Yes, it is possible for a person to exhibit different personality traits or behaviors without having Dissociative Identity Disorder (DID) or schizophrenia. In fact, it is quite common for individuals to display various facets of their personality in different situations or with different people. This phenomenon is generally referred to as having different "personas" or "roles" rather than separate identities as seen in DID.
People often adjust their behavior based on the context they find themselves in. For instance, a person may act more formally and professionally at work, but more relaxed and casual around friends and family. These shifts in behavior can be influenced by cultural norms, social expectations, and personal preferences. This variability in behavior is considered normal and is a part of the complexity of human psychology.
However, it is important to distinguish between these normal variations in personality and the distinct identities seen in Dissociative Identity Disorder. In DID, a person experiences a disruption of identity characterized by two or more distinct personality states (formerly known as multiple personality disorder). These different identities can take control of the person's behavior and memory at different times, often without the person's awareness. This condition is much more severe and different from the typical variations in personality observed in the general population.
Similarly, schizophrenia involves a range of symptoms, including delusions, hallucinations, disorganized thinking, and altered perceptions of reality. It does not specifically involve the presence of multiple personalities.
In summary, experiencing different facets of one's personality in various contexts is normal and doesn't necessarily indicate a disorder. However, if someone feels their behavior or experiences are causing distress or impairment in their daily life, it is always advisable to seek professional help from a mental health expert for proper evaluation and support.