The studies conducted by Jick et al1 in the Canadian Saskatchewan Health database and the United Kingdom General Practice Research database did not find an increase in the relative risk of depression, psychotic symptoms, suicide, and attempted suicide in individuals prescribed isotretinoin compared with those prescribed antibiotics for acne. However, aside from noting that their sample size was too small to "generate stable estimates for suicide and attempted suicide," the investigators did not mention several methodological problems that limited their ability to draw the conclusion of no increase in risk. These include underascertainment of psychiatric disorders (apparently only diagnosis codes and not psychoactive drug prescriptions or interviews were used to define cases); underascertainment of suicides (death certificate data were not included as a source of information); and lack of data on acne severity and dose and duration of isotretinoin treatment. Also, because there was no control group without acne, a result of no difference in rates of depression between the groups might be due to an effect of acne.
Wysowski DK, Beitz J. Methodological Limitations of the Study "Isotretinoin Use and Risk of Depression, Psychotic Symptoms, Suicide, and Attempted Suicide". Arch Dermatol. 2001;137(8):1102. doi: