There is no scientific prove that there is a relation between intelligence and mental illness but there is a possibility that there could be a link between intelligence and bipolar disorder.
Many creative thinkers are known to have been associated with mental conditions, some of them are; Vincent Van Gogh, Buzz Aldrin, Emily Dickinson, and Ernest Hemingway. Many believe that their mental condition gives these creative people an edge.
Everyone experiences feelings of sadness, or low mood, at times in their lives but when symptoms are present continuously for two weeks or more, a diagnosis of clinical depression may be made. This serious mood disorder affects how an individual sleeps, as well as his ability to eat and work. Which symptom is 'worst' depends on whether you are viewing this from the point of view of the sufferer or from that of the doctor.
Not all sufferers of clinical depression will experience all of the following symptoms but the feeling of utter hopelessness, that no event or effort on anyone's part will every change their peson's situation may well be the worst symptom in their eyes. The doctor is most likely to be worried by any suicidal thoughts.
Other symptoms may be irritability, feelings of guilt and worthlessness, low energy, fatigue, slowness of speech and movement, difficulty concentrating, sleeping (or over-sleeping), aches and pains without physical cause and loss of appetite. Family members may find their ability and lack of action the hardest aspects to bear as well as seeing their loved one constantly in a state of desperate sadness.