Because mood disorders can involve different types of mental problems, such as major or mild depression and bipolar disorder, there can be some differences in symptoms. Some symptoms of bipolar disorder are alternating periods of hypomania and depression. Major depression can present symptoms that include thoughts of suicide, irritability, anxiety, feeling sad and sleep problems, as noted by Mayo Clinic.
Patients with bipolar disorder, which was referred to as manic depression, can exhibit extreme high or low moods and experience changes in sleep patterns, energy and concentration or thinking. This pattern of alternating episodes of elation and depression can last up to 2 years, as stated by WebMD. When the symptoms of bipolar disorder are mild and do advance to full mania, the condition is referred to as a cyclothymic disorder. In a general population, the probability for the occurrence of bipolar disorder is approximately 2.6 percent, according to Johns Hopkins Medicine.
A mild form of depression that may last 2 or more years is termed a dysthymic disorder, states WebMD. Some symptoms of dysthymic disorder are irritability, fatigue, weight changes, concentration problems and self-esteem issues.
Although there may be some differences in the intensity of the symptoms of bipolar disorder and the two different depressive states, these mood disorders can also present similar symptoms, such as weight changes, dark moods, aggression and the feeling of sadness or hopelessness.