Dissociative Identity Disorder (DID) is frequently misdiagnosed as schizophrenia. One reason for this is that some mental health professionals continue to refuse to accept that DID is a real condition despite the couple hundred years of documented cases and the significant and growing body of research that confirms it is a real condition. Because they don’t believe DID is real, they therefore never consider it as a diagnosis, leaving schizophrenia as a likely diagnosis instead.
Why This Happens
To see why DID may be misdiagnosed as schizophrenia, we need to look at the DSM-5-TR, the official book of diagnostic criteria for mental health in the United States. A diagnosis of schizophrenia requires that at least 2 of three possible symptoms be present. These symptoms are delusions, hallucinations, and disorganized speech. There are additional requirements for a diagnosis, but the presence of two of those three symptoms (delusions, hallucinations, and disorganized speech) are foundational requirements.
Delusions
Let’s start with delusions, often a key feature of schizophrenia. Delusions, as defined, are beliefs which are untrue and which cannot be changed despite proof to the contrary. To give an example, if it is a clear, sunny day and a person is adamant that it is raining even after going outside and being in the sun, then this person is said to have a delusion.
Thought Withdrawal Delusions
One example of delusions provided in the DSM-5-TR is a kind called “thought withdrawal,” where people believe that their thoughts have been removed by an outside force. Now, there is a phenomena in DID often called “thought snatching,” where one part’s thoughts vanish, taken away by another part.
If you were paying close attention, you might notice that, unlike with schizophrenia, where a person is claiming thoughts are controlled from the outside, a person with DID, would attribute this to another internal part (if they were aware that other parts could do this, that is). A mental health professional who is hurrying to make a diagnosis could easily hear this as a symptom for schizophrenia even though it is specifically addressed in the section about DID in the DSM-5-TR.
Delusions of Control
Another type of delusion is called delusions of control and involves the belief that one’s body or actions are being acted on or manipulated by some outside force. In DID, a common phenomena is for a fronting part, often the host, to say that they don’t feel like they are in control of their actions or speech. They will report that they tried unsuccessfully to intervene and stop actions or speech with no success. However, I’ve never heard any claim it was due to some outside force; instead, they understood that they were not the part “in the driver’s seat” at that moment. They were co-conscious to some extent but were not in control of the body. That’s very different from a schizophrenic person’s experience but, again, a careless or hurried mental health professional might miss this distinction.
Persecutory Delusions
A third type of delusion which can easily be confounded with events in DID is the persecutory delusion. People with this delusion believe that they are going to be harmed, or harassed by individuals or organizations. Again, these are outside forces the schizophrenic person believes will be acting on them, even without any evidence. Contrast that to a person with DID who has young parts who experienced profound abuse and who may be fronting but unaware that years have passed since their abuse. They are stuck back in the trauma. It’s easy to see how they could be terrified of being hurt and how someone who did not understand this is DID could attribute this to a delusion. Or it could be that the person with DID is experiencing a flashback, reliving a past trauma in the present moment. This, too, could be viewed as a delusion since the person is clearly not being abused in the present moment.
Hallucinations
Hallucinations are another of the three symptoms, of which two must be present for a diagnosis of schizophrenia. The DSM-5-TR describes hallucinations as “perception-like experiences that occur without an external stimulus. They are vivid and clear, with the full force and impact of normal perceptions and not under voluntary control.” Hallucinations can be experienced in any sensory modality but are most commonly auditory in nature, followed by visual. Auditory hallucinations often occur as voices, which may be known voices or voices that are unfamiliar. This is a key statement in the DSM-5-TR section on schizophrenia: these voices “are perceived as distinct from the individual’s own thoughts.” I bet you can see how this is problematic when it comes to DID!
Hearing voices is extremely common in DID. In fact, it’s more common in DID than in schizophrenia. Of course, I wouldn’t call it a delusion in DID because these voices are real and people can communicate with the voices in their systems. People with DID may also see things which they can understand cannot be there but which they see. People aren’t as familiar with visual “hallucinations” and might immediately think of schizophrenia despite the fact that the person with DID knows that what they aren’t seeing isn’t really there. (In this case, it’s more of a flashback than a hallucination).
