The goal of this clinical trial is to learn if cognitive analytic therapy-guided self-help (CAT-GSH) is comparable to cognitive behavioural therapy-guided self-help (CBT-GSH) in terms of whether it is effective and acceptable for people with anxiety or low mood, who are returning to NHS Talking Therapy services for further treatment. The main questions it aims to answer are:

• Does CAT-GSH work well and feel acceptable for people coming back to the Talking Therapies service, compared to CBT-GSH, when taking their characteristics (like age) into account
• Does CAT-GSH work well and feel acceptable for people coming back to the Talking Therapies service, compared to those using CBT-GSH for the first time, when taking their characteristics (like age) into account?

Participants will:

• Choose their preferred treatment
• Complete 6 sessions of either CAT-GSH or CBT-GSH
• Sessions will be weekly or bi-weekly
• Complete routine outcome measures before, during and at the end of therapy

A prospective quantitative, quasi-experimental design will be used to address the primary and secondary questions. PWPs will be trained in delivering CAT-GSH. Participants will choose between CAT-GSH and CBT-GSH and be offered a six-session contact of one-to-one GSH. The Talking Therapies service already collects routine outcome measures, which will be collated and analysed.

Procedure/Intervention The Talking Therapies services routinely perform an initial assessment when someone is referred to their services. Potential participants who meet the inclusion criteria will be identified at the assessment stage.

Tameside and Glossop Talking Therapies service procedure:

The assessor will ask if there is potential interest in a study using a screening script; if the person remains interested, the participant information sheet (PIS) and the consent form will be emailed or posted. At least 48 hours will be left to allow the participant to read the information.

The principal investigator will give a follow-up phone call to answer any potential questions, ask for preference on the therapy, and complete the consent form, which will be emailed or posted back to the Talking Therapies service once completed. The completed consent form will be saved in the site's local file and a copy of the form will be sent to the participant. If the person no longer wants to participate at this stage, the service user will receive the treatment as usual.

Leeds Mental Wellbeing Service procedure:

The assessor will ask if there is potential interest in a study using a screening script; if the person remains interested, the potential participant information sheet (PIS) and the consent form will be emailed or posted. The potential participant will be given 7 days to read the information, email the Leeds service with their preferred treatment, and return the signed consent form to the service if the potential participant does not request further information. 14 days will be given if the participant asks for the material to be posted. If the potential participant requests further information, the clinical lead and principal investigator will contact the potential participant to discuss this. The completed consent form will be saved in the site's local file and a copy will be sent to the participant. If the person no longer wants to participate at this stage or has not emailed within 7 days or returned the forms by post within 14 days, the service user will receive the treatment as usual, so there are no delays.

All services procedure:

The Talking Therapies services collect routine outcome measures, demographics and other data as standard. Sessions can take place face-to-face, online, or by telephone. The sessions last 35 minutes, for a total of six sessions. Sessions are carried out weekly or bi-weekly.

The psychological wellbeing practitioner (PWP) will record the third session with the participant, so the research team can perform a randomly selected competency check on the CBT-GSH and CAT-GSH delivered to service users. The recording will be sent to the research team, with no personally identifiable information on the file name. However, due to the nature of recordings, they may contain identifiable information. Participants will be made aware of this in the PIS.

The analysis stage will aim to start in December 2025, to explore the outcome measure data.

Inclusion Criteria:

• Previously received CBT-GSH at same participating NHS Talking Therapies service
• Presenting with anxiety or depression
• Deemed suitable for step 2 low-intensity therapy, through assessment by a qualified PWP

Exclusion Criteria:

• Previously received high-intensity therapy since receiving CBT-GSH
• The previous treatment episode was in another NHS Talking Therapies service.
• Not fluent in English

Individuals who are not fluent in English will be excluded from the study due to not having translated CAT-GSH workbooks available and limited funding to translate any workbooks.

Only anonymized data will be shared. Personal data will not be.

At the end of the study (approximately May 2026), data will be stored on the University of Sheffield's ORDA (online research hub) for 10 years according to the University of Sheffield's retention period.

Information can be requested through ORDA by those who qualify for membership.