Information obtained with psychiatric questionnaires and rating scales, whilst of great value in the diagnostic process can never render a conclusive diagnosis. A valid psychiatric diagnosis requires thorough examination of a client’s history, personality and current mental status.

ALL questionnaire data must be evaluated for significance by a clinician qualified to do so.

A psychiatric examination may also include laboratory testing to screen for medical conditions that masquerade as psychiatric illness.

Questionnaires and rating scales fall into two broad categories:

1. Those that are applied by a clinician, and

2. Those that are filled in by a client (self-report tools) at the request of a clinician.

The former (clinician-administered questionnaires and rating scales) endeavour to gain a more objective assessment of the patient, whilst the latter (filled in by the client) seek to gain an impression of the client’s subjective experience of symptoms. Clinician-administered instruments often require training.

The Hamilton Rating Scale for Depression is a typical clinician-administered instrument for depression, whilst the Zung Self-Rating Scale for Depression is a typical example of a rating scale falling into the second category. Used together, they provide an invaluable insight into how the client views the severity of their depression relative to clinical opinion.