1. The PTSD Symptom Scale – Interview (PSS-I)
Jennifer A. Schneider, Ph.D.
National Center for Posttraumatic Stress Disorder,
Department of Veterans Affairs,
Pacific Islands Health Care System,
Spark M. Matsunaga Medical Center,
Honolulu, HI, USA

2. Objectives
Participants will demonstrate knowledge of the research basis for the PSSI
Participants will have an understanding of PSSI structure, administration, and scoring
Participants will be able to utilize the PSSI for clinical or research purposes

3. What is the PSS-I? Semi-structured clinical interview used to:
Diagnose PTSD
Determine PTSD symptom severity

4. Development of the PSS-I
Established Internal Consistency, Reliability, Sensitivity
Shown to be reliable and valid in civilians
Overall, performs as well as the CAPS in diagnosis of PTSD
Research suggests that it has greater sensitivity to PTSD, whereas the CAPS has greater specificity
(Foa et al, 1993; Foa & Tolin, 2000)

5. PSS-I versus CAPS Pros Cons Faster
Greater sensitivity may result in identification of individuals in need of treatment
Cons
Greater sensitivity to PTSD may result in more false positives
Assessment of symptoms in the past 2 weeks, may result in capturing an abnormally asymptomatic or symptomatic window of time that does not reflect the individual’s true functioning
For the PSS-I a score of 1 for an item means that it counts as a symptom – the CAPS requires a 1 for frequency and a 2 for intensity to count an item as a symptom. This means that for the PSS-I it may be easier to get a symptom, thus leading to more “false positives,” or diagnoses of PTSD when the individual does not have PTSD
Because symptoms are assessed in the past 2 weeks, there is the potential for life events to have a significant impact on symptoms that are picked up in the PSSI, just as with other instruments that measure brief windows of symptoms such as the PCL weekly version or the CAPS when the past week is referenced
(Foa et al, 1993; Foa & Tolin, 2000)

6. Structured Clinical Interviews
“Clinical” means that the clinician’s judgment should come into play when making ratings
If the client has a clear response bias, the clinician should adjust ratings accordingly
Utilize observations of the client’s presentation during the assessment in scoring
If the client has a clear response bias, the clinician should adjust ratings accordingly
For example, if in your clinical judgment you believe the person is minimizing, bump your scores up
If you believe the person is exaggerating, bump your scores down – you might do this when you have someone who repeatedly responds with the same high endorsement for each item (every symptom happens “all the time” and is at a 10/10 of distress)
The clinician should utilize information from the assessment itself in scoring
e.g., If the client has difficulty concentrating during the assessment, this should be reflected in ratings for symptom D3

7. DSM-IV-TR Criteria for PTSD
Criterion A: Stressor
The person has been exposed to a traumatic event in which both of the following were present:
The person experienced, witnessed, or was confronted with an event or events that involved actual or threatened death or serious injury, or a threat to the physical integrity of oneself or others
The person's response involved intense fear, helplessness, or horror. Note: in children, this may be expressed instead by disorganized or agitated behavior.
Criterion B: Intrusive Recollections
The traumatic event is persistently reexperienced in one (or more) of the following ways:
Recurrent and intrusive distressing recollections of the event, including images, thoughts, or perceptions. Note: in young children, repetitive play may occur in which themes or aspects of the trauma are expressed.
Recurrent distressing dreams of the event. Note: in children, there may be frightening dreams without recognizable content
Acting or feeling as if the traumatic event were recurring (includes a sense of reliving the experience, illusions, hallucinations, and dissociative flashback episodes, including those that occur upon awakening or when intoxicated). Note: in young children, trauma-specific reenactment may occur.
Intense psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event.
Physiologic reactivity on exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event
(American Psychiatric Association, 2000)
The PSSI essentially goes through most aspects of the DSM-IV-TR criteria for PTSD so it is crucial to familiarize yourselves with these criteria prior to doing this assessment
Criterion B
Intrusive Thoughts: Memories of the event that pop into one’s head out of the blue, untriggered, while awake
Nightmares: May include times when the individual doesn’t recall the nightmare, but wakes up feeling scared, helpless, etc and associates this with the event
Flashbacks: Must involve a sense of walking through the event step-by step, but there is a range to how realistic they are
Triggers – Emotional Distress: Must follow this pattern stimuli -> remembering the event -> emotional distress
Triggers – Physiological Reactivity: Must follow this pattern stimuli -> remembering the event -> physiological reactivity (increased heart rate, increased respiratory rate, tenseness, sweating, etc.)

