Regarding the normal personality dimensions of the two
groups, we are in agreement with Abdel-Gawad and
Osman23, that the amphetamine psychosis group has higher
scores regarding neuroticism and lie scales than the other
psychoses group. The other psychoses group has higher
scores regarding psychoticism scale than the amphetamine
psychosis group. The differential association of cluster B
dimensions with amphetamine psychosis (antisocial and
borderline) and of cluster A dimensions with the other
psychoses group (schizoid and schizotypal), are similar to
those of earlier studies48,52-60 and may partly be explained by
the similar neurobiology of these conditions61. For example,
increased dopaminergic function in schizotypal personality
disorder has been related to psychosis-like symptoms and
abnormalities in the serotonergic system have been found
in individuals with borderline personality disorder and
antisocial personality disorder. We found no significant
difference among the amphetamine psychosis group and
the other psychoses group regarding cluster C personality
disorders. So, our results could not confirm the previous
developments in this area of research40,58,59,62-64. However, to
date, the search for such etiological subtypes of schizophrenia
has not been fruitfu