title: Internet cognitive behavioural therapy for mixed anxiety and depression: a randomized controlled trial and evidence of effectiveness in primary care.
abstract: BACKGROUND
  Major depressive disorder (MDD) and generalized anxiety disorder (GAD) have the highest co-morbidity rates within the internalizing disorders cluster, yet no Internet-based cognitive behavioural therapy (iCBT) programme exists for their combined treatment.
  
  
  METHODS
  We designed a six-lesson therapist-assisted iCBT programme for mixed anxiety and depression. Study 1 was a randomized controlled trial (RCT) comparing the iCBT programme (n = 46) versus wait-list control (WLC; n = 53) for patients diagnosed by structured clinical interview with MDD, GAD or co-morbid GAD/MDD. Primary outcome measures were the Patient Health Questionnaire nine-item scale (depression), Generalized Anxiety Disorder seven-item scale (generalized anxiety), Kessler 10-item Psychological Distress scale (distress) and 12-item World Health Organization Disability Assessment Schedule II (disability). The iCBT group was followed up at 3 months post-treatment. In study 2, we investigated the adherence to, and efficacy of the same programme in a primary care setting, where patients (n = 136) completed the programme under the supervision of primary care clinicians.
  
  
  RESULTS
  The RCT showed that the iCBT programme was more effective than WLC, with large within- and between-groups effect sizes found (>0.8). Adherence was also high (89%), and gains were maintained at 3-month follow-up. In study 2 in primary care, adherence to the iCBT programme was low (41%), yet effect sizes were large (>0.8). Of the non-completers, 30% experienced benefit.
  
  
  CONCLUSIONS
  Together, the results show that iCBT is effective and adherence is high in research settings, but there is a problem of adherence when translated into the 'real world'. Future efforts need to be placed on developing improved adherence to iCBT in primary care settings.
authors: Clinical Research Unit for Anxiety and Depression, School of Psychiatry, University of New South Wales at St Vincent's Hospital, Darlinghurst, NSW, Australia.
authors: J M
authors: JM
authors: Newby
authors: A
authors: A
authors: Mackenzie
authors: A D
authors: AD
authors: Williams
authors: K
authors: K
authors: McIntyre
authors: S
authors: S
authors: Watts
authors: N
authors: N
authors: Wong
authors: G
authors: G
authors: Andrews
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D015928:Cognitive Behavioral Therapy / Q000295:instrumentation / Q000379:methods*; D015897:Comorbidity; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020407:Internet / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011320:Primary Health Care / Q000592:standards; D016896:Treatment Outcome; D014850:Waiting Lists; D055815:Young Adult