Heat Stress in Individuals With Schizophrenia
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-85
SponsorUniversity of Ottawa
About this trial
Schizophrenia is a severe mental illness affecting approximately 24 million people worldwide and is associated with more than double the all cause mortality risk of the general population. Emerging evidence demonstrates that elevated temperatures acutely worsen mental health symptoms and significantly increase the risk of heat related morbidity and mortality. For people living with schizophrenia, prolonged exposure to heat can exacerbate psychiatric symptoms, impair judgment and decision making, and reduce the ability to engage in protective behaviors such as increasing hydration, reducing clothing, improving ventilation, or seeking cooler environments. As a result, individuals with schizophrenia may experience higher rates of heat related illness. To date our understanding of heat exposure effects in individuals with schizophrenia remains incomplete, hindering the development of evidence-based strategies to protect them.
Thus, the primary objective of this exploratory study is to gather preliminary data on the effects of indoor overheating on physiological responses (core body temperature and cardiovascular function), cognitive performance (attention, working memory, and reaction time), and mood in adults with schizophrenia. Specifically, we will assess whether maintaining indoor conditions at the upper recommended temperature limit for older adults (26°C, 45% relative humidity \[RH\]; PMID: 38329752) is sufficient to mitigate physiological strain compared with exposure to a hot indoor environment (36°C, 45% RH) representative of non-air-conditioned homes during extreme heat events in individuals with schizophrenia. In both conditions, the individual will remain seated at rest while wearing light clothing (t shirt and shorts), with the exception of performing 15 minutes of stepping exercise (4-4.5 METS) each hour (excluding the lunch period) to reflect typical daily activities of daily living.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
English or French speaking.
Ability to provide informed consent.
Individuals with and without schizophrenia or schizoaffective disorder.
Disqualifiers
Endurance exercise training (greater than 3 sessions of vigorous exercise training per week for 30 minutes or more)
Restrictions to physical activity
Any history of diagnoses for other psychiatric disorders deemed to make participation in the study inadvisable.
Trial design
Design model
Crossover
Treatments tested in this trial
Simulated exposure to indoor overheating
Other interventionIndividuals with schizophrenia exposed to a 6-hour simulated heat exposure
Treatment groups
10 Participants
are divided into 2 treatment groupsGroup A: Exposure to indoor temperature upper limit of 26°CExperimental treatment 1 intervention
Group B: Exposure to hot indoor environment of 36°CExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Core temperature (Peak) during daylong exposure to indoor overheating
Peak core (indexed by visceral temperature) temperature (15 min average) during exposure. Visceral temperature is measured continuously throughout the 6 hour exposure to the simulated indoor overheating.
Time frame
End of 6 hour daylong exposureSecondary outcomes
1
Profiles of Mood States (POMS) during daylong exposure to indoor overheating
Potential changes in mood (7 subscales of mood: tension, anger, depression, fatigue, confusion, vigor and esteem related affect). The POMS-40 is a validated, self-administered questionnaire that examines seven distinct aspects of mood state across two positive subscales (Esteem-Related Affect, and Vigor) and five negative subscales (Fatigue, Tension, Confusion, Anger, and Depression), which are described across 40 distinct adjectives. For each individual item, participants are asked to describe "how you feel right now" by responding using a 5-point Likert scale (0 = "Not at all", 1 = "A little", 2 = "Moderately", 3 = "Quite a lot", or 4 = "Extremely"). The values of items associated with a specific subscale (e.g., Fatigue) are summed to calculate its score.
Time frame
At the start (hour 0) and end of 6 hour daylong exposure2
Environmental Symptoms Questionnaire (ESQ) during daylong exposure to indoor overheating
Self-reported environmental reactions and medical symptomatology associated with prolonged heat exposure. The ESQ-IV is a validated 68-item, self-administered questionnaire that has been used successfully in identifying symptomatology during exposure to a wide variety of environmental conditions, including heat exposure. Participants are asked to assess and described "how you have been feeling today" by responding to each item using a 6-point Likert scale (0 = "Not at all", 1 = "Slight", 2 = "Somewhat", 3 = "Moderate", 4 = "Quite a bit", or 5 = "Extreme"). Total Symptom Score is calculated from this data by taking the sum of the intensity ratings from all 68 individual items using reverse scores for the three positive items from the list ("I Felt Good", "I Felt Alert", and "I Felt Wide Awake").
Time frame
At the start (hour 0) and end of 6 hour daylong exposure3
Perceived exertion scale during daylong exposure to indoor temperature limit.
Perceived exertional assessed via an ordinal scale ("How hard are you working?") ranging from "no exertional at all" to "maximal exertion"
Time frame
At the start (hour 0) and end of 6 hour daylong exposure4
Activity levels (total steps taken) during daylong exposure to indoor overheating
Activity levels, quantified by number of steps taken per hour and totaled for each 6 hour exposure, assessed via a wearable accelerometer worn on the wrist and hip.
Time frame
End of 6 hour daylong exposureSponsors and contacts
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Source ClinicalTrials.gov