242 ASSESSMENT AND INTERVENTION STRATEGIES
There have been reports of success in using very intensive, massed exposure in
which individuals begin with the most difficult items in the hierarchy. In fact this
ungraded, intensive exposure has been found to be highly successful in treating panic
disorder with agoraphobic avoidance (see discussion by Craske & Barlow, 2001; White
& Barlow, 2002). However, graduated exposure is usually more acceptable to individu-
als with anxiety disorders who already are concerned about elevated anxiety as a result
of exposure. The prospect of confronting their “worst fears” from the outset is too
risky for most individuals who then might be inclined to refuse further exposure-based
treatment (Antony & Swinson, 2000a). No doubt graduated exposure is the preferred
modus operandi, although the therapist must guard against progressing too slowly up
the exposure hierarchy.
Frequency and Duration
Behavioral manuals on situational exposure recommend daily sessions on a 5-day per
week basis over 3–4 week time intervals with each exposure lasting up to 90 min-
utes (e.g., Kozak & Foa, 1997; Steketee, 1993, 1999). At its most intense, exposure
procedures have been prescribed 3–4 hours a day, 5 days a week (Craske & Barlow,
2001). Although this latter procedure represents an extreme upper limit, it is prob-
ably true that the exposure-based treatments offered in specialized behavioral centers
probably involve more exposure work than what is often seen in more generic natural-
istic clinical settings. Failure to achieve within- session and between- session decrements
in fear response with exposure therapy is a significant predictor of poor treatment
response (e.g., Foa, 1979; Foa, Steketee, Grayson, & Doppelt, 1983; Rachman, 1983).
Although a number of factors may be responsible for poor treatment outcome, it is
possible that individuals may have received an insufficient number of exposure sessions
especially when considering the treatment regimens often provided in mental health
centers.
There is some evidence that a concentrated presentation of exposure is more effec-
tive than spacing exposure sessions so they occur more sporadically (Antony & Swin-
son, 2000a; Foa & Kozak, 1985), although there is considerable inconsistency in the
research on this question (see Craske & Barlow, 2001). Antony and Swinson (2000a)
recommend three to six longer practice sessions per week interspersed with brief prac-
tices throughout the day. No doubt the most prudent clinical advice would be to encour-
age at least daily exposure practice when this is a primary intervention strategy in the
treatment plan. Every effort should be made to avoid the negative effects of insufficient
exposure practice on treatment response.
It would appear that prolonged exposure sessions are better than short presenta-
tions (Foa & Kozak, 1985), with decreases in anxiety evident after 30 to 60 minutes of
exposure. Foa and Kozak (1986) argue that longer exposure intervals may be necessary
for more pervasive, intense, and complex fears such as agoraphobia. Individual differ-
ences in response to exposure can be expected, so the clinician relies on reductions in
subjective anxiety to indicate when to end an exposure session. Antony and Swinson
(2000a) suggest a decrease in anxiety to a mild or moderate level (30 to 50/100) as
indicated by self- report and observer ratings as the criteria for successful completion
of an exposure session. Taylor (2006) considers a 50% reduction in anxiety indicative
of successful exposure. Although differing in their specific findings, the behavioral lit-