It's estimated about 18.6 percent of adults are affected by both ADHD and depression. The symptoms of depression include the loss of interest in familiar activities, feeling tired a lot of the time, and experiencing unplanned changes in sleep and eating habits. Some people struggling with depression describe feeling numb to their own life, disconnected from others, and alone even when they are not. They may also feel agitated, with a sense of wanting to get out of their own skin.Depression is different from the "blues," or sadness that follows the end of a relationship or a period of grief after a loved one dies, although those can turn into depression if they last for the long term."Sometimes with situations like bereavement, a breakup, or a job loss, it can snowball into a clinical depressive episode," says Roberto Olivardia, PhD, a clinical associate at McLean Hospital and lecturer in psychology at Harvard Medical School. Dr. Olivardia is a member of CHADD's Professional Advisory Board. "So, if someone notices after about a two-week period that these symptoms are still happening, then they should definitely be talking to someone."In both clinical and community settings, the clinical significance of ADHD and depressive disorders is substantial when they co-occur. ADHD is a chronic disorder that often persists into adulthood; it is also among the most common psychiatric disorders. In DSM-5, the more lenient criteria for age of onset and lower required number of symptoms for adult ADHD will likely increase the rates of ADHD diagnoses.In adults, episodes of MDD cause significant morbidity and mortality, but when they occur with ADHD, such episodes are more prolonged, more likely to result in suicidal behaviors and hospitalizations, and more likely to convert from unipolar to bipolar mood disorders. The impact of comorbid depression on ADHD response has not been assessed, but studies of patients with bipolar disorders suggest that ADHD treatment may exacerbate untreated mood disorders. Because ADHD typically begins several years before the first unipolar depressive episode, earlier identification and treatment of ADHD may affect the risk of depression.Because children and adults with ADHD struggle with focusing, organizing tasks, and feeling restless, they might experience sadness, guilt, irritability, low self-confidence and helplessness. In some cases, these symptoms can signal depression.Some experts assert that up to 70% of people with ADHD will seek treatment for depression at least once. One study at the University of Chicago reported that adolescents with ADHD are ten times more likely to suffer from depression than adolescents without an ADHD diagnosis.