What is the SCL-90 test, what do its nine subscales measure, and how are the scores and global severity index read? A clear guide for anyone completing it.
You arrive for your first appointment, and a professional who doesn't know you yet asks you to fill in a long form with the pen in your hand: ninety items. "Headaches", "Feeling that others are watching you", "Sudden attacks of fear", "Feeling lonely"... Next to each one, five options. As you fill it in, you find yourself wondering: Why so many questions? Some of these items don't apply to me at all, so why are they being asked? The SCL-90 test, generally known in Turkish as the Symptom Checklist (Belirti Tarama Listesi), is a self-report scale used to review a wide range of psychological symptoms in a short time. In this article I explain what the scale measures, what the subscales mean, how the scores are calculated and interpreted, and why the names of some subscales should not frighten you.
What Is the SCL-90 Test?
The SCL-90 is a symptom screening scale developed in the 1970s by the American psychologist Leonard Derogatis and his colleagues, later revised and renamed the SCL-90-R. It has been adapted into Turkish and has been widely used in Turkey for many years in hospitals, university counselling centres, private clinics and research.
The aim of the scale is to see, within a broad framework, the psychological and physical symptoms a person has experienced recently and how distressing they are. Unlike scales that focus on a single problem, it screens many areas together, from depression to anxiety and from physical complaints to sensitivity in relationships. This is why it is particularly favoured in an initial assessment, to see quickly which areas a person is struggling with.
The scale is not a diagnostic tool. It is a screening tool: it looks for an answer to the question "Where do we need to look?" It shows which areas need to be discussed in detail and guides the clinical interview.
How Is the Scale Completed?
The SCL-90 test contains ninety items. Each item describes a symptom, and the person is asked to mark how much that symptom has bothered them recently, usually over the last week including today (depending on the form used, this period may be somewhat longer). The options have five levels:
- Not at all
- A little bit
- Moderately
- Quite a bit
- Extremely
Completing it takes most people between fifteen and twenty-five minutes. A few suggestions will make it easier:
- Don't think for too long. The first answer that comes to mind is usually the most accurate. Weighing up every item at length is tiring and blurs your answers.
- It is normal for some items not to apply to you. Because the scale screens very different areas, some items are expected to be "Not at all". This does not mean the scale is not suitable for you.
- Stick to the time period asked about. Answer the question "How has it been recently?", not "Have I always been like this?"
- Ask if you don't understand an item. Some statements may be hard to understand, especially for older people or those who don't read much. The practitioner can explain the item.
What Do the Nine Subscales Measure?
The items are divided into nine core symptom areas, or subscales. In addition, there are a few extra items (such as sleep, appetite and feelings of guilt) that do not belong to any subscale but are clinically important.
- Somatisation: Physical complaints such as headaches, dizziness, nausea, muscle aches and shortness of breath. This reflects how stress is felt in the body.
- Obsessive-compulsive symptoms: Unwanted thoughts that won't leave the mind, a need to check things again and again, difficulty making decisions and concentrating.
- Interpersonal sensitivity: Feeling inadequate, inferior or uncomfortable around others; sensitivity to criticism and rejection.
- Depression: Sadness, loss of interest, hopelessness, low energy, feelings of worthlessness.
- Anxiety: Tension, nervousness, trembling, palpitations, sudden feelings of fear.
- Anger-hostility: Getting irritated quickly, angry outbursts, an urge to break things or shout.
- Phobic anxiety: Intense fear and avoidance in particular places or situations (crowds, public transport, open spaces, leaving home alone).
- Paranoid ideation: Difficulty trusting others, feeling watched or talked about, the thought of not being given the recognition one deserves.
- Psychoticism: Loneliness, feeling cut off from others, and unusual experiences such as feeling that one's thoughts are controlled or known by others.
These areas are not entirely independent of each other. Let's say a student who has got into university, moved to another city and is living in a hall of residence applies to the counselling centre. On their form, the interpersonal sensitivity, depression and psychoticism subscales come out high. The picture that emerges in the interview is not so much a serious mental disorder as the intense loneliness of not knowing anyone in a new city, seeing oneself as inferior to others, and the sense of disconnection that comes from being away from family for the first time. The same scores may correspond to an entirely different story in another person.
Who Takes the SCL-90 Test, and When?
The symptom checklist is a tool that can be used with adults from late adolescence onwards. In Turkey, the places you are most likely to come across it are:
- Hospital psychiatry outpatient clinics, before or after the first consultation
- University counselling and guidance centres, when a student first applies
- Private clinics and psychologists' practices, as part of the initial assessment
- Employee assistance programmes or corporate mental health screenings in workplaces
- Scientific research, to measure participants' general mental state
The scale is usually used not on its own but alongside a clinical interview and, where necessary, supported by other scales. For people who have difficulty reading, have a vision problem or do not speak Turkish as their first language, the items may be read aloud by the practitioner; adaptations like this need to be noted when the result is assessed. During a very severe crisis, for example intense panic or the first days of deep grief, listening to the person and ensuring their safety takes priority over completing a ninety-item form.
How Are SCL-90 Test Results Calculated?
Each item scores between 0 and 4 depending on the option marked. Scoring provides information at two levels.
Subscale scores: The scores for the items in each subscale are added up and divided by the number of items to give an average. This makes subscales with different numbers of items comparable with each other.
Global indices:
- Global Severity Index (GSI): Obtained by dividing the total score for all items by ninety. It is the most widely used indicator of the overall level of distress a person reports.
