People trying to quit smoking these days need much more intensive and individualized treatment, as they are more highly addicted to nicotine than two decades ago, US researchers said Tuesday at the annual meeting of American College of Chest Physicians.

Lead author Dr. David P Sachs from the Palo Alto Center for Pulmonary Disease Prevention in California, and other colleagues from the Palo Alto Center and also the St Helena Hospital in Napa, California found that the severity of nicotine dependence has gone up 12 percent between 1989 and 2006 while the percentage of people classed as highly nicotine dependent had gone up by 32 percent.

For the study, the researchers analyzed the pre-treatment severity of nicotine dependence of participants in three studies carried out between 1989 and 2006. The studies were as follows: 1. Nicotine Patch Study (NPS) with 220 participants enrolled from Dec 89 to April 90; 2. Bupropion SR Study (BSRS) with 206 participants enrolled from Sep 94 to Dec 94; 3. St. Helena Hospital Center for a Smoke-Free Life (CSFL) with 206 participants enrolled from Feb 05 to Oct 06.

Nicotine dependence was measured by using the Fagerström Tolerance Questionnaire, which is scored on a scale of 0 (no dependence) to 11 (worst dependence) or the easier-to-use Fagerström Test for Nicotine Dependence (a 10-point scale). Scores of at least 7 designate severe dependence. While nicotine dependence was 6.65 in 1989, it increased to 7.0 in 1994 and 7.44 in 2006. Overall, the proportion of people who were highly nicotine-dependent rose from 55.5 percent to 73 percent over the study period.

The researchers couldn’t give a specific reason for why the nicotine dependence has risen so much in the last 15 years. Dr. Sachs said “individuals who have less severe nicotine dependence have already been successful at quitting smoking, which leaves a larger percentage of patients who are highly nicotine dependent among the greater tobacco-using community.”

Dr. Sachs concluded that “people who are highly nicotine dependent need much more intensive and individualized treatment to make certain that nicotine withdrawal symptoms are suppressed and stay suppressed.” Moreover, the more severity nicotine dependent a person is, the greater the medical need for more intensive tobacco- dependent therapies.

According to the US Centers for Disease Control and Prevention, an estimated 21 percent of US adults – 45 million people – are smoking, including 24 percent of men and 18 percent of women. People can easily find out whether they are highly nicotine dependent with a quick “bedside” test. If you light up the first cigarette within the first 30 minutes of awakening then you’re most likely highly nicotine dependent, Dr. Sachs said.

According to current estimates, smoking appears to be the biggest cause of preventable deaths in the US, killing more than 400,000 people each year. Also, secondhand smoking seems to be higher than previously believed, killing almost 40,000 people annually because of cancers, respiratory infections and asthma, conditions also diagnosed in the case of smokers.