Although there are many similarities between bipolar and schizophrenia, one isn't seen to lead to the other.
However, because psychiatric diagnoses have no physical test and are largely observation and guesswork, a person initially diagnosed with bipolar may later go on to develop schizophrenic symptoms, at which their diagnosis might be changed to "schizoaffective disorder", which combines symptoms of bipolar and schizophrenia.
It is also possible a person with schizophrenia could be initially misdiagnosed as bipolar.
If you want a solid answer straight out of the manual, stop there. The rest becomes speculative and different professionals will give you different opinions.
Now getting speculative, and into personal opinion: Yes, I think someone can have both schizophrenia and bipolar. Schizoaffective disorder still requires some link between schizophrenic symptoms and affective [mood] symptoms. It also requires that a person does not completely fulfil the criteria for schizophrenia. If a person fulfils BOTH the criteria for schizophrenia and for bipolar, but the two disorders appear superimposed rather than linked, I would say this suggests a dual diagnosis of bipolar + schizophrenia.
However, because psychiatric diagnoses have no physical test and are largely observation and guesswork, a person initially diagnosed with bipolar may later go on to develop schizophrenic symptoms, at which their diagnosis might be changed to "schizoaffective disorder", which combines symptoms of bipolar and schizophrenia.
It is also possible a person with schizophrenia could be initially misdiagnosed as bipolar.
If you want a solid answer straight out of the manual, stop there. The rest becomes speculative and different professionals will give you different opinions.
Now getting speculative, and into personal opinion: Yes, I think someone can have both schizophrenia and bipolar. Schizoaffective disorder still requires some link between schizophrenic symptoms and affective [mood] symptoms. It also requires that a person does not completely fulfil the criteria for schizophrenia. If a person fulfils BOTH the criteria for schizophrenia and for bipolar, but the two disorders appear superimposed rather than linked, I would say this suggests a dual diagnosis of bipolar + schizophrenia.