In the new film “Cake,” Jennifer Aniston plays a woman with chronic pain, a condition that is often accompanied by depression. (AP)

Chronic pain affects more people than cancer, diabetes, heart attack and stroke combined. The Institute of Medicine estimates there are more than 100 million sufferers in the United States, costing the nation as much as $635 billion a year in medical treatment and lost productivity.

It’s even the focus of a new movie: “Cake,” starring Jennifer Anniston as a woman struggling with chronic pain, is scheduled for release Jan. 23.

Chronic pain can be devastating, and a challenge to treat. As a mental health counselor, I have seen it damage productive lives and tear families apart.

Pain sufferers often are misdiagnosed, misunderstood and miserable. Their friends and family can become worn out from listening to complaints. Their identities may be significantly altered because they cannot engage in activities they once enjoyed. Doctors get frustrated by the inability to provide a cure.

I have worked with people who had full, rich lives as corporate leaders, mothers, athletes and professors before their chronic pain. However, by the time I saw them they were isolated, overmedicated and depressed, and they believed their life was devoid of meaning.

The good news is that chronic pain is treatable with the right blend of approaches. The traditional healing model — take medications, rest, get better — doesn’t work with this illness. But there are ways to reduce pain and rebuild yourself.

I worked with one client who lived with chronic pain for more than 15 years. He was a pilot before his illness. When I met him, he was taking copious amounts of pain medications, but all were useless. The drugs simply made his pain worse while clouding both his mind and mood.

He lived in his easy chair in front of the television. He watched the clock, praying for relief and waiting for his next dose. His three adult children never visited because they were tired of his constant irritability and complaining. When I asked about his goals, he said, “I want to mow my lawn again,” with tears in his eyes. After eight months of physical therapy, counseling and weaning off addictive medications, he was able to achieve this everyday task and much more.

Usually, people feel acute pain after an illness or injury. If pain lasts beyond the time it takes to heal, or longer than 12 weeks, it’s considered chronic. Michael Clark, a psychiatrist and director of the pain treatment program at Johns Hopkins Hospital, explains the underlying neurobiology: “The disease of chronic pain is more than just acute pain that lasts longer. It has greater intensity, causes impaired function and can migrate beyond the original pain site. The nervous system becomes distorted. Pain receptors get amplified and internal pain blockers minimized, which can make even the lightest touch be perceived as painful.”

Individuals may work with many medical specialists to find help even as relief remains elusive because they focus only on the pain symptoms.

“Chronic pain is not simply a single symptom or a straightforward experience like acute pain,” Clark says.

Chronic pain frequently is accompanied by depression, which can include fatigue, anxiety and changes in mood, appetite and sleep. Sufferers have some of the lowest reported quality-of-life levels among people with major illnesses. Pain combined with depression can hold sufferers back from engaging in life, which may lead to damaged relationships and loss of employment.

“In my practice, I routinely see clients who have suffered from chronic pain for many years. This can result in isolating behavior — especially toward spouses and immediate family members,” says Melissa Delgado, a gynecologist and obstetrician in Vienna, Va., who specializes in treating women with chronic pelvic pain.

“Approximately one-third to three-quarters of people with chronic pain experience moderate to severe depression,” Clark says. “Patients with depression experience increased pain because of overlap in the two affected systems: pain reception and mood regulation. Both depression and chronic pain share some of the same neurotransmitters and nerve pathways. So pain is worse, function is poor, response to pain treatment is diminished and their prognosis is worse until they can get their depression under better control.”

Antidepressant medication can provide considerable relief for some. I have seen amazing improvements in clients who focus on treating their depression in addition to pain reduction.

One woman wanted to have her legs amputated because of the interminable, horrific pain, but once her depression was properly managed, her pain diminished. She wasn’t 100 percent pain-free, but it was manageable. I remember her overwhelming joy when she went with her husband to a concert for the first time since the onset of pain more than six years before. They danced in the aisles.

Another well-understood contributor to chronic pain is the extended use of strong, addictive medications such as opioids and benzodiazepines such as Percocet and Valium. If they are taken over many years, they can make pain significantly worse.

These medications block the transmission of pain from the site to the brain, so over time nerves send stronger pain signals. It’s as though the nerves turn up the volume to help the brain hear the pain. Higher doses of medication are required to block the louder signals. Pain receptors and processors get so distorted that eventually most stimuli are perceived as pain and these medications no longer work. Additionally, these drugs blur thinking, depress mood and encourage isolating behavior.

“Physicians should take a holistic approach and not just focus on individual symptoms,” Delgado says. “Chronic pain is a complex and debilitating disease, and as a result, we need the multidisciplinary approach to address the whole person.” Medical doctors, counselors and physical therapists all add valuable pieces to solving the chronic pain puzzle.

An experienced chronic pain doctor can safely transition someone off addictive and ineffective medications and onto useful pharmaceutical combinations. Physical therapy is also needed, to reactivate injured bodies and reset a hyper-excited nervous system. Careful exercise will teach damaged nerves the difference between normal and harmful sensations. Counseling helps a person find strengths, adjust expectations, manage anxiety, rebuild identity, practice relaxation techniques and repair relationships.

My pilot client, who was grateful to be able to take care of his lawn again, labored through each of these challenging tasks over approximately eight months. Today, he continues to work with a counselor, physical therapist and support group.

The National Institutes of Health has found that individuals who take proactive steps toward managing their pain often find relief regardless of the underlying cause. Helpful actions include engaging in problem-solving, avoiding isolating behaviors, improving communication, embracing physical therapy and working with a counselor to help reframe an illness.

Chronic pain sufferers also need to incorporate structure, activities, socialization, purpose and meaning into each day of their lives. Research studies show that involvement in a meaningful activity or organization greatly improves well-being and happiness.

Benner is a mental health counselor in Bethesda.