Dr. Ian Anderson, professor at the division of neuroscience and experimental psychology at the U.K.-based University of Manchester, was not involved in the study. However, he told Newsweek the findings are potentially important for casting light on an area of medicine that is not usually considered.
Further research is needed to unpack whether those who reported symptoms of depression were diagnosed with clinical depression; whether the medication or the participant's depression came first; and whether or not a drug having an association with depression in its side effects is to some extent arbitrary.
"Those on drugs associated with depression could have had more conditions that themselves are associated with depression," Anderson argued. An analysis of those only on drugs associated with depression and those without the association would also make the results clearer.
As for those concerned their medication could be causing depression, Anderson said the study shouldn’t lead anyone to stop medicating, as this always needs to be discussed with a doctor.
Anderson suggested that anyone whose mood has persistently worsened, especially inexplicably, after starting one or more medications should discuss this with a doctor. It may be possible to try an alternative treatment.
"The interactions between multiple medications is extremely difficult to predict, so it's also worth asking whether all the medications being taken are needed, as far as simplifying medication regimes where possible," he said.