Evidence on which the specific mental disorder guidelines are based

The diagnosis sections are based on the ICD-10 classification of mental disorders. ICD-10 is itself a consensus document, tested for reliability. The ICD-10 diagnostic criteria presented here have been tested among primary-care professionals to check for face validity and usefulness. References supporting evidence have been given in line with the principles set out below.

Treatments (medication and psychotherapies)
The recommendations about medication are all in line with the British National Formulary (BNF). Where recommendations about medication are unexceptional and in line with both the BNF and established practice for many years, references have not been given. References have been reserved for key statements about medication and about particular psychotherapies or for statements about which evidence and opinion are divided. Where possible, evidence has been given from Cochrane reviews, high quality published reviews and meta-analyses or randomised controlled trials (RCTs). Discussions have been held with experts and authors of key areas of research. The evidence has been graded as follows:

Strength of the evidence supporting the recommendation
A = Good evidence to support
B = Fair evidence to support
C = Preliminary evidence to support

Quality of the evidence supporting the statement
I = Evidence obtained from a meta-analysis of trials, including one or more well-designed RCTs
II = Evidence obtained from one well-designed RCT
III = Evidence obtained from one or more controlled trials, without randomisation
IV = Evidence obtained from one or more uncontrolled studies
V = Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees. Occasionally the 'respected authorities' comprise collective patient experience. Where this is the case, it is clearly stated.

Where a qualitative review of previously published literature without a quantitative synthesis of the data is referenced, it has been graded in accordance with the type of studies the review includes. Where a reference is marked 'N', this means that the note contains additional information or a discussion of the issues, as well as the reference.