I hope my writing is never affected me so much that it effects my writing, that's at what at some level editors are for, when the creative process has to worry about the nuts and bolts the creative process suffers.
Also, that is what rewrites are for. Write all your ideas out first, then rewrite.
"Ernest Hemingway once confided to George Plimpton during an interview that he rewrote the ending to "A Farewell to Arms" 39 times before he was satisfied. Why so many rewrites? Plimpton asked. Because, Hemingway responded, he wanted to get the words right."
A drug can affect a person, but it's sales will have an effect on the economy. Effect means--result, or to bring about (according to Strunk and White) You can replace the word effect with others such as --produce, bring about, result in etc.