Key points are not available for this paper at this time.
Flashbacks are returns of imagery for extended periods after the immediate effect of hallucinogens has worn off. The most symptomatic form is recurrent intrusions of the same frightening image into awareness, without volitional control. The author compares flashbacks with other clinical phenomena; he believes that psychotherapy is helpful, especially if there is a focus on the traumatic and screening aspects of the imagery.
Mardi J. Horowitz (Wed,) studied this question.