5 Features of inadequate treatment for Depression are:
- The most common source of lack of response in depression is the administration of inadequate dosage. With some antidepressants, the tricyclic antidepressants (TCAs), there is evidence for a relationship between plasma levels and therapeutic outcome
- Treatment duration with antidepressants. There is some evidence that elderly patients may require longer exposure to medication. At least adequate dosage during 4 weeks is the absolute minimum.
- Adherence with treatment. Improvement is unlikely if patients do not adhere to treatment. Side-effects are a common cause.
- It is important to evaluate treatment outcome. The greater the level of depressive symptomatology following antidepressant treatment the higher the probability of relapse. The goal in treating the acute episode is to achieve remission
- Wrong diagnosis. If the antidepressant doesn’t work this option should be considered. Several somatic illnesses and medication can present with depressive symptoms.
Nevertheless it is estimated that 20-40% of patients with a major depressive episode do not show substantial clinical improvement to their first antidepressant treatment.
Staging methods to assess levels of treatment resistance in depression are being developed:
- The Antidepressant Treatment History form. A clinician rated instrument. This form is empirically validated via prospective treatment outcome reports. This form is mostly used with electroconvulsive therapy (ECT) outcome. There is debate about the influence of treatment resistance and efficacy of ECT. Some studies show a negative influence on ECT outcome of medication resistance other studies can’t find such an influence.
- Harvard Antidepressant Treatment History. Clinician rated instrument.
- Massachusetts General Hospital Treatment Response Questionnaire. Patient rated instrument. Advantage of this instrument is the absence of clinicians’ biases, particularly when treatment resistance is required for inclusion in a study.