8. DSM-IV-TR Criteria for PTSD
Criterion C: Avoidance/Numbing
Persistent avoidance of stimuli associated with the trauma and numbing of general responsiveness (not present before the trauma), as indicated by three (or more) of the following:
Efforts to avoid thoughts, feelings, or conversations associated with the trauma
Efforts to avoid activities, places, or people that arouse recollections of the trauma
Inability to recall an important aspect of the trauma
Markedly diminished interest or participation in significant activities
Feeling of detachment or estrangement from others
Restricted range of affect (e.g., unable to have loving feelings)
Sense of foreshortened future (e.g., does not expect to have a career, marriage, children, or a normal life span)
Criterion D: Hyperarousal
Persistent symptoms of increased arousal (not present before the trauma), indicated by two (or more) of the following:
Difficulty falling or staying asleep
Irritability or outbursts of anger
Difficulty concentrating
Hypervigilance
Exaggerated startle response
(American Psychiatric Association, 2000)
Criterion C
Avoiding Thoughts,feelings,conversations: Pushing thoughts, feelings, and conversations about the event away after they have already come up
Avoiding people places and situations: Making the decision not to go to a certain place, see someone, or do something so as not to be reminded of the event
Inability to recall an important aspect: Gaps in memory, fuzziness, uncertainty about the sequence, missing names or faces
Anhedonia: NOT including realistic loss of interest, for example “I don’t surf anymore, but it’s because my leg is broken”
Feeling of detachment: May include actively pushing others away, maintaining a wall between oneself and others, feeling like you’re in a room full of people but all alone
Emotional Numbing: Not feeling the full range of emotions, for example, “I know I love my kids, but I don’t experience it”
Sense of foreshortened future: Includes a sense that bad things will happen, or that one has been permanently negatively impacted by the event
Criterion D
Sleep Difficulty: Includes sleep problems that arise from nightmares
Irritability/Anger:
Difficulty Concentrating: Losing focus, having to reread things, wandering off in conversations
Hypervigilance: Being on guard and watchful in objectively safe situations, needing to sit with back to the wall or where one can see an exit, etc.
Exaggerated Startle Response: A reflexive response to a surprising stimuli

9. DSM-IV-TR Criteria for PTSD
Criterion E: Duration
Duration of the disturbance (symptoms in criteria B, C, and D) is more than one month.
Criterion F: Functional Significance
The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning
Specify if:
Acute: if duration of symptoms is less than three months
Chronic: if duration of symptoms is three months or more
With Delayed Onset: if Onset of symptoms is at least six months after the stressor
(American Psychiatric Association, 2000)

10. PSS-I Structure PSS-I items correspond to DSM-IV criteria for PTSD
DSM-IV Criterion B
B1. Recurrent and intrusive distressing recollections of the event, including images, thoughts, or perceptions
PSS-I Item
1. Have you had recurrent or intrusive distressing thoughts or recollections about the trauma?

11. PSS-I Structure
Ratings are made on a 4-Point Likert Scale that combines frequency and severity
0 – Not at all
1 – Once per week or less/a little
2 – 2 to 4 times per week/somewhat
or more times per week/very much
Frequency and severity are combined because some items lend themselves better to frequency ratings, while others lend themselves better to intensity ratings

12. PSS-I Structure
Frequency refers to the number of occurrences in the time-frame of reference
Severity refers to the subjective distress reported, the duration of the symptom, and its impact/interference
Frequency
E.g., How many times did you have nightmares in the past two weeks
Severity
E.g., How did you feel when you woke up from the nightmare (terrified, anxious, sweaty), How long did it take you to calm down when you woke up from your nightmare, Were you able to get back to sleep

13. PSS-I Structure Estimated Administration Time
20 – 30 minutes in civilians
20 – 40 minutes in veterans

14. This is an example of what the PSS-I looks like

15. PSS-I Administration

16. PSS-I Administration Identify the Criterion A
Typically this is the event which is most distressing at present, however, any traumatic event may be chosen
Establish the presence of Criterion A2
Fear, helplessness, or horror occurring during or after the traumatic event
Establish a Time Frame
Validated for last month & last two weeks
Longer or shorter time frames may be used
Criterion A2
Often people will say that they were “in shock” during the event and felt nothing, or in veterans you may here that their training kicked in and they snapped into action, perhaps only feeling anger
Establish a Time Frame
Validated for last month & last two weeks, but in theory may also be utilized for a longer or shorter time frame
In addition, may be used to obtain a lifetime diagnosis (i.e., assessing symptoms present in the past but not currently) – in this case, the interviewer should identify a particular period of time in the person’s history and evaluate the symptoms present at that time related to the Criterion A – Say: “Now I’m going to ask you about trauma related difficulties you may have experienced since the event.”

