Dear Doctor: Can marijuana use really increase the risk of high blood pressure, as a recent study suggests? I thought marijuana was supposed to make you relax.

Dear Reader: If you'll recall, there was a time when smoking tobacco was similarly touted as a healthy way to relax. Only after years of study and national educational campaigns did the public began to realize the detriments of tobacco. Today, in the desire to legalize marijuana, proponents have focused on its potential health benefits. That doesn't mean it has no negative effects.

In fact, smoking marijuana leads to an increase in heart rate, increased contraction of the heart and a small increase in blood pressure. The 2017 European Journal of Preventive Cardiology study you mentioned attempted to quantify these negative effects.

The data used in the study come from a national survey in 2005 in which people over the age of 20 were asked: "Have you ever used marijuana or hashish?" Participants who answered "yes" were termed "marijuana users." The authors also asked the year that people first used marijuana, from which they calculated total years of use. The authors then looked at mortality data from 1991 to 2011.

In this study, 56.5 percent of the 1,213 eligible participants were qualified as marijuana users. Note that 63 percent of these "users" also had a history of smoking tobacco. The overall death rate of marijuana users was 29.7 percent, while in non-users the rate was 26.2 percent. The authors found that the death rate from high blood pressure was 4.3 percent higher in the users of marijuana, but they didn't find a difference in death rates from heart attacks or strokes.

But let's look at the major problems with this study. First, the definition of "marijuana user" was problematic. People who used marijuana once in their lifetime were quantified as marijuana users. The data didn't differentiate between someone who had used marijuana every day for the last 20 years and someone who used it once in college. Next, the number of participants was relatively small, which affects the conclusiveness of the findings. For example, in this study, cigarette smokers had less risk of dying from a heart attack than did non-smokers. That runs counter to large trials showing the opposite. Lastly, many of the marijuana smokers also smoked cigarettes -- so if the data about cigarette smokers were inaccurate, as the suspect finding suggests, there may be further inaccuracies in the data.

However, the study does highlight that marijuana users had a higher rate of high blood pressure. This was also found in a 2016 study showing a mild elevation of blood pressure in marijuana users. Among people who used marijuana one to six days per month, the systolic blood pressure was elevated by 1.3 points on average, and among those who used 21 to 30 days per month, the systolic blood pressure was elevated by 2.6 points on average.

All these data point to how poorly we understand the health consequences of marijuana use. For example, we simply don't know whether marijuana smoking has the same negative vascular effects as tobacco smoking. With less fear of incarceration over marijuana use, perhaps more people will participate in larger studies to assess marijuana's effect upon the cardiovascular system.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: My husband was in the hospital recently, and at night he would get quite agitated. He yelled, took off his clothes and tried to pull out his IV. He had to be secured to his bed to keep him from leaving. But in the morning, he'd be fine and couldn't remember anything from the night before. What's happening? How can I help?

Dear Reader: What you've described is a few of a group of behaviors commonly known as sundowning, or sundowner, syndrome. It's a descriptive term, not a psychiatric diagnosis. However, it's broadly recognized as anxiety, confusion or agitation that is triggered by the onset of waning daylight. Sundowning can begin anywhere from late afternoon to late evening, and usually resolves in the morning, with the return of daylight.

In addition to the symptoms that you mentioned, people may have mood swings, become demanding, suspicious or even paranoid, hallucinate, hear voices, pace or become unaware of time and place. While sundowning is most commonly observed in people with dementia, impaired cognition and Alzheimer's disease, it can also affect individuals who are institutionalized.

Exactly what causes these behaviors to develop isn't yet known. However, in addition to the low light and emerging shadows that give the syndrome its name, triggers can include fatigue, sleeplessness, lack of mental stimulation, disrupted circadian rhythms and the presence of an infection, such as a urinary tract infection.

