Common Mental Disorders Depression - New Zealand Doctor

Overall mental health
A number of tools have been validated for assessment of common mental disorders,
but the PHQ-9 appears to be the most robust: it is well-validated, acceptable to
patients and quick for practitioners to review. 307 Other acceptable tools are the
General Health Questionnaire (GHQ-12) 312,313 and the Common Mental Disorder
Questionnaire (CMDQ). 314 A New Zealand tool, CHAT, appears to have good
sensitivity and specificity for a range of lifestyle and mental health risk factors
(depression, anxiety, alcohol and other drug misuse, problem gambling, stress, abuse,
anger problems, and tobacco use). 305 It is less accurate as a check for inactivity
and eating disorders. It should be noted that validation of the CHAT tool utilised a
composite gold standard comprising other validated screening tools and diagnostic
tests, rather than diagnostic interviews for all conditions. 305 The CHAT tool has been
found acceptable in a large multi-ethnic New Zealand population. 301,315
Depression and anxiety
The verbal 2–3 question screening tool for depression (see Box 5.2) is as accurate
as longer tools and is acceptable and feasible for use in New Zealand populations. 299
The Help question (see Box 5.2) has been validated in a written form. 302
The PHQ-9 is reliable and valid for identifying depression and also for severity
assessment, 316-320 and it is sensitive to changes for both major depression and
dysthymia. 321 Other brief tools, such as the Center for Epidemiological Studies
Depression scale (CES-D), 322 the World Health Organization Wellbeing Index
(WHO-5), 319 and Duke-Anxiety-Depression scale (Duke-AD) 323 are less accurate
for routine use in primary care.
Both the GAD-7 and the 2-question version of the same instrument (GAD-2)
are valid for detecting anxiety disorders. 298,324
The K10 questionnaire measures psychological distress, focusing on anxiety
and depression, and has been widely used in population surveys and secondary
care clinical settings. 34,308 It has not been validated for test-retest reliability or for
sensitivity to change 325 and no evidence was found on its validity in primary care.
The recommended cut-off points are based on data from community samples. 325
No valid case-finding tools for dysthymia were identified.
Alcohol and/or substance abuse
The AUDIT questionnaire was found to be the most accurate tool for identifying
risky, harmful and hazardous drinking, 310 while CAGE (a 4-question acronym) is the
most accurate for identifying lifetime alcohol abuse or dependence. 311 A US study 300
identified two questions adapted from CAGE which detected 80% of current drug
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Identification of Common Mental Disorders and Management of Depression in Primary Care