17. Establishing Criterion A
DSM-IV-TR Criterion A1 & A2 for PTSD
A1: The person experienced, witnessed, or was confronted with an event or events that involved actual or threatened death or serious injury, or a threat to the physical integrity of self or others
A2: The person’s response involved intense fear, helplessness, or horror. Note: in children this may be expressed instead by disorganized or agitated behavior
When assessing Criterion A, make sure to consider both subjective (the person’s reported sense of threat) as well as objective (the threat associated with the event given the objective facts of the situation)
The traumatic event that is objectively the worst may not be the one that is the most distressing to the individual right now – go with the one that the client states is currently the most distressing based on their subjective experience, as long as this also meets the qualifications of a Criterion A event
When there is ongoing trauma (e.g., childhood physical/sexual abuse, combat), ask if there is one particular time it occurred that stands out for them amongst the others, or ask them to choose one time that it occurred which would represent the rest. You can guide them if they have difficulty identifying one particular time – suggest the first time, the last time, etc.

18. Establishing Criterion A
Helpful Questions:
“In this interview, I will be focusing on one traumatic event. Which of the events that you mentioned to me bothers you the most at the present time?”
“Which of the traumatic experiences you mentioned currently gets in the way of your life the most?
“Which one of these events do you find yourself having the most upsetting and unwanted thoughts about lately?”
(Feeny & Foa, 2002)
If the individual is still having difficulty identifying a single criterion A after you’ve asked the above questions, you can also ask which experience is the one that they are least inclined to discuss/most avoidant of

19. Criterion A Examples Directly Experienced Trauma Witnessed Trauma
Combat, life threatening accident (e.g., plane crash, motor vehicle accident), violent physical/sexual assault (in childhood or adulthood), torture, incarceration as a prisoner of war or in a concentration camp, natural or manmade disaster (e.g., earthquake, fire hurricane, flood), robbery, stabbing/shooting, being diagnosed with a life threatening illness
Witnessed Trauma
Observing death or injury of another person due to assault, war, or disaster, unexpectedly seeing a dead body or body parts
Confronted with/learned about Trauma
learning of family member’s (or friend’s) sudden, unexpected death, or learning that one’s child had a life threatening disease
Threats to physical integrity include traumas such as sexual abuse/assault, being taken as a prisoner of war, etc.

20. Introduction
“I want to get a really good picture of how things have been going for you in the past 2 weeks in terms of trauma related difficulties. So, today is (insert date)________, two weeks ago takes us back to (insert date)________, this is the period of time that I will focus on. Remember that throughout the interview I will be asking about difficulties related to the event that you identified as the most distressing, the (repeat event). Do you have any questions?”
(Feeny & Foa, 2002)

21. PSS-I Administration: Rules of Thumb
Read all questions verbatim
Modification of questions is allowed when essential for the person’s understanding
Additional questions are allowed as necessary for clarification
Do not double-code
The same experience as reported by the person should not be used to score more than one item
“If a person reports not going to the gym anymore, this should be rated as either behavioral avoidance (if fear is the motivating factor) or loss of interest (if lack of motivation or energy is the explanation) but not both”

22. PSS-I Administration: Rules of Thumb
Do not use PSS-I anchor points in questions 
Translate them in to your own words
Use all information obtained during the interview when making ratings
Use information from later in the interview to modify earlier ratings
Use observations of the person’s behavior during the assessment
Instead of asking if a particular experience happened “5 or more times per week” ask open-ended questions such as “how often has that happened in the past 2 weeks”
Instead of asking if the experience was “very much” distressing ask “how distressing was that”
Ask Open-Ended Questions – Don’t “lead” the client

23. PSS-I Administration: Rules of Thumb
Make sure that symptoms which are not directly linked to the trauma (e.g. concentration, irritability/anger) represent a change from previous functioning   
Repeatedly reiterate the time-frame within which you are assessing symptoms
Impaired functioning that is not above pre-trauma levels should be scored a 0
Change in functioning can be particularly difficult to determine in cases of childhood trauma because the event(s) occurred so long ago. In the event of this difficulty, ask the person whether he or she perceives the symptom to be related to the trauma and how so. If the symptom does appear to be trauma related, then include it in your ratings

