651. Depression is often referred to as the product of thought. Imagination causes issues that didn't exist.

652. Being happy around people makes you happier.

653. Convincing yourself that you slept well tricks your brain into believing you did.

654. The sort of music you listen to influences the way you view the world.

655. Romantic desire is biochemically indistinguishable from serious obsessive-compulsive disorder.

656. Phobias may be memories which are passed down through many ancestors by means of our DNA, according to new studies.

657. Researchers are thinking of adding Internet addiction to the general list of psychiatric illnesses.

658. The brain experiences rejection as physical discomfort.

659. We might persuade ourselves that a dull job was enjoyable if we weren't rewarded.

660. Sugar and fat were pretty good stuff to our predecessors.