Are Randomized Control Trials suited for Mental Health research?

Here are some limitations of using Randomized Control Trials (RCT) for Mental Health (MH) research.

1. In the selection of people to RCTs, one needs to include subjects of a single condition or diagnostic category. However, in psychiatry the diagnosis can be unstable, changing, apart from secondary conditions, undiagnosed comorbid conditions.
2. This also implies that the external validity of the RCT results are limited for MH.
3. Outcomes valued by patients are rarely measured in RCTs which results in medicine compliance issues. This results in drug failure in practice.
4. Individual variability in clinical outcomes is a feature of psychiatric interventions. But these are masked by group mean.
5. To make the groups more homogenous minorities are excluded from subject pool limiting the external validity of the findings.
6. The assumption in RCT is that any intervention can be treated as a drug. However, outcomes of psychological interventions are subjective.
7. Randomization in CBT limits the efficacy of the treatment. So RCT of CBT is not appropriate.
8. RCT undervalues interventions for which outcomes are difficult to measure e.g. general wellbeing.
9. It is not always possible to randomly allocate subjects to different treatment groups in mental health research settings especially if the subjects are in crisis. For instance, it is not always possible to give a subject placebo especially if the subjects are in crisis.