Marijuana's impact on the human brain is complex and poorly understood, as it affects everyone differently and research is limited. In a new study, researchers attempt to clear up misinformation about the perils of weed by examining how marijuana use increases the risk of mental health or substance abuse disorders.

Led by Dr. Mark Olfson of the Columbia University Medical Center/New York State Psychiatric Institute in New York, the researchers reviewed data on some 34,653 United States adults who had been involved in the National Epidemiologic Survey on Alcohol and Related Conditions. They found a link between using marijuana and an increased risk of developing alcohol or drug abuse problems after a three-year follow up. This is backed up by information from the National Institute on Drug Abuse, which states that it’s possible that early cannabis use can tamper with dopamine levels later on in life, contributing to higher vulnerability to try other drugs. However, the NIH notes, “most people who use marijuana do not go on to use other, ‘harder’ substances.”

Interestingly, however, the researchers didn’t find the same association for marijuana use and an increased risk for mood or anxiety disorders.

For anyone who’s dabbled in weed, getting high can mean a variety of things — from reducing anxiety to exacerbating panic; and from curing migraines to causing psychotic episodes. Limited research into the health benefits of marijuana has found that cannabis may alleviate women’s period pain, treat seizures, and assist chemotherapy patients. Understanding how different types of cannabis can impact the health of unique individuals is still a complex and misunderstood arena, mainly because researchers find it difficult to access the drug.

But when it comes to how marijuana affects the brain and mental health, the lines get even more blurry. For a long time, doctors and the public believed that weed impaired memory and brain development in adolescents; and indeed, some recent research still backs that up. Other recent studies, however, have found that chronic use of marijuana in teenage years doesn’t cause any mental or physical health problems, and teen use of the drug doesn’t decrease intelligence either.

While more research will be needed to see whether using marijuana has a long-term impact on anxiety or mood disorders — or any other type of mental health issue from depression to post-traumatic stress disorder — the researchers caution for people to be careful when using the drug if they have any sort of mental health issue, as it affects everyone differently. “These adverse psychiatric outcomes should be taken under careful consideration in clinical care and policy planning,” the authors write.

Source: Olfson M, et al. JAMA Psychiatry, 2016.