Finally, when depression is identified by screening, the potential presence of other psychiatric disorders should be noted. Anxiety disorders are frequently diagnosable in depressed patients, although it is unclear whether comorbid anxiety necessitates a change in treatment plans.29 In contrast, a comorbid substance abuse should be recognized and addressed. Similarly, coexisting dysthymia may contribute to depressed patients’ functional impairment.30
Phq-9 reasonable for monitoring treatment
It is important to note that the USPSTF recommendation specifies screening “in clinical practices that have systems in place to assure accurate diagnosis, effective treatment, and followup.” Routine, periodic monitoring is an important aspect of a systems approach to depression care. The PHQ-9, when scored as an assessment scale, and the depression assessment scales listed in Table 2 should be considered for periodic monitoring of patients being treated for depression (SOR=B). Active monitoring may alert the clinician to improvement in symptoms or to a need for treatment adjustment when symptoms do not improve.
The Hamilton Rating Scale for Depression (HAM-D) is often used as a reference standard for monitoring of outcomes in clinical trials, but it is administered by trained interviewers and is therefore impractical to administer in a routine patient care setting. The Beck Depression Inventory (BDI) and Zung Self-rating Depression Scale (SDS) have been used as outcome measures as well, but they are not as sensitive to change over time as the HAM-D.31
The sensitivity to change over time of the PHQ-9 has not yet been formally compared to the HAM-D, but it still represents a reasonable option until the results of such a comparison are available.