To see your loved one vanish into the throes of sundowning is upsetting and painful. But once an episode has begun, neither logic nor coaxing can help. Don't try to talk or reason the person out of their fears. If they are hallucinating, don't try to bring them into the present. The best thing you can do is stay calm and be reassuring.

Over the long term, approaches to managing this behavior include:

-- Set up a daily routine with consistent waking and bed times, and regular mealtimes. This will form a predictable framework that can help the individual feel safe.

-- Schedule any taxing activities for early in the day, when the person is at their best. Try not to do more than one or two significant activities, like a doctor's appointment, a shopping trip, or visits from friends or relatives, per day.

-- Watch the diet for any possible triggers. If it turns out that caffeine and sugar cause problems, consider eliminating them, or limit them to earlier in the day.

-- As daylight fades, turn on lots of lights and close the curtains. Limiting noise can also be helpful.

-- Check with your family doctor to see whether a supplement like melatonin may help with sleep cycles.

We are keenly aware of the mental and emotional challenges of being the caregiver at a time like this. That's why we think it's so important that you take time -- make the time -- to care for yourself as well. Take regular breaks, enlist outside help and see a counselor to help process what you're going through. It will bolster your own health and will help you to be an even more effective caregiver.

And if any of you readers have successful strategies we haven't mentioned that you'd like to share, we'd love to hear from you.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Could you explain panic attacks? I never knew what people were talking about until a few months ago, while sitting at the computer. I felt as if I had stopped breathing; I thought I was dying. I ended up in the ER, but no problems were found. This has happened several times since, and I want my life back.

Dear Reader: Panic attacks are truly a scary experience, especially if you've never had them before. Many of the symptoms are similar to those of a heart attack, causing people to seek immediate attention in an urgent care department or emergency room. The symptoms, which develop suddenly, can include chest pain, heart palpitations, sweating, nausea, shortness of breath, lightheadedness and, for many, the feeling that they're going to die.

Such attacks are surprisingly common. One-third of people have at least one panic attack during their lifetime. Those who experience recurrent panic attacks not related to generalized anxiety, depression, obsessive-compulsive disorder or post-traumatic stress disorder have what is termed panic disorder. People with panic disorder have a persistent worry about having another panic attack and the consequences of future attacks. That leads them to avoid situations that may induce panic attacks, which, in turn, leads to a profound alteration in quality of life. Panic disorder affects nearly 3 percent of the population, ages 15 to 54.

People with panic disorder often report an increase in stressful life events over the past year and, even more often, within the past month. Genetic factors also play a role. A person who has a first-degree family member with panic disorder is three times more likely to develop the disorder compared to people without such a tie. Further, an identical twin is five times more likely to have anxiety and panic if his or her twin has the disorder.

The symptoms of panic attacks are essentially a normal "fight or flight" response to a very stressful situation, such as an encounter with a lion, tiger or grizzly bear. However, panic attacks occur without the lion, tiger or bear. Some experts hypothesize that panic attacks are abnormal central nervous system responses to even the most mundane stimuli. Such responses arise in the brain's limbic system, which normally processes sensory information into emotional responses, behavior and memory. The hyperresponsiveness to sensory inputs -- and even the inputs from one's own thinking -- leads to a poor regulation of the autonomic nervous system, which controls heart rate, the contraction of the heart, blood pressure, the gastrointestinal system and sweating. MRI studies have confirmed alterations in the limbic system in people with panic disorder.

Panic attacks can also be precipitated by stimulants such as caffeine, cocaine and amphetamine as well as withdrawal from alcohol, opiates or benzodiazepines like Valium, Ativan and Xanax. Although patients sometimes use benzodiazepines to stop a panic attack, these medications can induce rebound panic when the drug is out of the system, making them a poor treatment option.

Cognitive behavioral therapy shows the greatest sustained benefit in stopping panic attacks, because it can alter the underlying brain responses. Selective serotonin reuptake inhibitor medications also can help.

In summary, starting therapy and possibly medication will be the first steps in getting your life back.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)