Because dissociative identity disorder is exceptionally complex, the actual symptoms that each person with DID experiences can vary widely in both frequency and intensity.
The most common symptoms include notable gaps in memory that cause people to forget large portions of their lives during their youth. People with DID also often struggle with short-term memory issues, such as recalling how to perform everyday tasks or remembering what they ate for dinner. They may also experience short periods of complete amnesia during which they spend money, interact with people or behave in ways that are completely inconsistent with their personalities.
People who have DID also have more than one identity, which may or may not be obvious to others. Those with the possession form of DID have distinctly different personalities (previously called multiple personalities) that present in unique ways to friends and family members. By contrast, those with the nonpossession form of DID also experience different identities; however, they internalize these experiences — they often feel like they are detached from certain situations, emotions or behaviors.
Other common symptoms of DID include experiencing debilitating headaches, feeling depressed and anxious, and engaging in self-harming behaviors, including cutting and abusing drugs and alcohol. Some people with dissociative identity disorder may also hear the voices of their other identities, experience auditory and visual hallucinations, and feel like someone else is trying to take over their body.
It’s common for DID to be confused with schizophrenia; however, a distinct difference between the two conditions is that people with schizophrenia perceive the feelings, experiences, and voices as being external, while with dissociative identity disorder, the source of the symptoms is distinctly internal.