Investigators are trying to know the exact cause of Germanwings crash, but according to mental health experts, any mental illness that Germanwings co-pilot Andreas Lubitz had is the only possible reason of the tragedy. As per some scientific studies, most of the people who have mental health problems do not hurt other people.

Seena Fazel, a professor of forensic psychiatry at the University of Oxford in England, said factors like anger or drug and alcohol abuse are usually involved when people commit strange acts such as deliberately crashing a plane.

According to reports, while investigating at Lubitz's home, investigators discovered a note by a doctor that excused Lubitz from work on the day of crash. As per reports of The New York Times, there was another note that had been ripped up. Spiegel magazine of Germany reported that the investigators found some clues, which suggested that Lubitz had a mental health problem, though it has not been confirmed.

Fazel said, "Mental illnesses have been linked to a slightly increased risk of being convicted of a violent crime. But even if Lubitz had mental health problems, that doesn't necessarily explain why he apparently flew a plane full of people to their deaths".

According to a study conducted by Fazel, which included more than 47,000 people in Sweden, people with depression were three times more likely to commit an aggressive crime than people who are not depressed. But, the number of people with depression who commit crimes is still less. The study stated that just 3.7% of men and 0.5% women with depression commit such crimes, compared to 1.2% of men and 0.2% of women in the general population.

The study has been published in February in the medical journal The Lancet Psychiatry.