why is it difficult to determine a psychological disorder?

[Jones]

need help on my psychology homework!!

[curlz]

many psychological problems have similar symptoms.

for instance, most psychological problems have depression and/or insomnia as symptoms.

[Hawke]

because unlike physical injury or illness the patient rarely agrees that there is anything wrong with him, plus if a totally sane person was accused of being insane his reaction to being arrested and locked up might be interpreted as insanity as he would justifiably be angry

[hummingbird]

Because the person WITH the disorder doesn't always tell you all their symptoms, or forget some or purposely leave some out (for various reasons) making weeding through the different yet similar definitions difficult!

[Sandstorm]

There is never a set, concrete set of symptoms and when you're dealing with the mind, it often involves many complex layers.