24. PSS-I Item-By-Item Reexperiencing
Have you had recurrent or intrusive distressing thoughts or recollections about the trauma?
Only score if thoughts and images are related to the identified trauma
Frequency estimates are most useful for rating this symptom, however intensity ratings can help in scoring when the frequency rating falls between two scores
Have you been having recurrent bad dreams or nightmares about the trauma?
Only score if nightmares are related to the identified trauma
Frequency estimates are sufficient for rating this symptom, however, intensity may be used to bump up scores if its severity might not otherwise be reflected
Have you had the experience of suddenly reliving the trauma, flashbacks of it, acting or feeling as if it were re-occurring?
Use a combination of frequency and severity to score, gathering frequency information first
Differentiate between the experience “happening again” and having a memory, emotion, or physical feeling related to the trauma (this would be evidence of symptoms in question 4 and/or 5)
Intrusive Thoughts – These are thoughts that pop up completely un-triggered, while the individual is awake
Nightmares: do not have to be exact replays of the trauma, but can include components of it, similar themes, or may just lead the person to wake up with a similar feeling even if they cannot recall the nightmare. If the person reports one really bad night with several terrifying nightmares that woke her up screaming, but reports having no dreams on any other nights, you can take this into consideration in your rating (i.e., increase your rating to account for the severity of the one night).
Flashbacks: This must include an at least momentary sense that the trauma is re-occurring (e.g., “it is happening again” or “I am back in time”. If the person’s description of the event refers to a very distressing sensory or emotional experience that is similar to the feelings experienced during the trauma, and the person does not report true dissociation, score the experience as symptom 4 or 5 below

25. PSS-I Item-By-Item Reexperiencing
Have you been intensely EMOTIONALLY upset when reminded of the trauma (includes anniversary reactions)?
“Emotionally upset” refers to a range of emotions including but not limited to fear, sadness, anger, guilt or shame, and worry.
Elicit examples of trauma reminders or triggers that bring up this distress (e.g., for an assault victim: nighttime, TV shows, newspaper articles, people that look like the assailant, knives, etc)
Do not rate if the distress is appropriate to the situation (e.g. fear when walking down a dark alley in a bad neighborhood)
Intensity ratings should be utilized when the frequency rating is between two scores
Have you been having intense PHYSICAL reactions (e.g., sweaty, heart palpitations) when reminded of the trauma?
Frequency estimates are most useful for rating this symptom – Intensity ratings should be utilized when the frequency rating is between two scores
Consider the list of triggers elicited in question 4 and ask about physical reactions in addition to the emotional distress already queried (e.g., sweating, nausea, heart racing, increased respiratory rate)

26. PSS-I Item-By-Item Avoidance
Have you persistently been making efforts to avoid thoughts or feelings associated with the trauma?
May include “pushing the thoughts away,” talking on the phone, “keeping busy,” playing music, or drug/alcohol use with the specific goal of avoiding or distracting from trauma-related thoughts and feelings
Frequency information is most useful when rating this item. Use distress ratings to push up or down a rating that falls between two scores.
Have you persistently been making efforts to avoid activities, situations, or places that remind you of the trauma?
Only score if the avoidance of people, places, and situations is specifically linked to not wanting to confront the identified criterion A.
Generate a list of situations, people, and places that are avoided and determine how much avoidance of each impairs functioning
Are there any important aspects about the trauma that you still cannot recall?
Score only if there are important/significant gaps or missing details in the trauma and if these clearly are not due to normal aging/memory decay or loss of consciousness during trauma
1 – For example, excessive working might be included here, if the goal is to distract oneself from trauma recollections
3 - For instance, psychogenic amnesia may be scored if the person reports a fairly detailed memory of the trauma up to a certain point, then a gap in time or detail, followed by more details about what happened after that gap.

