A recent study review conducted by Australian researchers points to a strong degree of overlap between diagnosable substance problems and mental health problems classified as mood disorders or anxiety disorders. Statistically speaking, any given person affected by drug- or alcohol-related abuse or addiction has increased chances of developing certain mental health issues not directly related to substance use. In a study review published in May 2015 in the journal Drug and Alcohol Dependence, researchers from Australia\u2019s University of Sydney and University of Western Sydney examined the degree of overlap between diagnosable drug or alcohol problems and the occurrence of mental health conditions classified as anxiety disorders or mood disorders. These researchers found a strong connection between certain substance problems and certain mood- and anxiety-related conditions. Substance Problems Substance problems typically occur for one of two reasons. In some cases, an alcohol, drug or medication consumer begins a pattern of excessive or inappropriate intake based on a desire to feel heightened levels of a powerful form of pleasure called euphoria. In other cases, an alcohol, drug or medication consumer bases his or her pattern of excessive or inappropriate intake on a self-medication motive linked to a general desire to feel better or a more targeted desire to ease the effects of specific symptoms or conditions. Whatever the underlying motivation, an established pattern of substance misuse can seriously damage the ability to maintain a stable daily routine or experience a sense of well-being. This fact holds true whether an affected person develops a physical addiction to the substance in question or develops symptoms of non-addicted substance abuse. Under modern terms established by the American Psychiatric Association, both substance addiction and substance abuse belong to a single diagnostic entity called substance use disorder. Mood Disorders A mood disorder is any officially diagnosable mental health condition that qualifies as a depressive disorder or a bipolar disorder. The American Psychiatric Association (APA) recognizes eight depressive disorders: isolated or recurring major depression, persistent depressive disorder, disruptive mood dysregulation disorder, premenstrual dysphoric disorder, substance\/medication-induced depressive disorder, \u201cother\u201d specified depressive disorder and unspecified depressive disorder. The seven bipolar disorders recognized by the APA are bipolar I disorder, bipolar II disorder, cyclothymic disorder, bipolar and related disorder due to another medical condition, substance\/medication-induced bipolar and related disorder, \u201cother\u201d specified bipolar and related disorder, and unspecified bipolar and related disorder. Anxiety Disorders Anxiety disorders are APA-recognized mental health conditions centered on some form of life-impairing worry, fear or dread. Currently, there are 12 such conditions: panic attack, panic disorder, generalized anxiety disorder, agoraphobia, specific phobia, social anxiety disorder, selective mutism, separation anxiety disorder, anxiety disorder due to another medical condition, substance\/medication-induced anxiety disorder, \u201cother\u201d specified anxiety disorder and unspecified anxiety disorder. Two well-known conditions once classified as anxiety disorders\u2014obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD)\u2014now have their own separate diagnostic categories (respectively known as obsessive compulsive and related disorders and trauma- and stressor-related disorders). Degree of Overlap In the study review published in Drug and Alcohol Dependence, the researchers used an analysis of studies published in six major databases between 1990 and 2014 to help determine how often adults with substance use disorder also develop diagnosable cases of a depressive disorder, bipolar disorder or anxiety disorder. All told, the researchers identified 22 separate studies that provided real-world information on the chances of developing overlapping symptoms of substance use disorder and a mood disorder or an anxiety disorder in any given year or over the course of a lifetime. After completing their analysis, the researchers concluded that the strongest area of overlap between substance use disorder and a mood or anxiety disorder is the connection between illicit drug-related abuse\/addiction and major depression; individuals with this type of substance problem develop major depression almost four times more often than the general public. Other prominent areas of overlap between substance use disorder and a mood or anxiety disorder include the connection between illicit drug-related abuse\/addiction and all forms of anxiety disorder (associated with an anxiety disorder risk almost three times higher than the general public), the connection between alcohol abuse\/addiction and major depression (associated with a major depression risk roughly 140 percent higher than the rest of the population) and the connection between alcohol abuse\/addiction and all forms of anxiety disorder (associated with an anxiety disorder risk roughly 111 percent higher than the rest of the population).