This issue of Psychiatric Clinics, guest edited by Drs. Alan C. Swann and Gabriele Sani, is entitled Mixed Affective States: Beyond Current Boundaries. This issue is one of four each year selected by our series consulting editor, Dr. Harsh Trivedi of Sheppard Pratt Health System. Topics in this issue include: Clinical pictures of mixed states and its relation to temperament and personality; Psychopathology of mixed states; Unipolar agitated depression; Mixed features in mood disorders: the unmet needs of DSM-5; Trauma and mixed states; Suicidal acts and ideations in mixed states; Mixed states in early onset-bipolar disorder; Mixed states during the different phases of the reproductive cycle in women; Mixed states in patients with substance and behavioral addictions; Neurobiology of mixed states; Behavioral sensitization as a mechanism underlying and integrating mixed states; Pharmacological treatments of mixed states; ECT treatment of mixed states; and Innovative treatments including neuromodulation and psychotherapy.