A 2013 review which specifically examined the effects of cannabis on the lung concluded "indings from a limited number of well-designed epidemiological studies do not suggest an increased risk for the development of either lung or upper airway cancer from light or moderate use, although evidence is mixed concerning possible carcinogenic risks of heavy, long-term use." The report also found “limited evidence” of links between marijuana use and several other negative outcomes, including an increased risk of testicular cancer, triggering a heart attack, chronic obstructive pulmonary disease, and other pregnancy complications. And it found “moderate” to “limited” evidence that marijuana use might worsen symptoms or risk for some mental health issues, including depressive disorders, bipolar disorder, suicidal ideation and suicide attempts among heavier users, and anxiety disorders, particularly social anxiety disorder among regular users.