Here is an excellent Dalai Lama Quote of the Week from Snow Lion Publications.
Over the last few days I have been meeting scientists, mainly specialists on the brain, as well as psychologists and psychotherapists.... The majority of them agreed...that the key cause of the mental unrest and depression so prevalent today...is lack of sympathy and affection.
I think you might find the following story quite interesting. A few weeks ago I met someone whose mind, I was told, is severely disturbed. At the beginning, I used all of my reasoning to encourage him, explaining that, as a human being, there was no need for him to be discouraged, because we have such a good human brain and intelligence. I pointed out how, with determination, we can solve all our human problems and overcome all obstacles, and so there is no reason to worry or be discouraged or depressed. Personally, I always find this kind of reasoning is quite effective, but this time it failed. He was not impressed by this line of thinking. On the contrary, instead of showing any appreciation, he developed a rather contrary attitude. After listening to what I had to say, he became even more agitated, and asked me, "Why are you concerned about my problem? How do I know if your attitude is sincere or not?" I felt really sad. I was quite moved as well, and as I was explaining something or other, my hand reached out and caressed his arm. It was a natural gesture, a sincere expression of how I felt. Gradually, his mood altered; I could see his face beginning to change, and finally a smile began to appear. Then as I gained confidence, I increased that expression of affection. At last a big smile spread right across his face.
I told him, "Please consider me as an old friend. Any time, you can come to see me. Whatever I can do to help you, I am ready to do. I am at your service." When I said this, then his mood, it was clear, became very happy and joyful. The following day he came to see me again. When he arrived, he already had a happy air about him, but nevertheless he was trying to pretend otherwise and was not smiling. Anyway, what this incident really gave me was another confirmation of how powerful genuine compassion, love, or altruism can be, to affect other people's minds. And how they can remove fear and suspicion, and alleviate feelings of insecurity and mistrust.
So I always consider compassion as the key, not only for achieving and maintaining our own mental calmness, stability and happiness, but also as something extraordinarily useful for creating a healthy human society. By that I mean a happier and less harmful human society. Therefore--whether it be in individual cases, on a family level, a national level, or an international level--altruism, love and compassion are the basis for success, for happiness, and for a happy environment.
~ From Dzogchen: The Heart Essence of the Great Perfection by the Dalai Lama, translated by Thupten Jinpa and Richard Barron, Foreword by Sogyal Rinpoche, edited by Patrick Gaffney, published by Snow Lion Publications.