本人认为 for dealing with drug users 是作状语的。做定语的话，这句话的意思是：一些学校已经引进了更加严格的处理吸毒者的规则。for 就是多余的了，用现在分词 dealing with 就可以做后置定语了。所以这句话应该是想表达： 一些学校已经引进了更加严格的规定来处理吸毒者。（注意两个句子翻译的区别）

rules for dealing with drug users：从结构和搭配看，for dealing with drug users 作定语，修饰rules。

for 的意思很明显，表示“rules 的目的”。

rule 后面接不定式作定语，应该是不存在的。因为rule 自身不能deal with drug users，它只能是人的“工具”。

我再举个类似的例子，动名词作定语时的转换，即可说明它们的修饰关系：

cooking rules：动名词作定语， 等于rules for cooking。这足以说明for cooking 作定语。

我用足够的例子证明我的观点：

动名词作定语，说明动名词和被修饰语是“目的或用途的关系”。所以，我们可以用for doing，used for doing，或者which is used for doing来置换这个动名词，放在被修饰语之后作定语。例如：

a swimming pool

①→ a pool for swimming

②→ a pool used for swimming

③→ a pool which is used for swimming

限于篇幅，以下词组仅用第①种情况转换：

a walking stick → a stick for walking

a sleeping car → a car for sleeping

a waiting room → a room for waiting

a swimming pool → a pool for swimming

a washing machine → a machine for washing clothes

a writing desk → a desk for writing

a reading room→ a room for reading

a bathing cap→ a cap for bathing

a changing room→ a room for changing clothes

a sitting room→ a room for sitting

a watering can→ a can for watering flowers

a guessing game→ a game for guessing words

an ironing board→ a board for ironing clothes

a collecting tin→ a tin for collecting money

a hiding place→ a place for hiding

a racing bicycle→ a bicucle for racing

an operating table→ a table for operating

building materials → materials for building

a diving board→ a board for diving

reading materials → materials for reading

a closing speech→ a speech for closing a meeting

working hours→ hours (time) for working

a smoking room→ a room for smoking

a dancing hall → a hall for dancing

a washing machine → a machine for washing clothes