because someone does not show any signs of “depression” does not mean that they do not meet the criteria for major depressive disorder. A depressed mood is not necessary to make the diagnosis- the other necessary feature can be anhedonia, or a lack of interest or pleasure from activities/life.