21st Dec 2022
Borderline schizophrenia is one of a range of severe mental disorders that more than 11 million Americans experience in any year.  There has been much debate within the clinical community about whether or not borderline schizophrenia is a separate diagnosis to schizophrenia or borderline personality disorder, and it currently isn’t recognised in the latest diagnostic statistical manual, the DSM-V, as its own condition. However, what is most important is that you get the right support if you are experiencing any of the symptoms previously categorized under this diagnosis. Borderline schizophrenia can develop at any point in someone’s life but symptoms usually appear between teenage years and someone’s mid-20s, which can be a really important window of opportunity for getting treatment early and preventing the illness from developing.  It is a long-term mental health disorder that particularly impacts someone’s perception of reality and the way that they think, feel, behave and process information. Even when this diagnosis was separate to borderline personality disorder and schizophrenia, in the DSM-III, some clinicians questioned this because of the crossover in symptoms.  Borderline schizophrenia is sometimes called schizotypal personality disorder (SPD), because it was understood as being part of a spectrum of schizophrenia. However, the term is generally seen as outdated now and not used very often, particularly because of the stigma that can accompany a diagnosis of any personality disorder, which implies someone’s mental health problem is inherent to who they are.   There is no way of predicting who will and won’t develop borderline schizophrenia symptoms, however, adoptive, family, and twin studies show that symptoms are often found among the relatives of people with this diagnosis or similar diagnoses. 
There is significant crossover between borderline schizophrenia and other diagnoses, so a helpful way to understand it is through its component symptoms, which are now categorized under borderline personality disorder and schizophrenia.
Schizophrenia is a relatively uncommon, severe mental health problem in which people often become disconnected from the world around them and their perception of reality becomes warped.
Borderline personality disorder (BPD) is a mental illness characterized by an intense fear of abandonment, problems with self-image, and impulsive behavior.
To simplify the impact of these diagnoses, people with schizophrenia often struggle with their relationship with the world and reality, and people with BPD often struggle with their relationship with themselves and other people. People with borderline schizophrenia will struggle with both things to varying degrees.
There are also some differences in specific symptoms - compared to patients with schizophrenia, patients with BPD tend to have fewer delusions (beliefs that aren’t grounded in reality), social withdrawal and disordered thoughts. 
People with schizophrenia are also more likely to experience the symptoms of psychosis, which include hallucinations (particularly hearing voices), and paranoia. The combination of symptoms in borderline schizophrenia varies from person to person but generally they have more in common with individuals with schizophrenia compared to people with BPD.
Borderline Personality Disorder (BPD) is a severe mental health problem in which people often have a strong fear of abandonment, struggle with self-image, and are likely to take part in impulsive behavior. People with this diagnosis often view the world and people in a very black and white way.
A common symptom of BPD is mood swings, because people with this diagnosis often struggle to manage their feelings. This can have a significant impact on their relationships with others and the way they perceive themselves. 
BPD was first recognised as a diagnosis in the DSM-III, which was also when borderline schizophrenia appeared as a separate diagnosis. 
What adds to the complexity of BPD is that people with this diagnosis often have other mental health problems, including PTSD, bipolar disorder and depression. Because of the relationship between BPD and impulsive behaviors or risk taking, people with this diagnosis might also struggle with substance abuse.
Other common symptoms of BPD include:
Generally, crossover in symptoms with schizophrenia is a sign that someone has severe BPD and therefore may require more intense care. Hearing voices, also known as auditory verbal hallucinations (AVH), are the most common symptom experienced by people with BPD and schizophrenia, and therefore also borderline schizophrenia.  Around 71 percent of people with schizophrenia hear voices, while 40 percent of people with BPD do. 
Schizophrenia is a relatively uncommon, severe and chronic mental health problem in which people often become disconnected from the world around them and their perception of reality becomes warped.
Schizophrenia is experienced in episodes, so rather than someone experiencing symptoms at a steady level of severity, there are times when it appears to be in remission. This is why it is so important if you know someone with this diagnosis, that you are aware of the signs of schizophrenia, as this might mean they are about to experience an episode and need care. Schizophrenia does not mean someone has a ‘split personality’, as is commonly misunderstood.
The DSM-5 removed previously accepted subtypes of schizophrenia, which grouped symptoms under different names including paranoid schizophrenia, catatonic schizophrenia, and residual schizophrenia. This was largely due to disagreement among clinicians about these sub-types and overlaps in symptoms. 
According to the DSM-5, in order to qualify for a schizophrenia diagnosis, you need to have experienced at least two of these symptoms for at least a month:
As well as these symptoms, the manual states that you need to show that you are not functioning at your usual level in relation to your work, close relationships, or self-care. 
While borderline schizophrenia was previously recognised as a diagnosis, for many years the same symptoms have been understood to be part of either borderline personality disorder or schizophrenia.
In the latest manual, the DSM-5, psychotic symptoms, like hallucinations and paranoia, are not listed as being part of BPD but are categorized as a common part of schizophrenia.
There is also still some debate about whether schizophrenia should still be understood as multiple diagnoses because its symptoms vary so much from person to person. The frequency of people’s episodes of strong symptoms can also vary significantly.
Changes to the most recent edition of the DSM state that someone now needs to experience at least two of the following symptoms to qualify for a schizophrenia diagnosis.
