Self-reported experiences is an excellent way of diagnosing clinical depression. Herein, a client may describe her/his feelings of hopelessness, guilt or experiences in the day to day life, which may help a clinical psychologist or a psychiatrist to come to a diagnosis. Such a technique may require multiple visits to a professional as the client forms a therapeutic relationship with the psychologist and explains her/his experiences. Constant interaction between the client and the professional may help the psychologist to make the diagnosis and proceed to a proper treatment. A person with depression may state his/her experiences in terms such as hopelessness, guilt, being unloved or may present feelings or thoughts about suicide and self harm.

A therapist or a professional may observe the client over a period of time to make the diagnosis. Herein, the professional will ask the client to make a few visits wherein she/he may intervene in the client’s life and notice the symptoms that can be counted under the criteria for diagnosing clinical or major depression. The professional will see if the client displays three typical depressive symptoms; depressed mood, reduced energy and anhedonia. The professional will notice the changes in the client’s normal life and whether the changes have lasted for at least two weeks.

The professional can also make diagnosis through the method of interview. In this case, a close family member or a close friend of the client can accompany the client for at least one visit and describe the changes in client’s lifestyle pattern. The friend or family member may discuss the possible reasons behind the depression symptoms (like loss of loved one, stress, relationship issues, postpartum depression etc). The interview is an easy procedure and the person just have to answer some questions through which the therapist can analyze the situation. This also allows the professional to know the changes in client’s sleeping patterns, her/his loss in once pleasurable activities and changes in appetite or presence of suicidal tendencies.

The professional can perform a mental status examination of the client. Herein, the client pays a few visits to the therapist before the treatment begins and the professional follows a structured way of observing and describing client’s current state of mind through observation of behavior, mood, speech, thought, perception, cognition and insight. The procedure makes a detailed assessment of client’s current state of mind.

There are no laboratory tests that can determine depression, but the psychologist in certain cases may ask the client to undergo a range of laboratory tests to check for physical conditions like brain lesions, injury, tumors, substance abuse, etc., that may cause similar symptoms. Depending upon the number of tests, the client may have to spend a day at a clinic to undergo these tests. Most of these tests are non-invasive in person’s privacy.

This is a self-reporting test wherein the client is asked to take a small written test to diagnose major depression. The inventory consists of a self report questionnaire in which the client is provided with several options to select her/his answer. The test requires one sitting with the psychologist and is relatively easy. It allows the professional to understand the severity as well as the cause of depression. The test can even be taken at home and is available free of charge and can be downloaded from internet with manual and scoring instructions.

In a few cases, the client may have to visit a hospital for an EEG or Electroencephalogram scan to record her/his electrical activity of the brain, which may allow the professional to rule out presence of abnormality in brain functioning. This will also allow the psychiatrist to understand that how the neurotransmitters like dopamine are functioning in the client’s brain and prescribe required medications.