- Positive Symptom Total (PST): The number of items marked as anything other than "Not at all"; it shows how many different symptoms the person reports.
- Positive Symptom Distress Index (PSDI): The average intensity of the symptoms marked; it shows how severely the person experiences their symptoms.
This distinction matters. Let's say two people have the same global average. The first has marked many symptoms at the "a little bit" level; the second has marked only a few symptoms, but at the "extremely" level. The first person's distress may be widespread but mild, and the second's narrow but intense. These two pictures call for different questions and different approaches.
How Are the Scores Interpreted?
In a widely used interpretation in Turkey, subscale averages above 1 may indicate symptoms in that area that warrant attention, and averages above 2 a markedly high level. These thresholds are a useful guide, but they are not absolute. The meaning of the result is determined together with the person's age, their circumstances and what they describe in the clinical interview.
When reading the results, it is important to keep some points in mind:
- The profile is more meaningful than any single score. Which subscales are raised and which stay low says more about the nature of the problem. For example, a profile in which anxiety, phobic anxiety and somatisation rise together may suggest panic-like complaints; but this is only a hypothesis to be explored in the interview.
- Physical illnesses can affect the result. Someone with chronic pain, asthma or a hormonal problem may score high on the somatisation subscale regardless of psychological causes.
- The language of distress varies by culture. In Turkey, many people describe their emotional distress in bodily terms such as "My chest feels tight inside", "A weight has settled on my heart" or "My headache never goes away." So a high score on the somatisation subscale may show that the person is experiencing their sadness or anxiety through their body. This is a valuable starting point in therapy for learning to put names to feelings.
- Living conditions shape the answers. Someone working in a workplace where mobbing takes place may mark the item "Feeling that others are watching you or talking about you" highly, reflecting a real situation rather than their thought processes.
- A generally high score may be a sign of general distress. If a person is going through a very difficult period, almost all the subscales may rise. In this case, the differences between subscales are more informative than the individual values.
Rather than receiving your result simply as a list of scores, it is far more useful to discuss with the professional what these numbers correspond to in your life.
A symptom checklist is not a summary of what you have been through but a table of contents showing where you might begin to tell your story.
Don't Let Names Like "Psychoticism" and "Paranoid Ideation" Frighten You
Seeing subscale names such as "psychoticism" or "paranoid ideation" in a results report unsettles many people. These names come from the clinical language of the period in which the scale was developed and do not mean the same as their everyday meanings.
A large proportion of the items on the psychoticism subscale relate to feeling cut off from people, lonely or alienated. A raised score on this subscale often points not to a psychotic disorder but to intense loneliness, withdrawal or a sense of distance linked to severe stress. Similarly, the paranoid ideation subscale covers experiences of finding it hard to trust people and of feeling vulnerable; someone who has been betrayed, cheated on or treated unfairly at work may mark these items highly.
Of course, raised scores on these subscales are addressed carefully in the interview. But don't draw a diagnosis for yourself from a word you see in a report; put your questions to the professional who carried out the assessment.
How Is It Used in Assessment and Therapy?
The SCL-90 test helps map out the topics to discuss with the person, particularly in the first appointments. People sometimes find it hard to raise the issue they are really struggling with in the interview, but marking it on a form may feel easier. For example, someone who comes because of insomnia may mark on the form that they feel worthless or cry often, and this is an important door to open in the interview.
During therapy, the scale can be given again at intervals. Comparing the initial profile with the profile a few months later shows in concrete terms which areas have improved and which are still difficult. When a more detailed assessment is needed, scales focusing on a particular area come into play; for example, if depressive symptoms stand out, tools such as the Beck Depression Inventory can be used. If you are curious about how psychological tests work in general, you can take a look at the article what is a psychological test.
In individual therapy, the results of the scale are considered together with the person's goals. A high somatisation score can open the door to work on how bodily sensations are interpreted, and a high interpersonal sensitivity score to work on beliefs about criticism and rejection. If thoughts of self-harm emerge in the results or in the interview, this is addressed as a priority; if you feel you are in immediate danger, don't hesitate to call 112 (emergency services).
Frequently Asked Questions
I scored high on one subscale. Do I have that condition?
No, that conclusion cannot be drawn on its own. Subscales show the intensity of symptoms; they do not make a diagnosis. For example, a high score on the depression subscale shows that depressive symptoms need to be assessed carefully; a diagnosis is made through a clinical interview.
If I want to make myself look better or worse than I am, will the scale notice?
The symptom checklist does not contain special scales that capture response distortions in detail. The value of the result therefore depends largely on your answering sincerely. Presenting yourself as different from how you are makes it harder to plan the support that is right for you.
Ninety items feels very long. Isn't there a shorter version?
Shorter versions of this scale with fewer items have also been developed and are preferred in some situations. However, because the long form shows symptoms through a more detailed subscale profile, it is often used in an initial assessment. If you get tired while filling it in, there is nothing wrong with taking a short break.
Can I see my results and have a copy?
The assessment concerns you, and you have the right to know your results. You can ask for your results to be discussed with you in clear language. Rather than a raw list of scores, it is often more useful to receive an explanation of what these scores mean.
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Eda Erkan Alapala
Klinik Psikolog. İstanbul Kent Üniversitesi Klinik Psikoloji Tezli Yüksek Lisans mezunu; bilişsel davranışçı terapi, çocuk merkezli oyun terapisi ve çocuk-ergen psikoterapisi alanlarında eğitimlerini tamamlamıştır.
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