Laz, part of me believe psychology to be a science, purely because of the way it is studied and applied. The other part of me believes that, as a subject, it stands alone but with a slight link to science.
If we look at actual sciences, they are made up of facts with possible theories based on those facts. Experiments are conducted to approve/disprove theories and/or assumptions related to facts and variables.
In psychology, some teachings are based on fact but some are mere assumptions. Theories are then derived from mere assumptions as opposed to facts. With psychology, there seems to be less emphasis on fact than with subjects that are actually considered to be sciences and I feel thats what sets psychology apart from other sciences, if you choose to call it a science. Like I say, part of me does whereas part of me doesn't.