Oftentimes, an individual will forge through the challenging steps of substance abuse treatment and victoriously overcome their addiction only to fall into relapse weeks or months later. Something keeps them from completely overcoming their addiction. Other disorders that had been masked by their addiction later surface and once again begin working against the individual's ability to fully heal-both mentally and physically. Many research articles have pointed to the connections between mental illness and substance abuse addiction. They interweave with one another and produce complexities that make it difficult for doctors to properly distinguish characteristics of addiction vs. mental disorders. For an individual to fully recover, they must be treated simultaneously for both their mental disorder and substance abuse addiction. The similar overlapping symptoms present a challenge to specialists as they try to find the end of relapse. Co-occurring Disorders Are Often the Reason For Relapse Specialists differ in how many addicts have co-occurring disorders that go unnoticed until after the person has recovered from their substance addiction. Some say as little as 20 percent while others say nearly 100 percent. An official study in 2011 by the Substance Abuse and Mental Health Services Administration (SAMHSA) revealed that 20 to 25 percent of individuals with mental illness were also engaged in substance abuse. Substance abuse masks the symptoms of other mental illnesses that may be the cause of the addiction or that may have developed as a result of the addiction. The mental disorders most commonly seen in individuals with substance abuse are Anxiety, Depression, Post-traumatic Stress Disorder (PTSD), Bipolar Disorder, and Schizophrenia. Working Against Each Other Researchers are still investigating the complex relationships between addiction and mental illness. Which has greater power over controlling the other? A person may fall into depression because they have an alcohol addiction. A person may fall into an alcohol addiction by trying to drink away their depression. Specialists not only have to distinguish between whether a patient's symptoms stem from an addiction or mental disorder, but must be aware of other complexities that muddy the plan of treatment. Substance abuse can cause changes in the brain that can cause mental disorders. Withdrawal symptoms from substance abuse may cause hallucinations that doctors may mistake as schizophrenia symptoms. Treating Both Disorders Simultaneously Doctors agree that, if possible, it is best to treat both disorders at the same time. Rather than rid the body of one villain, leaving the other one strong, both should be taken down simultaneously. The irony in helping someone with a dual diagnosis of drug addiction and a mental illness is that once clean of drugs, a person who has overcome drug abuse sometimes rejects taking any drugs at all-even ones that will help them with mental illness or common illnesses. For the best success, the clinician needs to be aware of the patient's past history of trauma or loss and the symptoms that may overlap in addiction and mental illness; while the patient needs constant encouragement and motivation from family and friends that they can heal and feel well again.