27. PSS-I Item-By-Item Avoidance
Have you markedly lost interest in free time activities since the trauma?
Do not score if the person reports reduced activity related to avoidance of trauma reminders or to physical inability (e.g., injury, age)
Apathy, low energy/motivation, lack of interest (e.g., “I used to love doing X, but it just isn’t fun anymore”) should be coded here, even if it appears to be related to depression
Have you felt detached or cut off from others around you since the trauma?
For example, feeling cutoff, disconnected, alienated, different, keeping people at arms length, or being unable to feel close to or trust of others
Severity (e.g., “How strong is the feeling of disconnection?” “Do you have any one that you feel close to, even if it’s not all the time?”) is often more useful than frequency for rating this item
Have you felt that your ability to experience the whole range of emotions is impaired (e.g., unable to have loving feelings)?
Emotional numbness refers to emotional flatness or lack of responsivity despite stimuli, restricted range of affect for example feeling sad all the time, having difficulty experiencing love and happiness, or experiencing anger more easily than other emotions.
Severity (i.e., fluctuation versus continuous emotional numbing during the identified time frame) may assist in scoring

28. PSS-I Item-By-Item
Have you felt that any future plans or hopes have changed because of the assault (e.g., no career, marriage, children, or long life)?
Score if the individual reports having been permanently negatively impacted (e.g., “I will never have children”, “never achieve anything I wanted to do”, “my life will be short”, etc.) directly as a result of the traumatic experience
Frequency of thoughts and severity (level of “damage” or permanency of the “damage”) are both useful in scoring

29. PSS-I Item-By-Item Hyperarousal
Have you had persistent difficulty falling or staying asleep?
Combined frequency and intensity ratings are most helpful here (i.e., determine how often the individual is having difficulty falling or staying asleep, and then determine how many hours of sleep were lost)
Get specific when obtaining severity (ask “how long did it take to fall asleep?,” “how many times did you wake up during the night and how long did you stay up for?”)
Sleep disturbance should represent a change in functioning from prior to the trauma
Score based on the information provided by the individual, even if sleep medication is being used (i.e., do not speculate about how the person’s sleep would be without medication)
Use distress ratings to push up or down a rating that falls between two scores
Have you been continuously irritable or have outbursts of anger?
Irritability should represent a change in functioning from prior to the trauma, and if not should be scored 0
Frequency of irritability or anger should be assessed first

30. PSS-I Item-By-Item Hyperarousal
Have you had persistent difficulty concentrating?
Severity estimates are most useful for rating this symptom (e.g., “do you find you have to reread things you’ve just read,” “do you lose track or wander off during conversations,” “are you able to concentrate if there is something very compelling”)
Factor the individual’s ability to attend to the assessment into scoring
Are you overly alert (e.g., check to see who is around you, etc.) since the trauma?
For example, being wary, on guard, scanning or doing perimeter checks, listening for small sounds, sitting with one’s back to the wall, positioning oneself in direct line of sight to an exit, keeping weapons, double checking locks, etc.
Frequency (e.g., the amount of time spent engaging in the aforementioned behaviors) should be determined
Have you been jumpier, more easily startled, since the trauma?
Startle response should be scored only if it is unreasonable based on the stimulus (e.g., it is reasonable to react by jumping or ducking if a car is hurtling towards you)
Determine the frequency if exaggerated startle response and then utilize severity ratings (e.g., the amount of time it takes to calm down after being startled) to bump the score up or down if the rating falls between two scores

31. PSS-I Scoring

32. PSS-I Scoring Severity 0 – 10 Below Threshold
11 – Subclinical – Mild
16 – Mild
21 – Moderate
26 – Moderately Severe
31 – Severe
41 – Extremely Severe

33. PSS-I Scoring Symptoms count as endorsed if they have a rating of:
≥ 1 in civilians
≥ 2 in veterans (unless underreporting is suspected)
PTSD Diagnosis
1 Reexperiencing Symptom
3 Avoidance Symptoms
2 hyperarousal Symptoms
Symptoms must be present for > 1 month

34. Questions??

35. References
American Psychiatric Association: Diagnostic and statistical manual of mental disorders, Fourth Edition, Text Revision. Washington, DC, American Psychiatric Association, 2000.
*Feeny, N.C., & Foa, E.B. (2002). Manual for the Administration and Scoring of the PTSD Symptom Scale – Interview (PSS-I)
*Foa, E., Riggs, D., Dancu, C., & Rothbaum, B.(1993). Reliability and validity of a brief instrument for assessing post-traumatic stress disorder. Journal of Traumatic Stress, 6,
Foa, E & Tolin, DF (2000). Comparison of the PTSD Symptom Scale-Interview Version and the Clinician Administered PTSD Scale. Journal of Traumatic Stress, 13,
* Indicates articles suggested for further reading