Mental health issues are more common than many people think. More than a billion people across the world are affected by a psychiatric disorder each year. Most of these are common and treatable. But rare mental health disorders can catch even experienced medical and mental health professionals off-guard.
People may endure symptoms for long periods because of the difficulty of getting an accurate diagnosis. Here are some of the least common mental health disorders as recognized by the American Psychiatric Association’s (APA’s) Diagnostic and Statistical Manual of Mental Disorders (DSM-V).
A delusion is a fixed but incorrect belief based on their interpretation of reality. The individual remains firm in their belief despite evidence against it. Delusions can also appear as a symptom of other conditions, such as schizophrenia or body dysmorphic disorder. Delusional content can center on ordinary situations (imagining someone is constantly calling on the phone), or bizarre acts that defy reality (birds beginning to speak to them).
When an individual has no history of schizophrenia or has experienced non-bizarre delusions for at least one month, they may be diagnosed with delusional disorder.
According to the APA, delusional disorder may affect .02% of the general population, or one out of every 5,000 people. The most common type of delusion theme is persecution, when an individual erroneously believes someone is tracking or harassing them.
Treating delusional disorder can be challenging, since the individual fully believes the delusion to be true. But low levels of antipsychotic medication and a good relationship with one’s therapist can, in many cases, be significantly beneficial.
When left untreated, delusional disorder may lead to depression, social isolation, or legal issues from pursuing people associated with their delusions.
Conversion disorder is a loss of function in a part of the body that can’t be explained by physical disease or injury. It affects an individual’s senses or motor functions. This disorder can present itself through such symptoms as sudden blindness or one’s paralysis.
The individual doesn’t appear to be faking or in control of the symptoms. They are very real and upsetting to the individual. Before they can be diagnosed with conversion disorder, medical providers must do a thorough exam and show clinical evidence that no biological problem is behind the symptoms. Instead, the cause may stem from a psychological conflict or emotional trigger. After experiencing a stressful event, for instance, an individual’s emotional distress can be converted into a physical ailment.
Anxiety, depression, and personality disorders often occur together with conversion disorder.
The DSM-V states that 2-5 of every 100,000 individuals contends with conversion disorder. However, this estimate can vary widely, depending on the group of people being studied.
Treatment begins when the medical provider establishes trust with the individual, affirming their distress before explaining the conversion diagnosis. Cognitive-behavioral therapy in particular has been found to be effective when treating this condition.
Selective mutism occurs when an individual is physically unable to speak in certain social settings. It is an uncommon mental disorder most commonly found in children under five years of age. A child with this condition can speak normally most of the time but is consistently unable to in specific settings. This is not an unwillingness to speak, but instead a physical inability to produce speech. Most children with this disorder also experience intense social fears.
Selective mutism may be diagnosed when this pattern lasts for at least a month. An individual who’s been through trauma may show symptoms similar to selective mutism, and as such, healthcare providers must consider this before making a diagnosis.
Selective mutism may develop in about .03-.79% of the general population.
Without treatment, the condition can worsen and affect a child’s functioning in school, social situations, and other settings. Symptoms may continue into adolescence and adulthood.
Treatment usually involves work on behavioral changes, psychotherapy and some use of medications. Since it is a fairly new diagnosis, more research is needed to understand it and the effectiveness of different treatments.
Postpartum depression is a common mood disorder affecting 10-15% of mothers giving birth every year. A rare version of this develops with psychotic symptoms, affecting five out of every 1,000 mothers. It is considered a rare and potentially harmful psychiatric emergency. Untreated psychosis can lead mothers to harm themselves or their babies, so a mother diagnosed with postpartum psychosis needs urgent hospitalization and treatment.
Symptoms of this condition often develop within the first two weeks after giving birth and may include bizarre delusions, confusion, and coming in and out of consciousness. A mother may also show mood disorder symptoms, such as irritability or depression. The majority of delusions exhibited as part of postpartum psychosis involve feelings of persecution.
Abnormal thoughts and behaviors are red flags for postpartum psychosis. Another warning sign is a mother not wanting or being unable to sleep when given the opportunity.
First-time mothers and mothers with a history of bipolar disorder appear to be at greater risk of developing postpartum psychosis.
Lithium and antipsychotic medications are the primary treatment options for this condition.
Heavy illicit substance use can sometimes cause an individual to have panic attacks and anxiety symptoms, either while under the influence or while going through withdrawal. For a small number of people, these symptoms become overwhelming and require treatment. When an individual shows distressing symptoms that don’t fit a specific anxiety condition, they may be diagnosed with substance-induced anxiety disorder.
It is not clear how often this disorder occurs, but it has been found to be as low as .002%, over a 12-month period.
Substance-induced anxiety can be difficult to diagnose, mainly since anxiety and substance use often occur together. Abstinence and addiction treatment can help clarify the diagnosis.
One reason rare mental illnesses stand out is due to their unusual symptom combinations. However, that does not show the whole picture: many people cope with more common conditions, such as anxiety or depression, every day, making common disorders a much wider social issue. Mental health treatments have also been responding to comorbidity between mental health conditions, with such treatments as Deep TMS being FDA-cleared to treat both depression and anxiety symptoms within depression.
The more people talk about mental health, openly and authentically, the easier it may be to recognize and support people with mental health issues, rare and common alike.