We recruited the subjects from follow-up psychiatry out-patient so that they could provide information about their tobacco use. The findings of the current study raise concerns about the reliance on the self-report for tobacco use among psychiatric out-patients.
There is a complex and significant correlation between respiratory disorders and psychiatric conditions. An increased prevalence of respiratory disorders has been reported among patients with psychiatric illnesses.[
1–
3] It has been observed that psychiatric symptoms might be the first presenting symptoms for small cell lung cancer.[
4] A higher prevalence of paraneoplastic syndrome in this cancer type and higher metastasis rates to brain might be possible explanations for this association. A high rate of tobacco use has been implicated as a possible contributor to this association.[
10,
11] Cigarette smoking has been postulated to a common underlying factors for both respiratory illness and panic attacks among patients with these co-morbidities.[
19]
However, the physical illness including respiratory illness largely remains undetected and untreated. Alarmingly low rates of 13% (psychiatric inpatients) and 8% (psychiatric outpatients) of physical examination have been reported among psychiatric patients.[
5,
6] Consequently, most of these conditions are likely to get undetected. An out-patient study from India reported the rate of undetected respiratory illness to be 15%, second only to hypertension.[
20]
Similarly, the rates of psychiatric morbidity is high among patients with lung cancer.[
7] Mood and anxiety disorders are also prevalent among both adult and pediatric patients with asthma and severe lung diseases.[
8,
9] Anxiety and depressive symptoms are predictive of poorer asthma management, associated functional impairment, and inferior treatment outcomes among asthma patients.[
21,
22]
The accuracy of self-report of tobacco use was found to be low in the current study when it was cross checked with urinary cotinine levels for both smoking and smokeless forms. Even among those reporting recent use of tobacco products, the FTND scores were not find to be directly correlated with the urinary cotinine levels. In fact, there was a negative correlation between the FTND-smoking scale scores and urine cotinine levels. Both the smoking and smokeless versions of FTND have been shown to be valid and reliable instruments for assessing tobacco dependence.[
15,
16] These findings suggest that psychiatric out-patients tend to under report recent use of tobacco products. Additionally, the severity of tobacco dependence (as estimates by FTND) does not correlate with the amount of tobacco consumed by these individuals.
The issue of reliability of self-report about tobacco use among psychiatric patients has not been studied adequately. Takeuchi
et al. (2010) reported the first study of reliability of self-report of smoking among patients with schizophrenia.[
14] The correlation between the self-reported smoking and breath CO levels was lost with an increase in duration of psychiatric illness. We could not come across any other study on this issue. We made use of urinary cotinine levels as a biomarker for recent tobacco use. Urine cotinine level has been recognized as a useful biomarker of recent tobacco use. Use of urinary cotinine levels (>50 ng/ml) to validate the self-report of tobacco use has been recommended in medical settings.[
23]
Use of tobacco products by psychiatric patients is associated with a poor treatment response and worsening of the long-term course.[
24] Additionally, it exposes these individuals to the harmful effects of tobacco. Tobacco use continues to be the single largest preventable cause of death globally. Tobacco use is a likely contributor to a relatively higher mortality rate seen among patients with psychiatric disorders.[
25] Smoking has also shown to increase the requirement of neuroleptics.[
26]
Co-morbid use of tobacco products by psychiatric patients is likely to get unnoticed if not assessed properly. Mentally ill receive tobacco treatment on only 12% of their visits to a psychiatrist and 38% of their visits to a primary care physician.[
27]
A focus on the presenting axis I psychiatric illness could overshadow the tobacco use problem among these individuals. Use of biomarkers such as urinary cotinine level can help improve the recognition rate of recent tobacco use by these patients. This information would be of help while planning an appropriate management for them.
The current study has certain strengths. We used an objective biomarker in urine cotinine levels to corroborate the self-report. Additionally, we carried out a quantitative analysis of the urine cotinine levels. We analyzed the data using the two extreme cut off values of urinary cotinine levels. This was done keeping in mind use of different threshold for this value across studies.[
17,
18] However, the concordance rates were poor with both these cut-off values.
However, it is a pilot study with a relatively small sample size. Use of the study subjects as self-controls partly takes care of the issue of sample size. A conclusive sample size could not be estimated due to absence of prior work. The current study sample comprised of a heterogeneous group of different psychiatric disorders as we recruited a consecutive sample presenting to the out-patient psychiatry department. The issue needs to be studied among specific psychiatric illness groups. Also the findings need to be replicated in larger samples from different centers and settings. Additionally, we recruited only male subjects in the current study from a follow up out-patient setting. It would be interesting to compare the findings from female psychiatric patients.
