The iChill Project: can generalised anxiety disorder be prevented and treated using e-health interventions?

GAD-7, a 7 item self-report scale measuring symptoms of GAD. In addition, for the Treatment trial any reductions in GAD diagnoses will be assessed using the Anxiety Disorders Interview Schedule-IV (ADIS-IV) (a clinician administered interview) which will be administered at assessment, post-intervention and 12 months post-intervention.

1. Fewer cases of GAD at six months post-intervention, as measured by a second administration of the MINI
2. Reduction in worry, measured by the Penn State Worry Questionnaire
3. Anxiety sensitivity, as measured by ASI
4. Reduction in depression symptoms assessed by the CES-D and PHQ-Depression
5. Alcohol use measured by AUDIT, disability, measured by the 'Days Out of Role' questions from the US National Comorbidity Survey and number of hours worked per day
6. Improvements in health knowledge using formats previously developed for depression and adapted for anxiety (Anxiety Literacy [A-Lit])
7. Help-seeking using scales measuring actions taken to overcome anxiety adapted from parallel depression versions of these, perceived need for treatment assessed by the following item: "Was there ever a time in the last 12 months when you felt that you might need to see a health professional because of problems with your emotions or nerves?"
8. Adherence measured by survey return rates and website usage
9. Preferences for treatment type and expectations of the trial will be assessed using previously developed formats, and levels of psychological distress using the K10

Further outcome measures to be included in the assessments may also be potential risk factors and mediators of the effectiveness of the intervention. Personal and perceived stigma toward those with GAD will be assessed by a new scale currently under development - the Generalised Anxiety Stigma Scale, while participants' ability to identify mental illness will use measures using prototypes, and perceptions of personal health will be rated using a self-perceived emotional health item, symptoms of social phobia will be assessed using the Social Phobia Inventory and a new social phobia screener that is in development, whilst symptoms of panic will be measured using PHQ Panic and a new panic disorder screener that is in development. Availability of social support will be assessed using MOS Social Support, preferences for treatment type and expectations of the trial will be assessed using previously developed formats. Predictors including smoking, medication use, perceived helpfulness of sources, childhood adversity, physical health and life events will use scales developed for a previous study.

In addition, for the Treatment trial worry will be measured by the Anxious Thoughts Inventory, somatic symptoms associated with worry will be measured by the Worry and Anxiety Questionnaire - Somatic Subscale, the impact of worry on participants' lives will be measured by the Life Interference Scale, and global social, occupational and psychological functioning will be assessed by the Global Assessment of Functioning scale. These scales will be administered at baseline, post-intervention, 6 months post-intervention, and 12 months post-intervention.