The depressed person then becomes angry at his own helplessness. The common thread that underlies much of depression is a sense of loss. This sense of loss may be real or imagined. Simple things like not eating properly and not getting proper rest can cause depression. A reaction to certain drugs can affect a person's moods.
All drugs affect the body and the mental processes in some way.
If a drug results in the brain or nervous system toxicity, extreme depression could be the result. Toxic depression results when a person takes too much of a drug or sedative over an extended time. This kind of depression and drug toxicity will clear up in a day or so after the drug is no longer in the system. If you become depressed while taking a medication consult your medical doctor. Others such as glandular disorders, low thyroid, hyperthyroidism, excessive ovarian hormonal irregularities can cause depression.