Faulty Circuits: OCD and the Brain
Obsessive Compulsive Disorder is the 4th most common mental health condition in the world, and affects over 50 million sufferers. 21st century technology is now unlocking the secrets of neuroanatomy, giving us a glimpse into what makes an OCD brain tick.
Obsessive-Compulsive Disorder, has been with us throughout our history, from the blasphemers beset with devils in the Dark-Ages, to the caricatures of 21st century film and television. Emerging as a distinct diagnosis in the 1840’s, it has divided opinion over its cause. Victorian psychiatrists considered it a hereditary disease of the ‘nerves,’ Edwardian psychoanalysts claimed it as a psychological defence mechanism aiming to suppress latent aggression, in today’s world we have almost come full circle, once more scientists are labelling OCD as a problem within the brain. To understand it, we first need a lesson in Neuroanatomy.
Greek for ‘little chamber’ the thalamus appears as two symmetrical almonds located deep in the cerebrum. Thought to be the brains switchboard it relays sensory data to the cortex, as well as regulating sleep-cycles, motor-control, and alertness. The Thalamus as a switchboard, takes incoming calls from the outside world, and then decides which department to put them through to.
Resembling a seashell, tightly wrapped around the Thalamus, the Striatum is primarily concerned with transmitting complex data to different parts of the brain. Latin for ‘furrow,’ if the Thalamus is the switchboard of the brain then the striatum is the wiring which allows messages to come through.
The Orbifrontal Cortex
One of the most mysterious areas of the Prefrontal Cortex is the Orbifrontal cortex. It is thought to be heavily involved in executive decision making, and determining the value of positive or negative experiences. In scientific terms it is the system that deals with environmental ‘reinforcers,’ and behavioural conditioning. If scientists are right, it is one of the key parts of the higher-order brain, and one of the most important tools in adaptive learning; helping us decide whether we should keep behaving in a certain way because of the reward, or avoid it because of punishment. For this reason it is rather like a manager of a messaging service.
The problem is these three structures are interconnected and appear be malfunctioning in the brains of individuals with Obsessive-Compulsive Disorder. The ‘vicious cycle’ metaphor, could not be more apt, because all three structures work together in a complex feedback system. This takes the form of an electrical ‘loop’. The cortico–striato–thalamo–cortical’ (CSTC) circuit is what creates the broken record effect of OCD.
Yet what is the difference between the OCD brains and their “normal” counterparts? For the last thirty years brain-scan’s have consistently shown, the feedback loops of those suffering obsessions and compulsions are overactive. While the exact mechanism is unclear we know that people with OCD are trapped in a loop of sensory relay and misinterpretation.
In other words, it appears, sensory data travelling through the wiring of the Striatum becomes corrupted. This in turn leads the Thalamus switchboard to receive an unclear message. The Thalamus, then relays the unclear message to the Cerebral Cortex. Because the message is unclear, the brain, becomes “overexcited” and the threat of harm becomes terribly exaggerated. Thoughts become “trapped” in the feedback loop and become obsessions. In turn the orbifrontal cortex is activated. Its aim is to judge the corrupted message, but misapprehends the supposed harm, and causes us to act, in maladaptive ways. These become compulsions. The anxiety which is the raw energy of OCD is in part created by this faulty feedback loop.
A Point of Contention
One of the most bitter disputes in mental health has been between whether brain abnormalities are cause or consequence of OCD. Neuropsychiatrists claim that people with OCD have brains which are faulty to begin with. Psychologists, argue our thoughts and behaviours leave an indelible mark on the brains chemistry, and change the circuits.
As well as this dispute, we are also left with the specific content of obsessions. Ranging from aggressive thoughts of violence, to fears about germs or dirt; it appears rumination’s take many forms. Traditional psychologists will argue this is because thoughts are related to the individual in question. Behaviouralists on the other hand, will say obsessions are actually uniform across cultures, and are meaningless. Overall, there is no sure answer for what causes OCD, but the good news is it can be treated.
One of the most remarkable discoveries about OCD is that the brains hardwiring can be reconfigured. Brain-scans have demonstrated that the feedback loops of CSTC circuit, can be restored to normal function. This means the faulty switchboard of the Thalamus, the corrupted wires of the Striatum, and the overzealous management of the Orbifrontal Cortex can all return to baseline normal.
Reconfiguration can be achieved via medication, but even more incredibly through targeted intervention in the form of Exposure therapy. If the brains messaging service is broken, this is the equivalent of drafting in a repair team who can fix it.
However, it is also true OCD is often a lifelong impairment. Without consistent practise there is always a a biological susceptibility to fall back into the damaged ‘loop.’ Sufferers may have to combine medication with CBT, if they are to prevail. The feedback system can be fixed but it is needs routine maintenance.
Nevertheless we have every reason to be hopeful about OCD. If psychotherapy doesn’t work, medication will. The UK has national specialist inpatient and outpatient treatment centres as does the USA and Europe. The recent innovations in neuroanatomy combined with the tried and tested methods of psychotherapy, mean sufferers now have a chance to get better. If these finding are anything to go by, the feedback is positive.