Depersonalization is a dissociative disorder in which an individual experiences a disconnection between body and self. Although this type of mental disorder is mainly the product of perceptual and cognitive dysfunction, symptoms of depersonalization disorder can sometimes be used to diagnose more severe mental illnesses such as schizophrenia.
Symptoms of Depersonalization Disorder
Although depersonalization disorder is classified as a disorder in itself, it is often seen as a symptom of a more severe and multi-symptom psychotic disorder. Depersonalization disorder is dominated by the sensory experience of dissociation from the body. Patients suffering from depersonalization disorder feel as if their consciousness and body are two separate entities and may experience this symptom in sporadic episodes or chronically. While the experience of depersonalization can be disorienting, patients are not delusional and are fully aware of their situation during an episode.
Functional magnetic resonance imaging has been used to study emotional dissociation in patients with depersonalization disorder. Studies comparing participants’ neurological reactions to neutral and emotionally intense scenes have shown that while patients with depersonalization disorder are fully aware of the scene (they are able to describe it in perfect detail and understand the context and meaning), they show no emotional reaction to emotionally explicit stimuli as proven by inactivity of the insular cortex which is related to emotional regulation.
The Etiology of Depersonalization Disorder
Depersonalization disorder may be caused by a hypoactive sympathetic nervous system. Electrodermal response studies and measurement of blood flow through the forearm are used to study the activity level of the sympathetic nervous system. By measuring blood flow and the skin’s conduction of electricity based on the amount of moisture present, researchers have shown that patients suffering from depersonalization disorder have low basal recordings and skin conductance, conveying that the sympathetic nervous system’s arousal level is poor.
Another theory about the etiology of depersonalization disorder states that symptoms are caused by dysfunction in the prefrontal cortex, mainly characterized by inhibition of certain structures. Researchers rationalize this theory by stating that mental inhibitory actions serve protective purposes which makes sense on both a psychological and evolutionary perspective. This theory makes sense psychologically because dissociative disorders are self-preserving and protective in nature. Patients with depersonalization disorder feel disconnected from their bodies, and while that sensation in itself is abnormal, they retain full consciousness and are aware of both their body and their mind- they just don’t recognize them as a synchronized unit. Therefore, the theory makes sense on an evolutionary level because hyperactive autonomic responses can be distracting in a life-or-death situation. An underactive sympathetic nervous system however, would allow the individual to be calm and calculating on a conscious level, while preserving the body’s ability to act alertly on a physical level.
Since depersonalization disorder is characterized by emotional dissociation, there is an etiological theory related specifically to this symptom. When presented with emotionally charged stimulus, functional magnetic resonance imaging shows that patients suffering from depersonalization disorder fail to achieve activation of their insular cortex. It is theorized that this is due to low levels of basal norepinephrine. This neurotransmitter is found in the sympathetic nervous system and is responsible for regulating memory formation and retention, arousal, and energy levels. Norepinephrine is a catalyst in the kickoff of autonomic responses during the fight or flight response. The norepinephrine theory is complimentary to the prefrontal cortex dysfunction theory of depersonalization disorder as adequate levels of norepinephrine are needed for normally functioning sympathetic nervous system response.
The Pathophysiology of Depersonalization Disorder
The functional changes in a patient diagnosed with depersonalization disorder occur on a neurobiological level. Neurotransmitter dysfunction and neurostructural damage account for the symptoms of detachment from consciousness, emotional apathy, and depression. Neurotransmitter dysfunction is specific to a decrease in the production of norepinephrine while neurostructural damage is localized to the temporal lobe. Studies in this area have revealed that stimulation of the medial temporal gyrus produces depersonalization-like symptoms. Other research supports the theory of temporal lobe damage in depersonalization disorder and studies on patients diagnosed with the disorder reveal frontotemporal activation on the left hemisphere of the brain.
Treatment of Depersonalization Disorder
Since not much is known about the exact molecular cause of depersonalization disorder, it is often treated pharmacologically like depression. The correlation between depersonalization disorder and norepinephrine have caused physicians to treat it with dopamine, norepinephrine, and serotonin reuptake inhibitors. Another option is psychotherapy, however since the etiology of the disorder is not entirely of psychological cause, many patients are treated with a combination of psychotherapy and medication.
Depersonalization and Schizophrenia
I mentioned above that although depersonalization disorder is classified as a disorder in itself, it is often listed as a symptom of a more complex psychological disorder, usually schizophrenia. The reason that it has prevailed as a disorder in its own right has to do with research on both depersonalization disorder and schizophrenia. While both disorders have similar biological and environmental causes, there are some important differences. On a biochemical level, schizophrenia is mostly associated with dopamine and serotonin, although GABA and acetylcholine are also involved. Depersonalization disorder is mostly associated with the neurotransmitter norepinephrine.
Depersonalization disorder is classified as a symptom of schizophrenia mainly because the latter has shown proven ties to significant structural damage, while the former shows ties to the prefrontal cortex on the left hemisphere. Since the neurostructural damage seen in schizophrenia is so widespread, parts of the brain responsible for symptoms of depersonalization disorder are bound to be affected. This also explains why depersonalization is not always a symptom of schizophrenia as its presence as a symptom would depend on the extent of structural damage to the patient’s brain. Therefore, the fact that depersonalization is a symptom of schizophrenia is simply due to the overlap in neurostructural characteristics between both disorders.