But imagine a person who has DID and has been admitted into an inpatient program. The psychiatrist probably spends all of 15 minutes with this person. The person shares that she hears voices in her head but that they aren’t her thoughts. If she shares that the voices are telling her to kill herself, the psychiatrist will likely call this a command hallucination without considering DID. The psychiatrist can easily believe he or she has found the required two symptoms for a diagnosis of schizophrenia.
Catatonia
Another symptom that can be present in schizophrenia (but is not required) is that of catatonia. Catatonia can present in different ways and the one that is most familiar is probably that of a person who is unmoving, perhaps in a contorted position, and unresponsive to anything going on around them. Catatonia can also be present as “a marked decrease in reactivity to the environment” and can include “a complete lack of verbal and motor responses.” If you are familiar with polyvagal theory at all, you might realize right away that something else would appear like this: hypoarousal. Hypoarousal is one of the nervous system’s defenses, like fight and flight. In hypoarousal, the person is basically overwhelmed and checked out, not really aware of what is happening around them. This state wouldn’t just happen; it would need a trigger. But in that inpatient setting with the hurried assessment, it’s possible the doctor wouldn’t notice that a particular question or topic preceded the shut-down. If they don’t, all they see if that the person is no longer responding, or barely responding, and may attribute it to catatonia and to schizophrenia.
Hostility and Aggression
The DSM-5-TR also notes that “hostility and aggression can be associated with schizophrenia.” I have yet to meet a system which doesn’t have an angry, hostile, or aggressive part (for good reason). Imagine, that system finding themselves in the noisy, busy inpatient setting, scared and not knowing what is going on. It’s possible that a fearful part could front, but I think it’s more likely that a protective and angry, aggressive, or hostile part might front. A careless or busy clinician could easily chalk this up to schizophrenia.
Overlap in the Conditions
Research has been done on this topic, comparing diagnoses of what they called schizophrenic spectrum disorders (this includes some of the schizophrenic-”lite” diagnoses) and dissociative disorders (not just DID), and while some studies found no instances of people being diagnosed with both, other studies found that between 9% and 50% of schizophrenic spectrum patients also met the criteria for dissociative disorders. One study showed that in a sample of patients diagnosed with DID, 74.3% also met diagnostic criteria for a schizophrenic spectrum disorder, 49.5% met the diagnostic criteria for schizoaffective disorder, and 18.7% met the criteria for schizophrenia. To my mind, anyone diagnosed with schizophrenia or one of the schizophrenic spectrum disorders would be well advised to be assessed for DID by someone who is an expert in DID.
A Major Oversight of the DSM-5-TR
Here’s where I think the DSM-5-TR messes up: in what are called “differential diagnoses.” For each condition listed in the book, there is a section which lists other conditions which must be ruled out. It seems obvious to me that DID should be one of those conditions which must be ruled out before making a diagnosis of schizophrenia. But, unbelievably, DID is not one of the conditions that are listed to be ruled out. If you look at DID, however, you will find schizophrenia as one of the differential diagnoses to be ruled out prior to diagnosis. Explain the sense to me, that one must be ruled out in one direction but not the other. Truthfully, I think even if DID was a differential diagnosis to be ruled out for schizophrenia, it likely wouldn’t make much difference unless the clinician was taking time and care to explore the root of the symptoms that could belong to either schizophrenia or DID. But without DID being one of the issues on the list to be ruled out, it might not occur to some clinicians and so doesn’t happen.
The Importance of Context
One underlying thread through this is context. Context is what determines how the symptom should be interpreted. Going back to my example of the fronting part of a DID system reporting that they have no control over the body. Without looking into this symptom more carefully, it might be missed that the alter is not claiming someone outside the body is controlling her body. Context is overlooked when the clinician doesn’t have adequate time to spend with the person before making a diagnosis. And context is overlooked if the diagnosing clinician simply refuses to entertain the possibility of DID as a diagnosis.