Major depressive disorder (MDD) has several complications and comorbidities. Complications are issues that arise due to a health condition or its treatment. They are not formal medical diagnoses. Drug side effects, behavior changes, and social impacts are all examples of complications.1,2
Comorbidities are co-existing medical conditions. An example would be having both MDD and diabetes. These diagnoses can occur at the same time or one after the other.1,2
Complications can lead to comorbidities. For example, weight gain as a side effect of a medicine may increase a person’s risk of developing heart disease. Comorbidities may increase the risk of complications, too. The relationship between complications and comorbidities can be complex. There are also a lot of experts who still do not know about MDD and its long-term outcomes.1-4
Several common complications of MDD are described below. But this is not a complete list. Talk with your healthcare team if you are having issues that impact your daily life or that concern you.
Substance use
Examples of substances a person with MDD may use include tobacco, alcohol, and recreational drugs. Although the link between depression and substance use is strong, it is not well understood.3-6
Some experts think similar areas of the brain are involved in the development of depression symptoms and the desire to use substances. Several of these brain processes are thought to be involved in feeling pleasure, reward, and cravings.3-6
Depression and substance use also share similar risk factors. Some of these factors are past trauma, severe stress, and multiple long-term medical issues. Over time, occasional substance use can begin to affect daily functioning and overall health. At that point, a person may be diagnosed with substance use disorder (SUD). SUD would then be a comorbidity of MDD.3,5,6
Relationship issues
The symptoms of depression can lead to relationship challenges. Not participating in usual hobbies, not wanting to socialize, and having low energy can impact the desire to see loved ones. Substance use issues, trouble at work, and other physical symptoms can get in the way of connecting with others, too. And sexual side effects of antidepressant drugs can impact romantic or intimate relationships.1,7,8
All kinds of relationships can be affected when a person has MDD. This includes friendships, parent-child bonds, and professional ties. And the low self-esteem, stigma, and intense feelings of rejection that can come with MDD impact the ability to form new relationships.3,4,7
Sometimes, loved ones without a history of depression do not understand the struggles the condition can bring. This can be another source of strain.3,4,7
Employment challenges
Low motivation, trouble concentrating, and sleepiness can make it hard to carry out daily tasks. One important area that might be impacted is work. Depression is a leading cause of lost productivity and absenteeism.9,10
In some cases, people with MDD may not want to talk to their supervisors about their personal health. This lack of communication can lead to conflict when coworkers or managers do not understand why work quality or quantity has changed. Eventually, people with MDD may be at risk of losing their job.9
The good news is that there are resources and protections to help people with MDD deal with workplace challenges. Talk with your healthcare team to learn more about them.9
Financial problems
Healthcare can be expensive, especially when managing a potentially long-term condition like MDD. Health insurance can be frustrating to navigate. Medicines, appointments, therapy, and other costs may add up quickly. Financial strain is even more challenging if a person is unable to work due to MDD.10
This can become a difficult cycle, as stress from financial worries can make MDD symptoms even worse. However, like with employment, there are support options available for those in need. Some pharmaceutical companies and large retailers offer reduced-cost drug options for those who qualify. Case managers and social workers at your doctor’s office also may be able to help with immediate needs like food, shelter, or transportation.11,12
Somatic complications
The mind is connected to many other functions in the body. That means that mood changes can lead to other physical symptoms. Some of these symptoms can go on to worsen depression. These physical symptoms are sometimes referred to as somatic complications.13-17
For example, low energy or lack of motivation can make it hard to exercise and eat well. This leads to weight gain. Some antidepressant drugs increase appetite or lead to weight changes, too. Over time, inactivity, poor diet, and obesity can increase the risk of developing other health conditions like diabetes or heart disease.13
It is common for people with depression to have gastrointestinal (GI) issues. These issues include diarrhea, constipation, nausea, and general belly pain.3,14
Sleep is often impacted by MDD, too. Some people have trouble sleeping (insomnia) or sleep too much (hypersomnia).15
In addition, pain and depression often go hand in hand. Although the link is not completely understood, pain perception and mental health distress can feed off of one another. It makes sense that when we are in pain, our mood is worse.16,17
Some health conditions that cause chronic pain, like arthritis, increase the risk of developing depression. But some experts think people with depression may perceive pain more intensely than those without depression. This can lead to a constant cycle of worsening discomfort.16,17
Self-harm or suicide
The risk of having thoughts of harming themselves or others is higher for people with MDD. They also may have self-harm behaviors, like cutting or burning.18,19
In some cases, thoughts of self-harm can be severe and lead to no longer wanting to live. As many as 2 out of every 3 people with MDD will think about taking their own life at some point. Thankfully, far fewer actually complete suicide. The risk is highest for men and those who have had past attempts.18,19
If you or a loved one are having thoughts of harming yourself or no longer wanting to live, seek immediate support. You can reach the 988 Suicide and Crisis Lifeline 24 hours a day by texting or calling 988 in the United States.20