Conversion disorder, also known as functional neurological symptom disorder (FND), is a psychiatric disorder characterized by symptoms affecting sensory or motor function. These signs and symptoms are inconsistent with patterns of known neurologic diseases or other medical conditions. Although conversion disorder has no organic basis, the symptoms significantly impact a patient’s ability to function. Moreover, the symptoms cannot be controlled at will and not considered to be feigned intentionally by the patient. The term “conversion disorder” was first mentioned in literature by Sigmund Freud (1856-1939). The Austrian neurologist and founder of psychoanalysis believed that functional symptoms that could not be explained by neurologic diseases or other underlying medical conditions reflected an unconscious conflict. In this context, the word "conversion" refers to the replacement of a somatic symptom with a repressed idea. The understanding of conversion disorder is still largely limited and continually evolving.
Psychological, social, and biological factors can all contribute to, precipitate, or perpetuate conversion disorder. Often, there is a trauma, adverse life event, or acute/chronic stressor preceding symptoms of conversion disorder. Many patients with conversion disorder are found to have a history of childhood abuse, both emotional and sexual. Other psychological factors contributing to conversion disorder include poor coping skills and internal psychological conflicts. Patients with conversion disorder are more likely to have certain psychiatric disorders (depression, anxiety, and personality disorders) than patients with known neurologic conditions. They are also more likely to have a history of multiple somatic complaints, including symptoms like generalized fatigue, weakness, or pain, without a known cause. Physical injury or actual neurologic illness (such as a stroke or migraine) may “trigger” the symptoms of conversion disorder. Less educated people, those of lower socioeconomic status, and patients living in developing or rural areas are more likely to develop conversion disorder. There are two major models or hypotheses for conversion disorder.
The hypotheses formulated to explain the etiology and the pathogenetic mechanisms of FND are manifold. For example, the role of microglia and neuroimmunity and, in turn, the altered control on synaptic plasticity have are theoretical explanations. These processes could explain the FND-associated motor dysfunctions.
The incidence of conversion disorder depends largely on the populations that studied. Akagi and House found that the average incidence of conversion disorder across varying geographic settings was approximately 4 to 12 per 100000 per year. Population-based case registries would place the rate of conversion disorder higher, at 50 per 100000 per year. The Scottish Neurologic Symptoms Study was a cohort study looking at 3781 individuals in an outpatient neurology setting; of these individuals, an estimated 5.6% had conversion disorder. Another analysis that was conducted by Perkin included 7836 individuals seen in the outpatient neurology setting. This research was a retrospective study, and it concluded that approximately 4% of patients had symptoms consistent with conversion disorder. However, this study took place in 1989. Research has revealed that adult women diagnosed with conversion disorder outnumber adult men in a ratio range from 2 to 1 to 10 to 1. Patients of lower socioeconomic class and with less education have higher incidences of conversion disorder. Race does not appear to be a factor. Studies have shown that conversion disorder in children is rare under age 5, and occurs most commonly during puberty and adolescence. The incidence of conversion disorder in children is also largely population-based; in one study conducted in Germany, found the rate of conversion disorder in the pediatric population was 0.2%. In another study conducted in Australia, the rate of conversion disorder in the pediatric population was 2.3 to 4.2 per 100000 per year. Over ten years of age, girls demonstrated a three times more likely chance to develop conversion disorder than boys.
