When people think about someone hearing voices in their head, they usually think about schizophrenia or psychotic episodes. Interestingly, however, voices are actually more common in dissociative identity disorder (DID) than in schizophrenia. Voices may also be heard by people suffering from PTSD or other trauma-related disorders. As you can imagine, a good many people who have DID are often mistakenly diagnosed as having schizophrenia. It might surprise you to know that DID is not a rare disorder. The DSM-5, the psychiatric “Bible”, estimates that 1.5% of the population has DID and only 0.3 to 0.7% have schizophrenia. How does that compare to some diagnoses we think of as much more common? Well, both Bipolar disorders together are estimated to occur in 1.4% of the population. Have you heard of generalized anxiety disorder? The DSM-5 estimates that 2.9% of adults are estimated to have that in any 12-month period. So as you can see, there are some real reasons to make sure DID is considered as a possibility when voices are a symptom and schizophrenia is being considered.
Researchers have studied the phenomenon of hearing voices to see if they could identify differences in voices between people with schizophrenia and DID. They have found significant differences. One difference is in how the voices typically react in schizophrenia and DID when addressed. One similarity, however, is that both groups are more likely to hear the voices internally rather than as external voices.
Some research studies have found hearing voices in up to 85% of PTSD patients and in 90% or more of people with DID. To be fair, other studies have found rates of 5% and 30%, correspondingly. One research study noted that how they asked about the voices had a large impact on what the study subjects revealed, so my personal hunch is that the low numbers are under-reporting the prevalence of hearing voices in those populations. If you are being asked about voices in a research study and have the idea that this means something bad or scary about you, you’d probably be less likely to share it with researchers.
It’s important to realize that simply because a person hears voices, it does not mean they are “crazy,” are suffering from psychosis, or have schizophrenia. For example, it is not uncommon to hear the voice of a recently deceased loved one. That’s grief, a very normal condition. What I hope you take away from this is that hearing voices isn’t particularly uncommon and it doesn’t mean something dire. That said, if the voices are ongoing (rather than an instance here or there after someone has died), they are a likely indication of trauma in the person’s history. The good news is that we have effective ways to help people for whom the past trauma is still imposing on their present.
I work with clients with dissociative identity disorder. If you’ve worried that you might be going crazy or wondered if you have DID but didn’t know who to talk to about it, I invite you to contact me. One thing I tell my clients when they are learning about their DID is that it can make a person FEEL crazy but they aren’t actually crazy.