What is the hardest mental illness to treat?


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Page last updated: 10/10/2022

What is the hardest mental illness to treat?

In this guide, we will discuss “What is the hardest mental illness to treat” , some of the known treatments for borderline personality disorder, what are mental illnesses, why do people develop mental illnesses and a top 15 of the strangest/scariest mental illnesses.

What is the hardest mental illness to treat?

If you wonder ‘What is the hardest mental illness to treat?’ we can tell you that there may be varied opinions. However, borderline personality disorder has been viewed as very difficult to treat. Evidence-based treatment has shown how many people living with Borderline Personality Disorder seem to experience less severe symptoms, improved functioning and quality of life.

However, let’s understand first what is Borderline Personality Disorder often referred to as BPD. According to the National Institute of Mental Health:

“Borderline personality disorder is an illness marked by an ongoing pattern of varying moods, self-image, and behavior. These symptoms often result in impulsive actions and problems in relationships with other people. A person with borderline personality disorder may experience episodes of anger, depression, and anxiety that may last from a few hours to days. Recognizable symptoms typically show up during adolescence (teenage years) or early adulthood, but early symptoms of the illness can occur during childhood.”

Moreover, even if living with BPD can be considered difficult due to having unstable relationships, emotional reactivity and dysregulation, among other characteristics, many people with BPD don’t even know they have it. This is why BPD is one of the most commonly misdiagnosed mental health conditions besides being one of the hardest mental illnesses to treat. 

One of the reasons why it goes misdiagnosed is because BPD looks like so many other mental illnesses such as depression, anxiety, post-traumatic stress disorder, bipolar disorder, eating disorders, among others. Evidence has indicated that BPD is commonly misdiagnosed as Bipolar Disorder Type 2, most likely due to some similar symptoms. However, getting the correct diagnosis is crucial to find the appropriate treatment.

Known treatments for Borderline Personality Disorder

Some of the most effective treatments for BPD are:

  • Dialectical Behavior Therapy (DBT) 
  • Transference-Focused Therapy (TFP)
  • Mentalization-based Therapy (MBT)
  • Cognitive Behavioral Therapy (CBT)
  • Schema-focused therapy
  • Systems training for emotional predictability and problem-solving (STEPPS)

As indicated by the National Institute of  Mental Health, specifically referring to DBT, “was developed for individuals with borderline personality disorder, uses concepts of mindfulness and acceptance or being aware of and attentive to the current situation and emotional state. DBT also teaches skills to control intense emotions, reduce self-destructive behaviors, and improve relationships.”

Even though BPD is considered a hard mental illness to treat, there are several valid treatment approaches including not only psychotherapy but also medication, often used to treat other associated mental health conditions such as depression, anxiety disorder or bipolar disorder. With a good psychiatric management, people with BPD can manage the symptoms and live their regular lives. However, consider that there is actually no cure for BPD and this is also a fact for many mental illnesses. 

What is the hardest mental illness to treat?

What are mental illnesses?

The misconception here is to believe mental illnesses can come and go as if we were talking about a cold or flu virus. Just like any other physical illness, mental illnesses can manifest many different symptoms and range in severity. They have the ability to affect people in different ways and not everyone is likely to get the same symptoms every time. However, it is believed all mental illnesses can be treated but some of them can become more challenging than the other.

There are several types of mental illnesses and each one has its classifications. For instance, when we talk about anxiety disorders we can find a number of conditions such as phobias, social anxiety disorder, Generalized Anxiety Disorder, Panic Disorder, Separation Anxiety, etc.

In contrast, when we for example talk about personality disorders we can find:

  • Cluster A personality disorders: paranoid personality disorder, schizoid personality disorder and schizotypal personality disorder.
  • Cluster B personality disorders: Antisocial Personality Disorder, Borderline Personality Disorder, Histrionic Personality Disorder and Narcissistic Personality Disorder.
  • Cluster C personality disorders: Avoidant Personality Disorder, Dependent Personality Disorder and Obsessive-Compulsive Personality Disorder.

However, don’t think mental health professionals know them all by heart or somehow learned them all at University. The truth is that to be able to diagnose a mental illness there are a series of diagnostic manuals to help us assess, evaluate and diagnose someone depending on the symptoms they manifest. The most commonly used by professionals are the DSM-5 (in its latest version) and the ICD-10. 

Why do people develop mental illnesses?

There are many factors associated with the risk of developing a mental illness. For instance, if we specifically talk about personality disorders, we can’t determine the precise cause but factors that increase the risk of developing a personality disorder include:

  • Family history of personality disorders or other mental health illnesses. 
  • Being in an abusive, unstable, chaotic environment during childhood.
  • Being diagnosed with childhood conduct disorder.
  • Changes in your brain chemistry and/or structure.

