Cannabis increases manic and depressive symptoms, according to a recent study.

Around 2 percent of the UK population has Bipolar Disorder, with up to 60 percent using cannabis at some point in their lives, but research in this area is limited and reasons for high levels of use are unclear.

"One theory that is used to explain high levels of drug use is that people use cannabis to self-medicate their symptoms of bipolar disorder," researcher Dr. Elizabeth Tyler said in a statement.

The study looked at people diagnosed with bipolar disorder but who were not experiencing a depressive or manic episode during the six days the research was carried out.

For the study, each participant completed a paper diary about their emotional state and drug use at several random points daily over a period of week. This enabled people to log their daily experiences in the moment before they forgot how they were feeling.

The study found that the odds of using cannabis increased when individuals were in a good mood. Cannabis use was also associated with an increase in positive mood, manic symptoms and paradoxically an increase in depressive symptoms, but not in the same individuals.

"The findings suggest that cannabis is not being used to self-medicate small changes in symptoms within the context of daily life. However, cannabis use itself may be associated with both positive and negative emotional states. We need to find out whether these relationships play out in the longer term as this may have an impact on a person's course of bipolar disorder," Tyler said.

The findings are detailed in PLOS One.