Neurobiological models suggest that conversion disorder results from changes in higher-order cortical processing. The general, broad hypothesis is that frontal and subcortical areas of the brain may be activated by emotional stress, which then leads to input to inhibitory basal ganglia-thalamocortical circuits when then reduces conscious sensory or motor processing. There is not currently an abundance of studies looking at the neural mechanisms of conversion disorder with large sample sizes. Functional neuroimaging has helped shed some light on these mechanisms and will be a crucial tool in future studies. One study conducted by Spence et al. compared three patients with weakness secondary to conversion disorder with both normal controls and controls that researchers asked to feign weakness. The patients were asked to move a joystick while undergoing PET comparison. The patients with conversion disorder demonstrated decreased left dorsolateral prefrontal cortical activity when they attempted to move the affected limb. This study suggests that patients with conversion disorder are distinct from those that are feigning symptoms. The left dorsolateral prefrontal cortex has a role in volition and willed action. Another study conducted by Voon et al. looked at the relationship between emotion and symptom production in patients with conversion disorder. Researchers asked the patients to perform an emotional task, and functional MRI showed an abnormal correlation between activation of the amygdala and the supplementary motor area.
Obtaining an appropriate history is a crucial factor in conversion disorder. It is crucial to make the patient feel comfortable and to encourage them to share their symptoms, but also their story. One method to consider is the creation of a list of the patient’s symptoms at the initial visit; allow the patient to list all symptoms that they have been experiencing recently. This initial step is essential, both so that one can document any subtle changes in symptoms throughout the illness, but also to see if the patient lists multiple somatic symptoms. It is essential to ask the patient for a list of symptoms for which they have received treatment previously, or suspected neurologic diagnoses. The clinician should focus on gathering details, such as the time-frame of symptoms and context. Without revealing the suspected diagnosis, it is important to ask about recent events or stressors in the patient’s life, and for a complete psychiatric history. Family history should also include psychiatric components. The clinician may wait until the end of the interview to ask for psychiatric history. If the patient has experienced similar symptoms in the past, what was their diagnosis, and how were they treated? Patients with a history of conversion disorder are more likely to have repeat episodes, even without a past diagnosis. These questions can also help shed light on the patient’s view of other providers, and to show which specialists they have seen and what work-up they have had. Involving the patient is crucial to building rapport; ask them what they feel is going on. Instead of focusing on what the patient cannot do at the time of the interview, ask them to describe the last time that they remember being symptom-free, and ask them to describe what a typical day looks like for them.
Conversion disorder cannot truly be considered a diagnosis of exclusion, but diagnosis relies on the clinician to exclude major neurologic diseases and to look for inconsistencies on an exam, as well as clinical signs and symptoms that are not characteristic of organic disorders. Inconsistent symptoms, negative labs/imaging, and/or a significant psychiatric disorder are reliable indicators of conversion disorder, but the clinician should still exclude all other organic disorders with a thorough exam. Also, patients with conversion disorder may have comorbid neurologic disorders, which may make the diagnosis more difficult.
The Diagnostic and Statistical Manual of Mental Disorders, 5 edition (DSM-5) categorizes conversion disorder as part of the “somatic symptom and related disorders.” In previous editions of the DSM, clear psychologic comorbidities were a required part of the diagnosis, as well as the ability to show that the symptoms were not intentionally produced. The DSM-5 has also removed “la belle indifférence” (a patient’s apparent indifference to their condition) as a diagnostic criterion. These are now considered features that support the diagnosis of conversion disorder. Other supporting features include associated dissociative symptoms and recent psychological or physical trauma.
The diagnostic criteria for conversion disorder, according to the DSM-5, are as follows:
The presence of symptoms defines an acute episode of conversion disorder for less than six months, and persistent conversion disorder includes the presence of symptoms for greater than six months. Conversion disorder can also have the specifier of with or without the psychological stressor. The DSM-5 recognizes several subtypes of conversion disorder, as listed below. There are many ways to differentiate between organic disorders and these subtypes of conversion disorder.
