The diagnosis of bipolar I disorder requires that the individual has at least one manic episode but does not require a history of major depression. Bipolar II disorder is diagnosed if the person has experienced at least one episode of major depression and at least one episode of hypomania (a milder form of mania). "Comorbidity in Bipolar Disorder: The Complexity of Diagnosis and Treatment." Psychiatric Times 26.4 Mar. Mixed features are defined as meeting full diagnostic criteria for a manic episode while also suffering from at least three symptoms of a depressive episode, or meeting full diagnostic criteria for a major depressive episode while also suffering from at least three symptoms of a manic or hypomanic episode. "Schizophrenia and Bipolar Disorder May Share Genetic Origins." Harvard Mental Health Lett 25.12 June 2009: 7. "Our Lost Children: Bipolar Disorder and the Church." Journal of Psychology and Christianity 22.2 (2003): 123-130.
Characteristics of mania must last at least a week (unless it is part of mixed features) and include Symptoms of the manic episode of early onset bipolar disorder in childhood or adolescence tend to include outbursts of anger, rage, and aggression, as well as irritability, as opposed to the expansive, excessively elevated mood seen in adults.
The adolescent with bipolar disorder is more likely to exhibit depression and mixed episodes with rapid changes in mood.
In fact, persistent sadness tends to occur more often than mania in many people with bipolar disorder.
Characteristics of depressive episodes (bipolar depression) include a number of the following symptoms: persistently depressed or irritable mood; feelings of apprehension; frequent crying, inability to feel pleasure; loss of interest in previously pleasurable activities; apathy, low motivation; increased or decreased appetite, weight loss or weight gain, difficulty falling asleep; excess sleepiness, agitation or lack of activity; fatigue/low energy; feelings of worthlessness; lack of concentration; slowness in activity and thought; inappropriate feelings of guilt; hopelessness; thoughts of death, self-harm or suicidal thoughts, plans, or actions.
Bipolar disorder has a number of types, including bipolar I and bipolar II disorder.