Healing through emotional arousal is an ancient idea. Abreaction may yield lasting, brief, or no improvement, or alternatively sensitization. The predictors of outcome are unclear. The emotional experience of relevant exposure therapy yields more reliable improvement; forgotten traumas may surface, which ease as exposure proceeds. High arousal does not enhance the gains, but emotional engagement in exposure seems crucial for habituation to occur. Habituation is specific to the fear cues presented, marked generalization being unusual. Emotional experience irrelevant to a phobia can also improve the phobia, but the duration of such relief is unclear and different mechanisms may be involved. Fear-reduction is unreliable with non-exposure methods. Though counterproductive during exposure, dissociation and denial may have some uses. Optimal gains may come from being able to modulate activation or suppression to suit particular circumstances.
