2 Evidence gaps

This section describes the evidence gaps, why they need to be addressed and their relative importance for future committee decision making.

The committee will not be able to make a positive recommendation without the essential evidence gaps (see section 2.1) being addressed. The companies can strengthen their evidence base by also addressing as many other evidence gaps (see section 2.2) as possible. This will help the committee to make a recommendation by ensuring it has a better understanding of the patient or healthcare system benefits of the technologies.

2.1 Essential evidence for future committee decision making

Effectiveness compared with NHS standard care

The technologies should be compared with non-digital standard care. These are the treatments offered for a new episode of less severe or more severe depression in NHS Talking Therapies for anxiety and depression services, in line with NICE's guideline on depression in adults.

Use of outcome measures routinely collected in the NHS

More evidence of the effectiveness of the technologies is needed because some studies used outcome measures that are not routinely collected in the NHS. Rates of recovery, reliable recovery, reliable improvement and reliable deterioration are the recovery standards measured in NHS Talking Therapies for anxiety and depression services (see NHS England's NHS Talking Therapies manual). Although not routinely collected in the NHS, more information on the effect of the technologies on relapse is also needed to help evaluate their clinical and cost effectiveness.

Adverse response to treatment

Few studies reported adverse effects or when additional treatment or stepping up of care was needed. Stepping up of care means that people have more intensive treatments if they do not benefit from initial treatments. This information would help the committee decide whether these technologies can be used safely in the NHS.

Resource use

More information on resource use during and after treatment is needed to help the committee understand the technologies' cost effectiveness. For example, the technologies could reduce practitioner or therapist time compared with other psychological interventions. This could free up resources that could be used to increase access to treatment or reduce waiting times.

2.2 Evidence that further supports committee decision making

Patient experience and rates and reasons for stopping treatment

This information will help the committee understand how people with depression interact with the technologies and if they find them acceptable to use. Also, it will highlight any challenges in using the technologies, such as problems with access, or their effect on waiting times.

Health-related quality of life

More evidence is needed to understand the cost effectiveness of the technologies, and health-related quality of life is an important driver of health economic evaluation. The EQ‑5D is the preferred tool for measuring health-related quality of life but non-standard measures such as the Recovering Quality of Life questionnaire may better capture benefits in people using mental health services within the NHS.