Classically, bipolar disorder is seen as a relapsing-remitting condition with episodes of dizzying and capricious highs (manic episodes) that are clearly separated from melancholic lows and inertia (depressive episodes) and interspersed with remission. Yet, in the clinical setting, the picture is often far more complicated. Bipolar disorder lies on a spectrum with subtypes that are defined by arbitrary and often unfulfilled criteria for the severity and duration of mood episodes, which leads to high rates of “unspecified” diagnoses. “Mixed affective” episodes, in which depressive and manic symptoms co-occur, are the norm rather than the exception. Mood instability also persists out of episode, causing as much impairment as within-episode symptoms¹ and muddying the classically episodic presentation.

典型地，双相情感障碍被认为是一种缓解复发的疾病，头晕目眩，反复无常的高潮发作（躁狂发作）与忧郁症的低血压和惯性发作（抑郁发作）明显分开，并散布着缓解症状。然而，在临床环境中，情况通常要复杂得多。躁郁症的频谱由亚型决定，这些亚型由情绪发作的严重程度和持续时间的任意且通常未满足的标准定义，这导致“未指定”诊断的发生率很高。抑郁和躁狂症状并发的“混合性情感”发作是正常现象，并非例外。情绪不稳定性也持续到发作以外，造成与发作内症状¹一样多的损害，并使经典的情节表现模糊不清。