NHS England has continued to use a metric of recovery for those undergoing its’ Talking Therapy service that is known to be invalid. This costs the British taxpayer about £2 billion a year. It boasts a 50% recovery rate. The primary metric used is the PHQ-9, an alleged measure of the severity of depression, with a cut-off of 10 or more used to designate a case of depression.
Recently Hlynsson et al published a paper titled ‘Why are we still using the PHQ-9?‘ they observed fundamental problems:
- a confusion about whether the instrument is measuring the frequency of a symptom or how bothersome it is
- because of this confusion clients can respond differently on separate occasions and this does not necessarily reflect a change in symptomatology
- false positive rates often exceed 50%
- The PHQ-9 uses a two-week time frame but it is administered at every session in NHS Talking Therapies, which are often weekly. The instrument has not been validated for use in this way
- ‘there is a need for greater transparency and independent evaluation of assessment t. ools’
The PHQ-9 is at best a measure of the severity of depression, it is nonsense to use it as a yardstick for every disorder that presents to NHS Talking Therapies. This echoes the findings of Panayotiou et al 2026 ‘this study identified widespread misinterpretation of the PHQ instructions across community and clinical samples, raising doubts about its validity for both research and clinical decision-making’.
The PHQ-9 had its’ origins in Pfizer’s marketing of a drug, 20 years on it’s the mainstay of NHS England’s marketing.
A client could make a claim that NHS Talking Therapies has not discharged their duty of care to them by relying on a dubious diagnostic instrument and navigating treatment accordingly. Their plea in mitigation that the Service doesn’t make diagnoses, rings hollow.
Dr Mike Scott