Although clearly not identical emotional states, mental health research suggests that depression and anxiety often coexist because they can be caused by the same or similar factors.
- Genetic Factors Genetic factors contribute to 40 percent of the predisposition to depressive and anxious symptoms, with 60 percent being attributed to environmental, noninherited factors.” “Especially with anxiety, more so than depression, there often is some family history, and so therefore we think that there may be some genetic predisposition to this,” Connolly explains.
- Environmental Factors Also referred to as social factors, these include experiences like trauma or neglect in early childhood, and current stressors such as relationship difficulties, unemployment, social isolation, and physical illness. People who have post-traumatic stress disorder (PTSD), an anxiety disorder, are particularly likely to also develop depression, according to the National Institute of Mental Health (NIMH).
- Pain Chronic pain, and particularly disabling pain syndromes such as fibromyalgia, irritable bowel syndrome (IBS), low back pain, headaches, and nerve pain, are closely linked to psychological distress, including both anxiety and depression, notes Harvard Health. In fact, they say, research suggests that “pain shares some biological mechanisms with anxiety and depression.”
Ultimately, the core of the double disorder is “a cycle,” says Connolly. “When you get anxious, you tend to have this pervasive thinking about some worry or some problem and you feel bad about it. Then you feel like you’ve failed, and you move to depression.” Similarly, she adds, “people who are depressed often feel anxious and worried, so one can trigger the other.”
According to the current Diagnostic and Statistical Manual of Mental Disorders (DSM-V), the standard classification of mental disorders used by mental health professionals in the United States, anxiety and depression can share several common symptoms, including, but not limited to:
- Being easily fatigued
- Difficulty concentrating or mind going blank
- Sleep disturbance (difficulty falling or staying asleep; restless, unsatisfying sleep)
Other signs that a person may suffer from both anxiety disorder and depression include:
- Constant, irrational fear and worry
- Physical symptoms like rapid heartbeat, headaches, hot flashes, sweating, abdominal pain, and/or difficulty breathing
- Changes in eating, either too much or too little
- Persistent feelings of sadness or worthlessness
- Loss of interest in hobbies and activities
- Inability to relax
- Panic attacks