Which Depression Test Should You Take? SDS vs BDI vs SCL-90 vs GDS-15

There is no single best depression test, because these scales were built for different jobs. Some screen one symptom group quickly, some profile many dimensions at once, and one is designed specifically for older adults. Picking the wrong one usually costs you time, not accuracy: a 90-question profile is a poor choice when you only want a five-minute check, and a five-minute screen is a poor choice when you want a full picture.

This site carries six depression-related scales: the SDS, the BDI, the CES-D, the HADS, the SCL-90, and the GDS-15. They are all self-report questionnaires, which means they record what you say about your own experience. None of them can diagnose depression on its own. What they can do is give you a structured result you can compare over time or discuss with a professional.

The table below uses this site’s own versions: question counts and times are the ones shown on each test page. Use it to narrow the choice, then read the three steps that follow.

Start with the length question, because it decides whether you will finish. The GDS-15 takes about 3 minutes, four of the scales take about 5 minutes, and the SCL-90 takes about 20. If you are short on patience today, a short scale you actually finish beats a long scale you abandon halfway.

Then look at the focus. The SDS, BDI, and CES-D focus on depressive symptoms. The HADS splits its 14 questions evenly between anxiety and depression, which helps when both are present. The SCL-90 is not a depression test in the narrow sense: it profiles nine symptom dimensions, of which depression is one. The GDS-15 is the only one built for older adults, with yes-or-no answers and almost no physical-symptom questions.

If you still cannot decide, start with the SDS. It is the most widely used general depression screen on this site, it takes five minutes, and its result pairs naturally with the SAS anxiety scale when anxiety is also present.

First, a high score is not a diagnosis. Screening scales are designed to catch possible cases, which means they deliberately cast a wide net. A high result says “look closer”, and looking closer means a professional conversation, not a label you give yourself.

Second, scores from different scales are not interchangeable. The SDS, BDI, and CES-D count different items in different ways, so a score on one cannot be translated into a score on another. Compare a scale with itself over time instead.

Third, do not hand an older adult a general adult scale by default. Physical symptoms such as poor sleep, low energy, or aches overlap with depression items and can inflate the score. That overlap is exactly why the GDS-15 keeps its questions short, yes-or-no, and free of most physical symptoms.

Write down your score and the date. A single result is a snapshot; two results a few weeks apart show a direction. If you retake a scale, use the same one under similar conditions.

If low mood has lasted for two weeks or more, if it interferes with work, study, sleep, or relationships, or if it includes thoughts of harming yourself, talk to a mental health professional or a doctor soon. A test result is useful preparation for that conversation: it gives you concrete items to describe instead of a vague “I feel bad”.

If the result is low but you still feel something is off, trust that too. Scales miss things, especially when symptoms are new or mainly physical. A low score rules out nothing on its own.