Symptoms can be grouped as follows:
This group of symptoms are things that people with schizophrenia experience that others don’t – the use of the word 'positive means’ they are in addition to most people’s reality.
People with schizophrenia often have sensory experiences that others around them are not experiencing.
This might mean seeing things that aren’t there, or a distortion of what others can see, like insects crawling up a wall because of the way light is moving on it. It could mean hearing things, like voices telling the person to do things or that they are worthless.
Hallucinations can involve any of the five senses. Visual hallucinations are also relatively common for people with borderline personality disorder, and therefore were categorized as part of borderline schizophrenia.
People with schizophrenia might believe things that are untrue, or are overly exaggerated. For example, a delusion might be that someone believes they are able to fly or are invisible. It might also look like paranoia, for example a delusion that they are being watched by everyone.
These symptoms are less common among people with BPD, although the biggest overlap is with paranoid beliefs, which was categorized as part of borderline schizophrenia. When people with BPD do experience these symptoms it is often in correlation to their likelihood of needing to be hospitalised and their risk of suicide.
This group of symptoms relate to someone’s social functioning and engagement with the world being limited or impaired.
A common negative symptom is to become extremely withdrawn, avoiding people altogether and retreating into your own world. Another is to lose motivation or interest in the things you would usually find enjoyable.
People with BPD are less likely to withdraw or have flattened emotions and are more likely to feel intense distress, fear or anger, although there is some crossover in levels of detachment.
To differentiate, people with schizophrenia are likely to feel detached from the world, while people with BPD are likely to feel detached and dissociate from themselves. Someone with borderline schizophrenia might experience both things.
These symptoms are to do with the way the person is processing things and behaving. A person experiencing cognitive symptoms might seem very disordered in their thinking, jumping from one topic to the next without any connection.
Cognitive symptoms also include unusual physical behavior, for example fidgeting a lot, and unusual behavioral traits like playing pranks on people or refusing to follow instructions.
These symptoms are more specific to schizophrenia, although people with BPD might be perceived to be partaking in unusual behavior if they do manipulative things to avoid abandonment. A helpful way to differentiate between diagnoses is through the motivation behind this behavior.
Most people with borderline personality disorder, schizophrenia or borderline schizophrenia will need a comprehensive treatment plan involving medication, talk therapy, lifestyle changes and the support of friends and family. Most people with these diagnoses will work with a psychiatrist, who will help them manage their medication and symptoms.
Certain kinds of talk therapy are often used to treat symptoms associated with these diagnoses, if someone is taking medication and therefore stable enough to engage in therapy.
Psychosocial therapy can help people to engage with the world and people around them, and to integrate into their community. This therapy might also be used as rehabilitation, for example, following a stay in hospital.
Family therapy is very effective, particularly for people with schizophrenia symptoms, as family members are often best placed to spot the signs the person is about to experience an episode, and encourage them to stick to their treatment plan.
Dialectical Behaviour Therapy (DBT) is also commonly prescribed for borderline personality disorder. It is a type of talk therapy that originated from the same school of thought as Cognitive Behaviour Therapy (CBT), and focuses on self-acceptance and learning to regulate your feelings.
The use of ‘dialectical’ means this therapy aims to help someone to bring together two things that seem opposite - that they can accept who they are and how they behave, while also trying to achieve change.
The Food and Drug Administration hasn’t approved any medications to date for the specific treatment of BPD. However, medical professionals can prescribe several drugs to help manage particular symptoms or to treat co-existing mental health problems, including antidepressants, mood stabilizers and sleeping pills.
If someone also has schizophrenia, or borderline schizophrenia, they are most likely to be prescribed antipsychotics, which are powerful medicines that often produce side effects such as weight gain, heart disease or diabetes.
Older antipsychotic medicines that are still prescribed include (brand names in brackets):
Newer medicines include:
People will often have to take more than one medication to manage their symptoms, so it is important to manage the different dosages and their interaction effects with your doctor.
People with schizophrenia, borderline schizophrenia or borderline personality disorder might also be assigned a support worker who helps them with practical, everyday tasks, like keeping their house clean and tidy, grocery shopping, looking after themselves and attending appointments.
If you are close to someone experiencing borderline schizophrenia symptoms, your support can be one of the most effective types of treatment options. People with these symptoms often lack awareness about their illness, so it is important for friends and family to stay alert to the signs that they might be becoming more unwell.
Because of this lack of awareness, along with struggling with self-care, people experiencing these symptoms are also statistically likely to struggle to stick to their treatment plan, particularly in relation to taking medication. Again, the role of friends and family in helping them to do this is crucial. 
As it is common for people with borderline schizophrenia and similar diagnoses to relapse and experience severe episodes, it is important to develop a crisis plan with them for if this happens. This should include calling 911 if the person poses a threat to themselves or anyone else.
It is also important to look after yourself if you are experiencing borderline schizophrenia symptoms. One of the most important elements of self-care is to recognise the signs that you are becoming more unwell. This might include struggling to concentrate on things or not looking after yourself like eating or washing enough.
Try to avoid things you know can trigger an episode if you can, like drugs or alcohol or arguments with friends and family. Instead, engage in things you enjoy and find relaxing, like playing or listening to music, or getting outside into nature.
If you hear voices, joining a support group with people who also experience this symptom can help to make it feel less overwhelming and help you to find ways to manage it.