NOVEL THERAPY: Marijuana could help cure depression

The flower child had it right. Marijuana chills — and doctors are doffing their caps to the once dreaded weed. In fact, many believe that the next big drug for treating depression may come from marijuana.

Depression can kill — and scientists are looking at new ways of handling a disorder that is known to afflict the body and mind alike. The World Health Organisation believes that depression will be the most widespread cause of disability, overtaking cardiovascular illnesses, by 2020. Globally, 20-50 per cent of patients who visit a primary care facility suffer from depression, alone or together with other diseases.

In India, too, depression is widespread. About 15 per cent of Indian men and 20 per cent of women suffer from the disorder, says Sanjay Pattnayak, a clinical psychiatrist at the Vidyasagar Institute of Mental Health and Neurosciences in New Delhi.

Not surprisingly, researchers have been delving deep into the disorder. A team in the US and Italy recently found how certain chemicals activated in the brain in response to mild doses of marijuana actually had an antidepressant effect. Armed with this knowledge, scientists from the University of California, Irvine, and Italy’s Parma University have designed a synthetic molecule that mimics the brain reaction that marijuana sets off.

“Marijuana itself may not have any clinical use for depression. But drugs designed to amplify the actions of marijuana-like neurotransmitters — chemicals that brain cells use to communicate — are showing great promise,” says University of California brain scientist Daniele Piomelli, who led the research.

University of Manchester psychologist Roland Zahn has done brain mapping studies to support his theory that altering a patient’s idea of social values may heal depression. People in whom guilt or other negative feelings are experienced in an “under-differentiated” fashion will be more prone to be depressed, says Zahn.

There are a number of triggers that can lead to depression. It could be genetic, environmental — such as job loss, death of a close person, or lifestyle — or battling a critical illness or stress.

“Once a person has a bout of depression, chances that he or she will have it for the second time go up from 15 per cent to 50 per cent if not treated properly at the first instance. The odds further go up to 75 to 90 per cent on successive occasions,” warns Pattnayak.

He cites the case of 22-year-old Veena Bhatt (name changed), a Delhi-based MBA student. Suffering from recurrent bouts of depression, Veena, who is currently under his treatment, has serious suicidal tendencies.

Depression can be as disabling as a heart attack and arthritis, says the Society for Neuroscience, the world’s largest body of brain scientists, based in Washington DC. “Depressed individuals are 18 times more likely to attempt suicide than people with no mental illness,” it says.

The complexity of the disease which manifests itself in feelings of intense sadness, worthlessness, pessimism and reduced emotional well being stems from the fact that a number of brain areas are affected in the disease. Some of the physical symptoms commonly associated with depression are disturbed sleep and failing sex drive, energy levels, appetite and digestion.

But things have improved since the first set of antidepressant drugs hit the market 50 years ago. “This was made possible by subsequent advances in molecular biology and molecular pharmacology as well as the state-of-the-art tools available for brain imaging in the recent past,” says Sanjeev Jain of the National Institute for Mental Health and Neurosciences (Nimhans), Bangalore. Today, several generations of antidepressant drugs are available, the latest being selective serotonin reuptake inhibitors (SSRIs) such as prozac.

Treating depression with first generation drugs such as tricyclic antidepressants in the initial years of clinical intervention was considered nothing more than taking a blind shot at the disease. Today, doctors have a better understanding about “how” the disease affects a person, particularly about the chemical changes that it brings about in the brain. But “why” the disease occurs is still a puzzle, observes Jain.

Brain scientists studying depression have found altered activity in several parts of the brain, but have not yet been able to pin down the cause of depression to a single specific flaw in any part of the brain. “The complexity of the disease arises from the fact that it affects one or more brain parts,” says Jain. Taking images of a functioning brain has helped scientists get a clearer picture of how a person’s moods, thoughts, appetite and sex drive fail to function and how critical neurotransmitters become out of sync.

Medical scientists now know that depressive illnesses are disorders of the brain caused by a variety of factors. As a result, a “one-size-fits-all” treatment does not work in depression. “Meditation works as much as medication in some cases,” says Alok Sarin, a clinical psychiatrist at the Sitaram Bhartiya Institute of Science & Research in New Delhi.

But only 80 per cent of the patients respond to drugs. That is why scientists have been looking for novel therapies. One such therapy recently approved by the US Food and Drugs Administration is repetitive Transcranial Magnetic Stimulation, or rTMS.

rTMS is a non-invasive method of exciting neurons in the brain by weak pulses of electric currents produced by rapidly altering magnetic fields.

Delhi psychiatrist Sanjay Chugh who has been using rTMS for about a year talks of a patient who benefited from this therapy. Kalpana had been suffering from depression for the last 20 years. After trying several treatments, she opted for rTMS. Six months and 12 sessions later, Kalpana, who had attempted suicide six times before, is feeling a lot better. “It was as if the sun had started to peep out from behind some dark and dense clouds,” she says.

Studies have shown that listening to music with or without antidepressant drugs, too, help patients. “Music does wonders when it comes to treating mild to moderate depression. However, in severely depressed people, music alone will not work,” says Nimhans psychiatrist Manjula Devi, who works very closely with singer Bhimsen Joshi in exploring music’s therapeutic value.

In major depression cases, music can only be an addition to antidepressant drugs, she says. She talks of a woman of 40, suffering from a moderate bout of depression, who got cured simply by instrumental music.

Researchers at the University College of London have come out with a universal test that predicts the risk of someone succumbing to major depression. Developed by Michael King at the university’s mental health department, the kit — a computer programme — assesses each patient visiting a clinic for 39 risk factors. It has already been found to be effective across Europe and some Latin American countries. British scientists are planning to test its effectiveness in Asians too when they embark soon on a clinical trial in China.

With more and more such studies coming in, experts hope that WHO’s dire prognosis may well be stemmed. Depression, they say, can be cured — with or without a reefer.