EffectLet's take this one on first. By and large, an effect (pronounced eh-FEKT) is a noun. It is something that results from something. "The drug had the desired effect." "The intervention caused no effect on his behavior."
This form is also used to describe one's belongings. "We stored the patient's personal effects in a bag."
Scientists use effect to describe a law of some kind such as the photovoltaic effect. There are other meanings as well but nearly all of them are used as nouns.
Sometimes effect is used a verb, but not often, at least not in health care. "The Director of Nursing is trying to effect a change in the way adverse reactions are reported." Clinically, though, effect isn't used much as a verb.
AffectBy and large, the word affect (pronounced uh-FEKT) is used as a verb. It is something that happens. "Rheumatic fever can affect the heart and cause lasting damage to the myocardium." "Those two Code Blues have affected the staff's ability to deal with other patients."
But another meaning of the word, one used as a noun, is highly pertinent to healthcare professionals: affect (pronounced AH-fekt). This noun refers a patient's mien, countenance, or emotional presentation. "The mother exhibited a flat affect as she explained how her son was burned." "Expect to see a flat or blunted affect when dealing with a patient with schizophrenia."
So, aside from describing a person's demeanor, figure using effect when you need a noun and affect when you need a verb. Hope that helps.