ISRCTN16806208.

Study name	A randomised controlled trial of therapist‐assisted online psychological therapies for post‐traumatic stress disorder.
Methods	Randomised controlled trial
Participants	Aged ≥ 18 with PTSD resulting from traumatic events experienced in adulthood.
Interventions	Experimental arm Internet‐delivered psychological therapy started immediately Comparator arm Internet‐delivered psychological therapy started after a delay of 13 weeks Both therapies involve completing therapy modules online and assignments over 3 months, with guidance via messages and weekly telephone calls with an experienced psychological therapist.
Outcomes	Time points for assessment: baseline; 6 weeks; end of therapy/waiting; and 3 months, 6 months, and 12 months after end of therapy Primary outcome: PTSD symptoms (measured by weekly questionnaires and by interviewing participants regarding their experiences)
Starting date	January 2017
Contact information	Maxie Scheske maxie.scheske@psy.ox.ac.uk
Notes	www.psy.ox.ac.uk/research/oxford-centre-for-anxiety-disorders-and-trauma/anxiety-disorders/post-traumatic-stress-disorder