A mood disorder is a category of mental health issue that involves persistent or cyclical mood changes, usually low mood for a specific period of time. The emotional state is inconsistent with surroundings or experiences, or distorted out of proportion to the person’s situation. For example, grief can trigger a mood disorder, but the experience of grief after a personal loss is not itself a mood disorder. About 9.5 percent of the adult population in the US experiences a mood disorder in a given year, while 4.3 percent are considered “severe” mood disorders, meaning they are long-lasting, intense, or chronic.

Anyone can develop a mood disorder, although people who have a family history of mental health or substance use disorders are more likely to develop these conditions than other people. Mood disorders can appear at nearly any age, from early childhood to later adulthood. For the most part though, these conditions appear in adolescence or young adulthood, with the average age of onset listed as age 30. Women are twice as likely to be diagnosed with a mood disorder as men. It is important to get appropriate medical and psychological help for these conditions, because untreated mood disorders are correlated with an increased risk of substance abuse problems.

There are two basic types of mood disorders: depression and bipolar disorder. However, there are different types of conditions in both of these categories.

Types of Mood Disorders

  • There are two overarching categories of mood disorders, with several subsets of conditions within each category. Depression-based mood disorders include:

    • Major depression: This is a prolonged period of sadness or anhedonia (lack of feeling) that does not lift for at least two weeks. It can also feature suicidal ideation and some anxiety. In some cases, major depression can eventually lift, given time, but it is better to seek treatment if feelings of disinterest, loss of pleasure, sadness, or guilt persists.
    • Dysthymia: This is chronic depression, which does not lift without help, for at least two years.
    • Psychotic depression: This involves severe depression symptoms alongside psychosis, including delusions and hallucinations.
    • Seasonal affective disorder: This is a condition in which a person experiences mood changes related to seasonal changes. The more common form involves feeling depressed through the winter, then experiencing mood lifting in the summer. However, some people experience the opposite, potentially due to loss of sleep from too much daylight in the summer.
    • Postpartum depression: This form of major depression, sometimes with psychotic symptoms, can affect new parents after the birth of a baby. This is primarily diagnosed in new mothers, but new fathers can also experience this condition.
  • Bipolar-based mood disorders, which involve cycling through extreme depression and feeling up, or mania, include:
    • Bipolar 1 disorder: This condition is characterized by at least one major manic episode and one major depressive episode. Depression must occur either before or after mania, and the mania must be serious enough that the person is hospitalized. While an initial depressive episode may not be so obviously intrusive on the person’s life, the manic episode will be very intrusive and disruptive.
    • Bipolar 2 disorder: This disorder involves less severe manic episodes that are not intrusive on the person’s life, interspersed with depressive episodes. The individual will receive a diagnosis when they display one major depressive episode lasting at least two weeks and one hypomanic episode. While the condition is overall disruptive to the person’s life, they are able to continue through their daily routines while experiencing manic and depressive episodes, typically. Bipolar 2 disorder is often initially mistakenly diagnosed as major depression.
    • Cyclothymic disorder: This disorder involves emotional ups and downs that are similar to other bipolar disorders, but less extreme.

    Mood disorders can be triggered by an underlying medical condition, such as a traumatic brain injury or cancer. They can also be triggered by substance abuse, or vice versa.

Correlation between Mood Disorders and Addiction

According to an article on PubMed, mood disorders and substance abuse are the most common co-occurring disorders. A co-occurring disorder is a condition characterized by both a diagnosable mental health condition and a substance abuse issue at the same time. The article noted that 32 percent of people with a mood disorder were also diagnosed with a substance abuse disorder; 16.5 percent had co-occurring major depression and alcohol use disorder, while 18 percent had both major depression and other drug use disorders. Among people with diagnosed bipolar disorder, 56 percent abused substances. One report suggests that 61 percent of people with bipolar I struggle with some form of substance abuse, and 48 percent of those with bipolar II develop substance abuse; about 27 percent of those with major depressive disorder develop substance abuse problems.

There are many potential reasons for mood disorders and substance abuse to overlap. Genetic predisposition or environment during childhood could play a role; people who have family members, especially parents or siblings, with either a substance use or mood disorder are more likely to develop either disorder at some point in their lives. One theory suggests that overlapping neurological pathways reinforce self-medicating behaviors, because drug abuse changes brain chemistry which, on a short-term basis, could alleviate some of the emotional struggles related to the mood disorder.

Regardless of how the two conditions work together, one can trigger the other. There are two fundamental theories of which condition leads to the other.

  1. Mood disorder leading to substance abuse: One of the original theories regarding the correlation between substance abuse and mood disorders suggested that people who struggled with mental health issues, especially bipolar disorder, depression, or anxiety, were more likely to turn to self-medicating through alcohol or other drugs. Central nervous system (CNS) depressants, like alcohol, marijuana, and narcotics, can alleviate stress related to anxiety or anxiousness associated with depression or mania. Stimulants, such as nicotine or cocaine, can elevate mood so a person may feel, temporarily, like they are happy or energized. However, intoxicating substances wear off, and withdrawal symptoms can make symptoms of the original mood disorder worse.
  2. Substance abuse triggering mood disorder: Long-term and/or high-dose substance abuse fundamentally changes the chemical balance of the brain, and both together can affect the brain’s structure, leading to a loss of brain matter or changes to brain structures. This is particularly problematic for children or adolescents who abuse substances, as their brains are still changing. This can induce a mood disorder, which could persist after the person detoxes and could require separate psychotherapeutic treatment. While many people who experience this specific condition have some risk factors for a mood disorder, the mental health condition is more likely to clear up when they detox from the substance.

Help for Co-Occurring Mood Disorders and Substance Use Disorders

residential treatmentThe intricate balance of brain chemistry that can lead to a dual diagnosis of a mood disorder and substance use disorder is becoming better understood by medical researchers. Thanks to this research, rehabilitation programs are increasingly able to help people who struggle with these co-occurring disorders overcome both conditions.
It is important for a person struggling with substance abuse to safely detox, and for people with a co-occurring mood disorder, this could mean additional medical supervision to monitor symptoms of the mood disorder. In some cases, appropriate psychiatric medications may be prescribed to ease symptoms.

After detox, participation in a comprehensive rehabilitation program is needed to address the underlying issues behind both co-occurring disorders. Therapy is often focused on developing better coping mechanisms to manage symptoms of the mood disorder. The National Institute on Drug Abuse (NIDA) recommends remaining in a rehabilitation program for at least 90 days. After that, many people with mood disorders will continue working with a therapist, although they may see the therapist less frequently over time as they better learn to manage their disorder on an ongoing basis.