为什么强迫症英文obesessive-compulsive disorder前俩单词一个意思？

Question

obsessive和compulsive一样的都是强迫的意思。为什么这样用呢？

Answer 1

obsessive和compulsive一样的都是强迫的意思, 但
obsessive 强迫主动 means think about sth too much
compulsive 强迫服从 means doing sth persistently and repetitively without it necessarily leading to an actual reward or pleasure.
简单点，一个乱想 一个瞎做。
So this way, a man with OCD will find his obsessions uncontrollable and the compulsions impossible to resist.

Hope you get it.

Answer 2

语言是不用问为什么的，比如这个词。背下来就好了。