An Indian OCD guideline puts a number on an adequate trial

The Indian Psychiatric Society has updated its clinical practice guideline for obsessive-compulsive disorder, replacing the 2017 edition. It is the work of one national society, not a global standard. It covers assessment, drug treatment, brain stimulation, neurosurgery, psychotherapy, management by phase of illness, comorbid conditions, pregnancy and lactation, children and older adults.

How long an adequate trial lasts

For medication, the guideline asks for at least 12 weeks of an SSRI or clomipramine before judging it, because the effect starts late. It quotes American Psychiatric Association advice: reach the maximum FDA-approved dose over 4–6 weeks, then hold it for another 6–8 weeks. Antipsychotic augmentation in low doses (risperidone 1–3 mg, aripiprazole 5–10 mg) needs at least 8 weeks. For psychotherapy, the standard is one-to-one, in-person CBT with exposure and response prevention: 12–20 sessions over 3–4 months.

The document adds that, in a meta-analysis of 17 randomised trials, SSRIs separated from placebo as early as 2 weeks, but early gains are not always clinically meaningful. It reports that 40–70% of patients show an adequate response to an SSRI trial, and 10–40% reach remission.

A clinician can use these figures as a checklist before speaking of resistance. Was the dose raised to the maximum tolerated? Was it held long enough? How many exposure sessions did the client actually attend, and how much of the practice between sessions was done? The guideline's own introduction notes that fewer than a third of people with OCD receive appropriate pharmacotherapy, and fewer still receive evidence-based psychotherapy.