The authors examined how heroin addicts' affect varies in relation to perceived levels of challenges and skills in daily activities. Fourteen male residents of a therapeutic community completed 21 end-of-day diaries measuring affect. Unexpectedly, addicts had comparable positive
affect to, and less negative affect, than a nonclinical student sample. Positive affect correlated with the imbalance of challenges and skills. Heroin addicts deviate from the flow model of healthy functioning as they optimize affect in states of either overcontrol or lack of control.