A 2007 studyTrusted Source published in the British Journal of Cancer examined hand preference and cancer risk. The study suggested that women with a dominant left hand have a higher risk of being diagnosed with breast cancer than women with a dominant right hand
A 2011 study from the American College of Chest Physicians suggested that left handers have significantly higher chances of developing periodic limb movement disorder (PLMD).
A 2013 Yale University study focused on the left and right handedness of outpatients in a community mental health facility.
When studying patients with psychotic disorders, such as schizophrenia and schizoaffective disorder, 40 percent of the patients reported writing with their left hand. This was much higher than what was found in the control group.
A 2007 studyTrusted Source published in the Journal of Traumatic Stress screened a small sample of nearly 600 people for post-traumatic stress disorder (PTSD).
The group of 51 people who met the criteria for a possible PTSD diagnosis contained significantly more left handers. Left-handed people also had significantly higher scores in arousal symptoms of PTSD.
A 2011 study published in The British Journal of Health Psychology indicated that left handers reported consuming more alcohol than right handers. This study of 27,000 self-reporting participants discovered that left-handed people tended to drink more often than right-handed people.
A 2014 Harvard study published in the Journal of Economic Perspectives suggested that left handers in comparison to right handers:
have more learning disabilities, such as dyslexia
have more behavior and emotional problems
complete less schooling
work in jobs that require less cognitive skill
have 10 to 12 percent lower annual earnings
A 2001 study of over 1.2 million people concluded that left handers did not have a health risk disadvantage for allergies and had lower rates of ulcers and arthritis.
According to a 2015 study, left-handed people recover from strokes and other brain related injuries faster than right-handed people.
A 2006 studyTrusted Source suggested that left hand dominant people are faster than right hand dominant people at processing multiple stimuli.
A 2017 study published in Biology Letters indicated that left hand dominant athletes in certain sports have a much higher representation than they do in the general population. For example, while about 10 percent of the general population is left hand dominant, about 30 percent of the elite pitchers in baseball are lefties