Suboxone causes a variety of side effects, but depression isn't usually one of them.
If you're feeling low and sad during opioid use disorder (OUD) recovery, you can get help. But know that your medication is probably not to blame.
Known Suboxone side effects include sedation, nausea, headache, and constipation. There is no known link between taking Suboxone and developing depression.
We do know that people with an OUD often have co-occurring mental health issues, including depression. In fact, people are often depressed because of their opioid use disorder, and using evidence based treatments like MAT can treat the OUD and subsequently cause improvements in depression.
Life with OUD can be challenging. Many Suboxone patients experience anxiety, depression, and other mental health concerns. But often, those problems pre-date the Suboxone therapy itself and are more a result of concurrent opioid use disorder.
Research shows that opioids can trigger depressive episodes in people with no prior history of depression.
The medications prompt your brain cells to release feel-good chemicals. In time, they won't put those chemicals into your blood without drugs. In the absence of chemicals, you may feel depressed.
Researchers also say that people with mood and anxiety disorders are at higher risk of OUD. You may use these drugs as a form of self-medication for your mental health. Or you may be genetically inclined to misuse drugs if you have genes that spark mental health problems. For this reason, OUD and mental health concerns like depression often occur together.
If you experience depression in the course of your treatment, you should always talk to your doctor. But know that treating your opioid use disorder is one of the best ways to combat depression. The Suboxone itself is rarely to blame. Instead, the etiologies of depression are usually multifactorial.
The medications your doctor uses to address addiction (including methadone and buprenorphine) are often linked to improvements in depression. These medications can correct chemical imbalances within your brain cells, helping you to feel more like yourself.
Your doctor can also use antidepressant medications to help you feel less depressed. These medications are safe to use while you're taking Suboxone.
Therapy can also help to ease depression. There are multiple forms and types of therapy for depression, including cognitive behavioral therapy, interpersonal therapy, group therapy, etc. 
Your doctor might add these therapies to your treatment plan.
Depression is a relapse risk factor, so it's critical for your doctor to understand how you're feeling as you recover. Speak up and talk about your depression to get the help you need. With assistance, you’ll learn how to manage your depression and your opioid use disorder at the same time. Treating one often treats the other.