Interpersonal and social rhythm therapy is an individual psychotherapy designed specifically for the treatment for bipolar disorder. Interpersonal and social rhythm therapy grew from a chronobiological model of bipolar disorder postulating that individuals with bipolar disorder have a genetic predisposition to circadian rhythm and sleep-wake cycle abnormalities that may be responsible, in part, for the symptomatic manifestations of the illness. In our model, life events (both negative and positive) may cause disruptions in patients' social rhythms that, in turn, perturb circadian rhythms and sleep-wake cycles and lead to the development of bipolar symptoms. Administered in concert with medications, interpersonal and social rhythm therapy combines the basic principles of interpersonal psychotherapy with behavioral techniques to help patients regularize their daily routines, diminish interpersonal problems, and adhere to medication regimens. It modulates both biological and psychosocial factors to mitigate patients' circadian and sleep-wake cycle vulnerabilities, improve overall functioning, and better manage the potential chaos of bipolar disorder symptomatology.