Depressive symptoms
Patient Health Questionnaire – 9 items (PHQ-9)
The PHQ-9 is the instrument that the committee of experts recommends to evaluate, from a survey, the symptoms of depression (Information sheet 3). It facilitates the collection of information on the presence and intensity (severity) of depressive symptoms during the past two weeks. A review of the literature allowed for an assessment of the acceptable psychometric properties when the standard threshold of 10 is used (English version of the instrument) (Pettersson et al., 2015). It is the only instrument that the authors of this review of the literature recommend for screening cases. The MINI is recommended to make a diagnosis of depression (Pettersson et al., 2015).
There is also a two-item version (PHQ-2) that only allows screening for depression without any indication of the severity of the symptoms. It produces good results but it makes it possible instead to pinpoint with greater certainty those who are not suffering from depression (up to 97% sensitivity, up to 67% specificity, PPV1 of 38% and NPV2 of 93%) (Maurer, 2012). Consequently, it is preferable to continue the questionnaire with the nine-item version when the respondent replies positively to the first two questions.
A version for adolescents, the PHQ-A, is also available. It is similar to the PHQ-9 and uses vocabulary adapted to the target clientele (11 to 17 years of age). The PHQ-A has not been translated into French. However, the PHQ-9 is often used among adolescents and studies have shown good metrological qualities when such is the case (Maurer, 2012; Richardson et al., 2010). The PHQ-9 is frequently used jointly with the GAD-7, which assesses anxiety. The PHQ-9 is now the instrument that has been used to assess depression in the Canadian Community Health Survey (CCHS) since the 2015-2016 cycle (Table 4), which provides statistics for Québec.
Center for Epidemiologic Studies – Depression Scale (CES-D)
The 20-item CES-D is another tool frequently used in surveys (Information sheet 4, Questionnaire 3). There are several versions of the CESD, including the revised version in 2004 (CESD-R), which is still rarely used, and a short version (CES-D10), which includes 10 of the 20 items from the first version. The most recent scientific articles are starting to call into question the use of this instrument, among other things because of criticism of the optimum structure of factors, the content of the items (Carleton et al., 2013) and the instrument’s sensitivity and specificity (Pettersson et al., 2015). The standard threshold of 16 is acknowledged to have a high proportion of false positives (Smarr and Keefer, 2011). Consequently, researchers have attempted to adapt the threshold and there are now several interpretation thresholds that differ depending on the language of administration, the study or patient population and sex. The PHQ-9 is being increasingly recommended compared with the CES-D because of its ability to measure the severity of the depressive episode, its smaller number of items, and the simpler interpretation of scores (Obbarius et al., 2017).
Mini-International Neuropsychiatric Interview (MINI)
The MINI, as described above, is an instrument that could be used for smaller surveys since a trained interviewer must use it during a structured interview, which is usually more costly than a self-report questionnaire (Information sheet 5) (Sheehan et al., 1998). The MINI evaluates 17 mental health problems, including major depressive episodes. It allows for a diagnosis to be made when it is used in accordance with the administration criteria. It measures the absence or presence of disease, often based on stringent criteria that satisfy those in the Diagnostic and Statistical Manual of Mental Disorders (DSM). It therefore differs from screening tools, whose continuous scale assesses different levels of symptoms.
The module that allows the diagnosis of a major depressive episode can be used alone (independently of the other modules in the MINI) and contains nine items. A review of the literature allowed for an average estimated sensitivity of 95% and an average specificity of 84% (English version of the instrument) (Pettersson et al., 2015). It is one of two “interview” type instruments that the authors of the review of the literature recommend to diagnose depression (Pettersson et al., 2015). Since the instrument is protected, a user licence must be obtained.
The licence is often free of charge for the English version while a fee may apply to the translated versions depending on the user profile. Accordingly, since the instrument is protected and is updated with each new version of the DSM (the most recent version of the MINI is 7), the questionnaires are not included in this toolkit (Sheehan and Lecrubier, 2018).