Protocol - Multi-dimensional Assessment of Antipsychotic Medication Side Effects

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Glasgow Antipsychotic Side-effect Scale (GASS)


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The Glasgow Antipsychotic Side-effect Scale (GASS) is a 22-item, self-administered checklist that captures a patient’s viewpoint about suffering from excessive side effects from the antipsychotic medication. Questions 1-20 relate to the previous week and questions 21-22 to the last three months. For questions 1-20, "never" = 0 points, "once" = 1 points, "a few times" = 2 points, and "everyday" = 3 points. For questions 21- 22, "yes" = 3 points and "no" = 0 points. All items are added together to give a total score and higher scores reflect more frequent experience of side effects.


Glasgow Antipsychotic Side‐effect Scale (GASS)

Sex:M / F
Please list current medication and total daily doses below:______________________________________

Please list current medication and total daily doses below:

This questionnaire is about how you have been recently. It is being used to determine if you are suffering from excessive side effects from your antipsychotic medication.

Please place a tick in the column which best indicates the degree to which you have experienced the following side effects. Tick the end box if you found that the side effect distressed you.

Over the past week:



A few times


Tick this box if distressing

1. I felt sleepy during the day

2. I felt drugged or like a zombie

3. I felt dizzy when I stood up and/or have fainted

4. I have felt my heart beating irregularly or unusually fast

5. My muscles have been tense or jerky

6. My hands or arms have been shaky

7. My legs have felt restless and/or I couldn’t sit still

8. I have been drooling

9. My movements or walking have been slower than usual

10. I have had, or people have noticed uncontrollable movements of my face or body

11. My vision has been blurry

12. My mouth has been dry

13. I have had difficulty passing urine

14. I have felt like I am going to be sick or have vomited

15. I have wet the bed

16. I have been very thirsty and/or passing urine frequently

17. The areas around my nipples have been sore and swollen

18. I have noticed fluid coming from my nipples

19. I have had problems enjoying sex

20. Men only: I have had problems getting an erection

Tick yes or no for the following questions about the last three months



Tick this box if distressing

21. Women only: I have noticed a change in my periods

22. Men and women: I have been gaining weight

© 2007 Waddell & Taylor


For questions 1-20 award 1 point for the answer "once," 2 points for the answer "a few times," and 3 points for the answer "everyday."

Please note zero points are awarded for an answer of "never."

For questions 21 and 22, award 3 points for a "yes" answer and 0 points for a "no." Total for all questions =

For male and female patients a total score of:
        • 0-12 = absent/mild side effects
        • 13-26 = moderate side effects
        • over 26 = severe side effects

Side effects covered by questions
        • 1-2 sedation and CNS side effects
        • 3-4 cardiovascular side effects
        • 5-10 extra‐pyramidal side effects
        • 11-13 anticholinergic side effects
        • 14 gastro‐intestinal side effects
        • 15 genitourinary side effects
        • 16 screening for diabetes mellitus
        • 17-21 prolactinaemic side effects
        • 22 weight gain

The column relating to the distress experienced with a particular side effect is not scored but is intended to inform the clinician of the service user’s views and condition.

Personnel and Training Required


Equipment Needs



Requirement CategoryRequired
Average time of greater than 15 minutes in an unaffected individualNo
Major equipmentNo
Specialized requirements for biospecimen collectionNo
Specialized trainingNo

Mode of Administration


Life Stage:


Specific Instructions:

The Glasgow Antipsychotic Side-effect Scale (GASS) should be completed in proximity to another mental health professional or person to discuss any questions or issues.

Research Domain Information

Release Date:

January 17, 2017


A questionnaire to assess the suffering side effects from antipsychotic medication


This measure assesses a patient’s wellbeing recently and determine if the patient is suffering from excessive side effects from antipsychotic medication.

Selection Rationale

Glasgow Antipsychotic Side-effect Scale (GASS) is a valid, reliable tool that could aid systematic clinical assessment, particularly in view of its brevity and user-friendly language. GASS is suitable for busy clinical environments and as part of routine clinical monitoring.




Common Data Elements (CDE)Mental Health Antipsychotic Agent Side Effect Assessment Scale5628244CDE Browser

Process and Review

The Expert Review Panel has not reviewed this measure yet.


Waddell, L., & Taylor, M. (2008). A new self-rating scale for detecting atypical or second-generation antipsychotic side effects. Journal of Psychopharmacology, 22(3), 238-243.

General References

Day, J. C., Wood, G., Dewey, M., & Bentall, R. P. (1995). A self-rating scale for measuring neuroleptic side-effects. Validation in a group of schizophrenic patients. British Journal of Psychiatry, 166, 650-653.

Lambert, M., Conus, P., Eide, P., Mass, R., Karow, A., Moritz, S., Golks, D., & Naber, D. (2004). Impact of present and past antipsychotic side effects on attitude toward typical antipsychotic treatment and adherence. European Psychiatry, 19, 415-422.

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