He may be (I noticed 'talked to himself' as something folks noticed about him). OTOH, I think of folks like Dahmer, and they are shy and keep to themselves a lot apparently because they know their interests and others' just don't mesh. They know they are quite different than most people, and it's not a psychotic disorder at all. It may be something vaguely linked to OCD/compulsion disorders at some future time, I think, but it's not psychotic.
There are serial killers who definitely had the more psychotic symptoms, though, so I do agree with you, too
Jeffrey Dahmer had consistent bizarre obsessions and delusions which are positive symptoms of schizophrenia. He exhibited most of the negative symptoms of schizophrenia. (Not all schizophrenics have positive symptoms and negative symptoms.) He might not have been treated for schizophrenia, but he suffered with the disorder.
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Positive symptoms
In schizophrenia, positive symptoms reflect an excess or distortion of normal functions. These active, abnormal symptoms may include:
Delusions. These beliefs are not based in reality and usually involve misinterpretation of perception or experience. They are the most common of schizophrenic symptoms.
Hallucinations. These usually involve seeing or hearing things that don't exist, although hallucinations can be in any of the senses. Hearing voices is the most common hallucination among people with schizophrenia.
Thought disorder. Difficulty speaking and organizing thoughts may result in stopping speech midsentence or putting together meaningless words, sometimes known as word salad.
Disorganized behavior. This may show in a number of ways, ranging from childlike silliness to unpredictable agitation.
Negative symptoms
Negative symptoms refer to a diminishment or absence of characteristics of normal function.
They may appear with or without positive symptoms. They include:
Loss of interest in everyday activities
Appearing to lack emotion
Reduced ability to plan or carry out activities
Neglect of personal hygiene
Social withdrawal
Loss of motivation
http://www.mayoclinic.com/health/schizophrenia/DS00196/DSECTION=symptoms
Pensfan
verified psychiatric mental health nurse