Comorbid psychiatric disorders Comorbid psychiatric disorders commonly go undetected in the<unk>  of depression. If left untreated, the symptoms of these disorders can interfere with both evaluation and<unk> . Anxiety disorders are one of the most common disorder types associated with<unk> . The two disorders commonly co-exist, and have some similar symptoms. Some studies have shown that patients with both MDD and panic disorder are the most likely to be nonresponsive to<unk> . Substance abuse may also be a predictor of<unk> . It may cause depressed patients to be noncompliant in their<unk> , and the effects of certain substances can worsen the effects of depression. Other psychiatric disorders that may predict<unk>  include attention deficit hyperactivity disorder, personality disorders, obsessive compulsive disorder, and eating disorders. Comorbid medical disorders Some people who are diagnosed with<unk>  may have an underlying undiagnosed health condition that is causing or contributing to their depression. Endocrine disorders like hypothyroidism, Cushing's disease, and Addison's disease are among the most commonly identified as contributing to depression. Others include diabetes, coronary artery disease, cancer, HIV, and Parkinson's disease. Another factor is that medications used to treat comorbid medical disorders may lessen the effectiveness of antidepressants or cause depression symptoms. Features of depression People with depression who also display psychotic symptoms such as delusions or hallucinations are more likely to be<unk><unk> . Another depressive feature that has been associated with poor response to<unk>  is longer duration of depressive episodes. Finally, people with more severe depression and those who are suicidal are more likely to be nonresponsive to antidepressant<unk> .
Treatment-resistant depression
Long-term depression
Recurrent brief depression
Outline of bipolar disorder
Chronic hallucinatory psychosis
Double depression
Mass psychogenic illness
Late life depression