Skip to content
View commentaries on this research

Please note that this summary was posted more than 5 years ago. More recent research findings may have been published.

This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

This Cochrane review found limited evidence that specialist support for primary care through a consultation liaison model may improve care for people with mental health illness for up to 12 months. Primary care is framed as general practice in the UK or family physicians in North America. Consultation liaison is where a mental health specialist supports the first contact physician in their diagnosis and management, while care remains with the primary care provider. The specialist may or may not have direct contact with the patient. Half of the trials were from the USA, where specialist care is normal for illness of all severity, and only one from the UK. Relevance to the NHS is likely to be limited.

Most studies were in people with depression with limited evidence available for other mental health conditions. Evidence was strongest for an effect on adherence to treatment, with few studies examining effects on patient mental health outcomes. The review did not examine whether such support is cost-effective, though it did appear to be costly. While specialist support for people with common mental health problems may improve outcomes, this review does not provide reliable evidence that consultation liaison is the most effective model of support.

Why was this study needed?

Common mental health problems, such as depression and anxiety, are estimated to affect up to 15% of the UK population at any one time. In 2013-14 over 1.7 million adults accessed NHS services for severe or enduring mental health problems. Mental health conditions costs over £105 billion a year in England alone, including £21.3 billion in health and social care costs, £30.3 billion in lost economic output and £53.6 billion in human suffering. Despite this, many people are not diagnosed or do not receive adequate treatment.

Consultation liaison is where a mental health specialist works with the GP to support diagnosis and the delivery of care. The specialist is often a psychiatrist, but can also be a mental health nurse, psychologist or social worker. While there is a history of consultation liaison within the hospital setting, this review is the first meta-analysis of consultation liaison services in primary care settings for people with mental disorders.

What did this study do?

This was a systematic review and meta-analysis of 12 randomised controlled trials comparing consultation liaison in primary care with standard care (11 trials) or collaborative care (one trial). Eight of the trials were in people with depression, others included various problems such as anxiety or unexplained symptoms. Half of the trials were conducted in the United States, with one in each of Australia, Canada, Germany, Italy, the Netherlands and the United Kingdom.

To count as consultation liaison there had to be at least one session where the specialist consulted with the GP. This could include education, problem solving, or feedback on diagnosis and prescribing. There did not have to be direct contact between the specialist and the patient; if there was, this could be done separately or jointly with the GP. The liaising specialist was a psychiatrist in most trials. See Definitions tab for more details of the interventions. Collaborative care differs from consultation liaison in that there is a third health professional involved, such as a case manager.

This was a good quality Cochrane review. However, the quality of included trials was low and most had a high risk of bias, because of incomplete outcome data, for example. For most outcomes only two to four trials could be included in the meta-analysis. Results are therefore preliminary in nature and need to be treated with caution.

What did it find?

  • Consultation liaison may improve adherence to treatment between three and 12 months following the start of treatment (risk difference [RD] 0.16, 95% confidence interval [CI] 0.08 to 0.24). A variety of measures were used to assess adherence. This came from a meta-analysis of seven trials and the quality of evidence was considered moderate.
  • Consultation liaison may increase the number of GPs providing adequate treatment between three to 12 months (from a meta-analysis of three trials) and prescribing suitable medication up to 12 months after the start of treatment (from a meta-analysis of four trials). However, the evidence was considered of low quality for both outcomes.
  • Patient mental health was the main outcome this review set out to examine, but there was low quality evidence on this, provided by just two to three trials. Defined by a reduction in the score on symptom scoring checklists from baseline. Two trials suggested that consultation liaison may have a short term effect on improvement in mental health at up to three months (RD 0.13, 95% CI 0.04 to 0.22). A single trial also found that it improved patient satisfaction.
  • The single trial comparing consultation liaison with collaborative care found that collaborative care was superior for symptoms, disability and general health at up to 12 months and prescription of adequate treatment.

What does current guidance say on this issue?

There is no current guidance on the use of consultation liaison in primary care.

What are the implications?

This review suggests that consultation liaison may provide some benefits compared to standard care for people with mental health illness in primary care, but the evidence is weak. Most evidence relates to people with depression, with no evidence for its use in conditions such as schizophrenia or bipolar disorder. There was also no data on whether consultation may benefit specific groups of people, for example depending on age, or whether this is a first or recurrent episode of illness.

The one trial in this review that compared consultation liaison with collaborative care showed superiority of collaborative care. However, there are no formally recognised definitions of collaborative versus consultation liaison care. Therefore, a 2012 Cochrane review on collaborative care for depression and anxiety problems included five of the 12 trials included in this review. The 2012 review found that collaborative care improved symptoms, medication usage and satisfaction.

This review contributes to evidence that specialist support for GPs providing care for people with mental health illness can improve outcomes. However, whether the support should be provided through consultant liaison or another delivery model remains unclear.

Any change to delivery of mental health services or models that includes specialist care, will also need to consider costs of the service. One US study in this review reported that the additional ‘average’ cost was USD 6,789 for consultation liaison and USD 7,946 for collaborative care.



Gillies D, Buykx P, Parker AG, Hetrick SE. Consultation liaison in primary care for people with mental disorders. Cochrane Database Syst Rev. 2015;9:CD007193.



Archer J, Bower P, Gilbody S, et al. Collaborative care for depression and anxiety problems. Cochrane Database Syst Rev. 2012;10:CD006525.

Centre for Mental Health. Economic and social costs of mental health problems. London: Centre for Mental Health; 2010.

Hedrick SC, Chaney EF, Felker B, et al. Effectiveness of collaborative care depression treatment in Veterans' Affairs primary care. J Gen Intern Med 2003;18(1):9-16.

HSCIC. Mental Health. Leeds: Health & Social Care Information Centre; 2015.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre


  • Share via:
  • Print article


The role of the consultation liaison specialist varied across trials.

Example consultation liaison interactions with patients included: assessment interviews; referral to specialist mental health care; provision of educational material such as booklets and DVDs; an education session; counselling, structured advice or treatment monitoring. Most interactions were face-to-face, though some were by telephone.

Example consultant liaison interactions with providers included: meetings to discuss the patient’s diagnosis, treatment planning or progress, or both, either face-to-face or by telephone; provision of written reports from the mental health specialist to the primary care provider concerning assessment, treatment recommendations or progress, or both; availability of ongoing consultation advice and support as needed; facilitated referral; provision of face-to-face professional development training; educational material, such as treatment guidelines.


Back to top