Events do not disturb people - their judgments about them do.
This is the core message of the first self-help manual, the Enchiridion - a collection of practical precepts from second-century Greek-speaking philosopher Epictetus.
The message is still as relevant today as it was 2,000 years ago.
American psychologist Albert Ellis (1913-2007) based his own form of psychotherapy, called rational emotive behaviour therapy, on Epictetus' insight that it is our emotional responses to events, rather than the events themselves, that make us anxious and depressed.
Psychotherapy is the treatment of mental or emotional problems by psychological means.
Dr Ellis declared: "Much of what we call emotion is nothing more or less than a certain kind - a biased, prejudiced or strongly evaluative kind - of thought.
"What we call feelings almost always has a pronounced evaluating or appraisal element."?
What did he mean by that?
Well, imagine that something bad happens to you: You mess up a job interview, or you get sick on the very day that you have tickets to see your favourite band.
Of course, you will feel bad. That is only natural. But exactly how bad you will feel is largely up to you.
You could say to yourself: I am disappointed about that interview. I really wanted that job.
Or, I am upset that I missed my chance to see that band.?
Such responses show perfectly healthy concern for your own happiness and well-being. You'll feel bad for a while, but you'll get over it.
On the other hand, you could say to yourself: I cannot believe I messed up that interview! I am such an idiot!
Or, missing that concert is just
my luck! I will never get the chance to see that band again. It is so unfair!?
Such thoughts are unhealthy and lead to unhealthy feelings. The more you brood over them, the worse you will feel.
Healthy thoughts are direct responses to the events themselves.
Unhealthy thoughts are focused on your own perceived inadequacy and ill-luck, or the unfairness of life.
WHEN BAD THINGS HAPPEN
The world is such that bad things sometimes happen. You want things, but do not get them. You care about people, but they get sick or die. You crave love and respect from people who cannot or will not give them to you. You try hard to succeed at something, but fail.
Dr Ellis argued that it is only right and proper to feel concerned and disappointed about such things. But you have to accept that they do happen.
Emotional problems arise when you insist - quite irrationally - that you must have the things you want; that the people you care about must not suffer; that you ought always to get the love and respect you crave; and that you must succeed whenever you try hard at something.
In his book, How To Stubbornly Refuse To Make Yourself Miserable About Anything, Dr Ellis wrote: "Assume that most times when you feel anxious, depressed or angry, you are not only strongly desiring but also commanding that something go well and that you get what you want."?
I have a friend who once experienced a bereavement in difficult and upsetting circumstances.
After her husband died, she went into a depression that lasted for many years. I remember her saying to me: "There is nothing left for me now. He is gone, and nothing can bring him back."
The bereavement was, of course, deeply upsetting.
However, both Epictetus and Dr Ellis would argue that depression was not the inevitable result. After all, lots of people experience difficult bereavements without spiralling into depression.
No, the depression arose because of her steadfast insistence that her husband ought not to have died; that she should not have to live without him; and that everything was therefore unremittingly awful.
Very often, prolonged negative feelings arise not so much because of what does happen, but because we torment ourselves needlessly with thoughts of what should, ought to and must happen.
•Gary Hayden is a philosophy and science writer.