[Psychiatric] drugs have so many side effects because using them to treat a complex psychiatric disorder is a bit like trying to change your engine oil by opening a can and pouring it all over the engine block. Some of it will dribble into the right place, but a lot of it will do more harm than good.

Source: "Your Brain is More Than a Bag of Chemicals." TEDxCaltech. Jan. 2013. Conference Presentation. Additional Information: This quote by neurobiologist David Anderson means that commonly prescribed psychiatric medications, such as antidepressants, are too heavy-handed an approach to treating mental illness: they produce some of the intended effects, but they also cause many unintended effects, such as unpleasant side effects. The quote is from Anderson's 2013 TED Talk about emerging research on brain functioning that could lead to more targeted psychiatric medications. Watch the full TED Talk here: David Anderson - Your Brain Is More Than a Bag of Chemicals