Younger readers may not appreciate that prior to DSM-IV, the phenomena that we today call “mood disorders” were identified more precisely as affective disorders, denoting a fundamental distinction between disturbances of mood (the subjective experience of emotion) and affect (the objective behavioral expression of mood). Given that problems with “mood” are ubiquitous throughout virtually all aspects of psychopathology, links between the signs and symptoms of “mood problems” are critical both to nosological classification and to identifying targets of pharmacotherapy interventions. Features associated with affective disorders encompass problems with energy, the sleep–wake cycle, thinking and perception, impulse control, cognition (e.g., attentional processing, problem-solving), motivation/arousal, and eating behaviors, among others.

In this chapter, we present information about the treatment of mood/affective disorders as a broad overarching category, with subdistinctions (such as polarity) highlighted as clinical descriptors, rather than as fundamentally different illnesses. This may trouble some readers. Yet, one could slice the affective pie innumerable ways.