Moreover, many scientists and researchers have indicated that genes may have something to do with developing a personality disorder such as BPD. For instance, certain personality traits that are passed from your parents to you genetically are said to put you at a higher risk of developing personality disorders. 

However, we can’t just blame it on genetics alone. As we have mentioned, your environment can contribute also to increasing the risk. For example, your experiences, the surroundings you grew up in, traumatic events that occurred and even relationships with family members and others can make you vulnerable to developing a personality disorder. Consequently, we are talking about genes plus the environment and certain triggers. 

If you believe you may have a mental illness, make sure to see a mental health professional for a proper assessment and diagnosis of your condition. This helps not only to get an accurate diagnosis but also get the possibility to evaluate your treatment options and start as early as possible. 

Top 15 of the strangest/scariest disorders of all time

Here is a top 15 of the strangest and/or scariest disorders of all time. We all constantly hear about depression or anxiety but there are many other disorders you may have never heard of. According to the website onlinepsychologydegree.info, here are 15 of them:

  • Alice in Wonderland Syndrome (also known as Todd Syndrome)
  • Alien Hand Syndrome
  • Apotemnophilia (also known as Body Integrity Disorder and Amputee Identity Disorder)
  • Boanthropy
  • Capgras Delusion
  • Clinical Lycanthropy
  • Cotard Delusion
  • Diogenes Syndrome (simply known as ‘hoarding’)
  • Dissociative Identity Disorder (known as Multiple Personality Disorder)
  • Factitious Disorder
  • Kluver-Busy Syndrome
  • Obsessive Compulsive Disorder
  • Paris Syndrome
  • Reduplicative Amnesia
  • Stendhal Syndrome

When you read some of them you might think ‘that really exists?’ and the answer is Yes. In fact, you may have even heard of Dissociative Identity Disorder, from the movie ‘Split’ where actor James Mcavoy gave life to a character that had 23 distinct personalities. Moreover, you may have heard of Obsessive Compulsive Disorder from series like ‘Monk’ who is a brilliant former San Francisco detective who now consults the police as a private consultant that battles with OCD, or the classic ‘As Good as It Gets’ with Star Actor Jack Nicholson. 

Why is this blog about What is the hardest mental illness to treat important?

We have mentioned in this blog how BPD seems to be the hardest mental illness to treat although there are many challenging disorders according to mental health professionals there always seems to be a treatment to help people live their lives as normal as possible. However, having a treatment for an specific condition doesn’t mean it is the ultimate cure since some of the conditions we have mentioned do not have a known cure but a treatment to manage the symptoms. 

Also, we talked about how there are many mental illnesses and disorders already specified and classified into the mental health manuals most professionals used to diagnose such conditions. Moreover, we saw how most of the mental illnesses and specifically the case of personality disorders there are some risk factors associated with developing the disorder such as genetic makeup and environment (mostly a combination of both). Finally, we mentioned some of the strangest disorders there are out there, you haven’t probably heard of or those that are not as common as depression or anxiety. 

Please feel free to leave any comments or thoughts about the content of this article!

Frequently Asked Questions (FAQs) about What is the hardest mental illness to treat

What is the hardest mental illness to live with?

Some experts believe that personality disorders are among the most difficult forms of mental illness to live with and treat. What happens most of the time is that people living with these disorders don’t really seek help because they are able to function on a daily basis. 

What is the most painful mental illness?

Some experts believe one of the most painful mental illnesses is Borderline personality disorder since it can produce the most intense emotional pain, agony, and distress for those suffering from this condition. Some studies have even found how people living with BPD experience chronic and significant emotional pain and mental agony. 

What is the most treatable mental illness?

One of the most treatable mental illnesses are anxiety disorders. People suffering from anxiety disorders experience unrealistic fears, excessive worry and even flashback from past trauma leading to being easily startled, having sleep disturbances, intense tension and ritualistic behaviors.

What is considered the most debilitating mental disorder?

Some experts consider the most debilitating mental disorder to be schizophrenia since it is by far the most disabling of the array of mental disorders. Dementia would be second, followed by depression, OCD, bipolar disorder and alcohol use disorder. 

Does mental illness get worse with age?

Mental illness may get worse with age. According to MDedge, “Personality disorders may appear to worsen with advancing age, although the prevalence remains stable with about 10%–20% of people age 65 or older having a personality disorder, Erlene Rosowsky, Psy. … Certain types of disorders are especially susceptible to worsening in response to specific stressors.”


Fruzzetti, A.W. (2017, Oct.) Why Borderline Personality Disorder is Misdiagnosed. Retrieved from nami.org.

Onlinepsychologydegree.info: “15 Scariest Mental Disorders of All Time”

Dontchangemuch.ca: “Mental Illness”

Mayoclinic.org: “Personality disorders”

Mayoclinic.org: “Mental illness”

Nimh.nih.gov: “Borderline Personality Disorder”

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