Patients who have been diagnosed as suffering from schizophrenia may at times, during the course of their illness, suffer from significant and discomforting depressive symptoms. This is most often the case in patients suffering from so-called negative schizophrenia. The negative symptoms that give this syndrome its name describe a series of deficits and are in many ways similar to the symptoms of depression. Thus these patients lack motivation, are lethargic, find it difficult to concentrate and experience a restricted range of emotional responses, which is very evident to others around them. The treatment of their symptoms, however, requires quite a different approach from the treatment used for the symptoms of common depressive illness.
Another group of sufferers from schizophrenia experience mood disorders including depression in the aftermath of their illness; this is often associated with a realization of the implications of their illness for their long-term well-being.