In our most recent paper, published in the Journal of Obsessive-Compulsive and Related Disorders, we investigate sudden gains in internet-based CBT for OCD. A sudden gain means a large improvement in symptoms between two therapy sessions (i.e. weeks in internet-based CBT), that is stable once the improvement has taken place. We used data from a previous trial where 128 participants received internet-based CBT.
We found that 38% of the patients experienced a sudden gain. Sudden gainers showed significantly larger improvements on the clinician-administered Y-BOCS than non-sudden gainers at post-treatment (d = 1.11), as well as at 3-month (d = 1.06), 12-month (d = 0.88) and 24-month follow-up (d = 0.77). Sudden gainers also showed significantly less severe OCD symptoms than gradual gainers at post-treatment (d = 0.50), as well as 3-month (d = 0.55) and 12-month follow-up (d = 0.57). In addition, patients receiving DCS showed a significantly higher rate of sudden gains.
We conclude that sudden gains are common in ICBT for OCD and are associated with favourable short and long-term treatment outcomes. Sudden gains is something we will be investigating further in our other clinical trials for OCD and related disorders.