The broader benefits of DBS for refractory OCD

We write having read the informative Viewpoint by Mosley et al. (2021) which, in making a case for the acceptance of deep-brain stimulation (DBS) for refractory obsessive-compulsive disorder (OCD), provides some interesting insights as it reviews the findings of four randomised controlled trials that support the administration of this intervention. The article provides a brief overview of recent data before making a compelling argument as to how the treatment can be offered in a regulated and measured way to those in need, and why both legislative barriers and funding opportunities need to be opened for this initiative.

We write specifically and particularly enthusiastically, however, because OCD is arguably one of the best defined phenomenologies in clinical psychiatry, and as a disorder has one of the clearest mechanistic explanations rooted in the neuroanatomy of the brain. In other words, it is perhaps one of our best models instantiating qualia of the mind in the physicality of neural structures. And as per the figures in Mosely et al.’s article, it exemplifies the synergy of cognitive neuroscience involving neurosurgery, neuropathology, modern neuroimaging and psychiatric expertise. Elevating it further still, however, this collaboration yields an enduring therapeutic benefit in one of the most disabling of medical disorders (Fenoy et al., 2022). But this is not all; this is an opportunity to understand, innovate and explore further, particularly in relation to potential predictors of outcome such as duration of illness, comorbidity and symptom subtype (Alonso et al., 2015).

The intriguing observations, noted only briefly, include the dissociability of effects on mood and cognitive flexibility, which depend on stimulation site and other parameters. The fact that stimulation-dependent impulsivity and hypomania can be induced, and that withdrawal or modification of parameters can lead to lowering of mood, signals that there are potential avenues of future research that must be explored.

The article by Mosley and colleagues is particularly relevant as a large number of disorders are at the intersection of psychiatry and neurology with neuropsychiatric manifestations. As more causal pathways are identified which are shared across the spectrum of neurological and psychiatric disorders, this might also stimulate a discussion whether to imbed aspects of neurological training into psychiatry and vice versa. Partial reintegration of the two disciplines, especially in the undergraduate/graduate training and in research, could strengthen both.

In sum, we are in favour of the suggestions made by the group regarding how patients should be assessed, and monitored, and how they should be managed ethically with both a sense of duty and fairness – to provide these troubled patients an opportunity for relief. However, while lending our support to these requests, we also note that this intervention needs to be distinguished from other forms of brain stimulation, where there is no such specificity of action. A clear distinction also needs to be made between DBS and psychosurgery, where the changes involve ablation of tissue and are essentially irreversible.