Visual disturbances – In general, visual disturbances are very common in conversion disorder. If a patient exhibits complete blindness, they are more likely to have factitious symptoms. In conversion disorder, the patient’s pupillary reflex is present. We would expect a recent diagnosis of true blindness to result in the patient having some difficulty maneuvering, and perhaps increased incidence of injury, with superficial bruising/wounds; this is not present in conversion disorder. The following tests can aid in proper diagnosis:
Olfactory or hearing disturbances are less common than visual disturbances. Patients with conversion disorder typically report anosmia or deafness. Patients with anosmia can take a taste test, in which they will usually indicate a normal sense of taste. In true cases of anosmia, patients have a decreased sense of taste or exhibit some signs of nutritional deficiency/malnourishment. In patients with symptoms of deafness, the examiner can attempt to confront the patient with a loud sound, which will usually elicit a blink or some form of the startle response.
The primary tools used to make the diagnosis of conversion disorder are the history and physical exam; however, laboratory studies or imaging may be required to rule out underlying medical conditions. The studies ordered are highly dependent on the nature of the patient’s symptoms and their initial presentation. For example, patients that present with psychogenic nonepileptic seizures may undergo electroencephalogram to show a lack of true seizure activity, or they may have laboratory studies such as prolactin or creatine phosphokinase drawn to help differentiate their condition from an epileptic seizure. A vast majority of patients presenting with weakness as a primary symptom will undergo tests such as electromyography or magnetic resonance imaging. Studies may also be ordered for patients with possible comorbid diagnoses.
The first step in the treatment of conversion disorder involves an effective presentation of the diagnosis to the patient. General recommendations are that the clinician does not reveal the diagnosis during the first encounter. Instead, it is essential to build a strong therapeutic alliance with the patient. The clinician should ask the patient what they feel is wrong with them and encourage discussion of their feelings regarding their symptoms. During subsequent encounters, several important points merit focus:
Psychotherapy is the first-line treatment in most cases of conversion disorder. Different types of therapy can be useful, but the most effective throughout literature seems to be cognitive-behavioral therapy (CBT). CBT works by looking at the way someone thinks and feels about a situation and how that influences their behavior. Predisposing factors can be analyzed, and patients should focus on improving their communication and ability to express emotions properly. Goldstein and his colleagues conducted one study that highlights the efficacy of CBT to treat conversion disorder; although it used a small sample size, the study showed that CBT successfully reduced dissociative seizures frequency by at least 50%. Other types of therapy that may prove helpful include psychodynamic psychotherapy (individualized and best for patients that have already accepted that their symptoms may be secondary to past trauma), group therapy (this may help patients learn from and support each other), and family therapy (this may help improve communication). Furthermore, hypnotherapy can ameliorate functioning and physical symptoms from conversion disorder, even in particularly severe cases. These approaches seem to be effective, especially in the case of comorbidities, such as chronic pain conditions. However, hypnosis is considered a second-line treatment that may be helpful for patients with speech symptoms or sensory loss.
Another first-line treatment that clinicians should offer in conjunction with CBT is physical therapy. This approach is more useful for functional motor symptoms and helps the patient feel as though their clinical team takes their symptoms seriously. The therapist can usually decrease functional motor symptoms by encouraging normal movements and slowly working on more complex tasks at each session. Physical therapy can also prevent secondary weakness or true deficit caused by the patient’s functional motor symptoms. Hypnosis is a second-line treatment that may be helpful for patients with speech symptoms or sensory loss.
Pharmacotherapy is most effective when there is a comorbid mental illness, such as anxiety or depression. Medications such as antidepressants, anxiolytics, or mood stabilizers would be chosen based on the underlying illness. Some studies have suggested that antidepressants, specifically those that target pain (such as serotonin and norepinephrine reuptake inhibitors), may be helpful for certain symptoms of conversion disorder, even if underlying mental illness is not clear. Among the pharmacological approaches, several investigations have taken place to evaluate the effects of antipsychotics. Recent studies suggest that quetiapine and haloperidol have a comparable effect in relieving the patients from conversion disorder symptoms; however, the occurrence of extrapyramidal symptoms seems to be significantly lower with the atypical antipsychotic quetiapine.
