Before you sign up for this study, use the checklist below to make sure you are eligible to take part.

• You are over 18 years of age and located in the UK.

• You have access to a smartphone* with a reliable internet connection.

• You have symptoms of generalised anxiety and worry and are seeking help. You may be experiencing symptoms of low mood, but if you are particularly struggling with low mood this study may not be for you. You are not currently receiving therapy.

• You are not experiencing symptoms of psychosis, personality disorder, eating disorder, Post-Traumatic Stress Disorder, Bipolar Disorder, substance abuse.

• You do not have a formal diagnosis of an untreated mental health condition (except for generalised anxiety or depression).

• You have not had a change in medication prescribed for a mental health condition (e.g. antidepressants) in the past 3 months.

• You do not have an impairment that would prevent you from being able to use a smartphone (this app has not yet undergone accessibility evaluation)

• You are literate in the English language (this app is only currently available in English)

• You have not previously participated in a study with ieso using the smartphone app

*The app will only work with the following smartphones: Apple iOS15 or Android 9 (API level 28)