Transmagnetic stimulation (TMS) may be beneficial for patients with conversion disorder, though there have been no published, control studies. There are hypotheses that TMS may have neuromodulating effects that can change beliefs or expectations about symptoms. There have been mixed reviews on paradoxical intention treatment, which involves asking patients to engage in unwanted behavior intentionally, which elicits symptoms of conversion disorder. Some critics feel that this is harmful to the patient-clinician relationship, and others believe that it may help the patient realize that specific thoughts or situations trigger their symptoms. One of the most critical aspects of treatment in conversion disorder is frequent follow-up appointments with all involved clinicians. Frequent follow-up prevents the patient from visiting other facilities such as urgent care or the emergency room.
Several psychiatric disorders are included in the differential diagnosis for conversion disorder.
There is a multitude of general medical conditions or neurologic disorders that may share features with those of conversion disorder; this largely depends on the specific presenting symptom that the patient displays. Some common medical conditions included in the differential are as follows:
In strokes, spinal disorders, and movement disorders, the essential exam findings in conversion disorder are inconsistencies with anatomical or neurologic patterns.
The general prognosis for conversion disorder is generally poor; however, this is dependent on multiple factors. Factors that promote a good prognosis include sudden onset, early diagnosis, short duration of symptoms, lack of comorbid psychiatric disorders (especially personality disorders), identifiable stressors, and a positive patient-clinician relationship. Patients with a greater number of physical symptoms of poor physical functioning prior to diagnosis have an increased chance of a poor outcome.
The complications of conversion disorder include permanent disability and impaired quality of life. Some patients become lost to follow-up, and other patients do not complete treatment as advised. One study found that disability rates and impairment of quality of life were similar in patients with functional movement symptoms when compared to Parkinson disease. Another study found that patients with symptoms of paralysis had rates of disability similar to patients with multiple sclerosis. Overall, patients with psychogenic symptoms have comparable rates of physical disability and higher rates of psychological disability than patients with actual neurologic disorders.
As aforementioned, patient education is a large aspect of the treatment for conversion disorder. It is essential to give patients resources that they can review with their families. There are national conversion disorder support groups for the patient. The clinician should attempt to meet with the patient’s family separately to discuss positive reinforcement skills. They should be encouraged to focus on the legitimacy of the patient’s symptoms, rather than telling them that nothing is wrong with them. Families can provide tremendous support and may also be able to help the clinician identify specific stressors for the patient’s symptoms. Families can also help ensure that the patient attends follow-up appointments. They can become involved in family therapy. It is also crucial to realize that the diagnosis of conversion disorder may put additional stress on a patient’s family. They should be encouraged to attend support groups for individuals that have family members with mental illness.
All cases of conversion disorder can benefit from an interprofessional team approach. Of note, interprofessional chronic pain rehabilitation programs that represent multidimensional and tailored functional restoration interventions studied for chronic pain appear to be effective also as an approach for FND. This disorder, indeed, requires a multi-professional strategy with effective communication between primary care physicians, psychiatrists, and psychologists. Psychiatric nurses are often involved in care and should not confront patients. They monitor the patients and provide education when appropriate. When prescribing medications, pharmacists review the agents chosen, verify doses, and provide information to the patient and their family about the importance of compliance and side effects. Both nursing and pharmacy must report any concerns or issues encountered to the clinicians on the team; this collaborative interprofessional approach will result in improved patient outcomes with fewer adverse effects. [Level 5]
Many patients will also have a neurologist, or other specialists, depending on the subtype of their symptoms. The providers involved in the patient’s care need to come to a consensus on an effective presentation of the diagnosis and a clear, multi-faceted treatment plan. Ineffective communication can lead to a weak patient-clinician relationship, poor prognosis, and relapse of symptoms. Patients with motor symptoms benefit strongly from the inclusion of a physical therapist into the treatment team. Patients with severe cases of conversion disorder involving debilitating physical and psychological symptoms, or those who are not responding to initial treatments, may benefit from inpatient treatment with an interprofessional approach. [Level 3]
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