title: Inverted U shaped effect of nicotine on the severity of depressive symptoms: A population-based survey.
abstract: OBJECTIVE
  To investigate whether that nicotine concentration represented by the degree of smoking dependence variably influence the rate and severity of depressive symptoms.
  
  
  METHODS
  Cross-sectional, analytical study, involving 300 medical students selected by random sampling techniques were asked to complete a questionnaire contains three parts: demographic information, Beck Depression Inventory with cutoff point for depression is 17 and the Fagerström Test for Nicotine dependence with cutoff point for severe dependence is five.
  
  
  RESULTS
  A total of 233 medical students completed the questionnaire; their mean age was (21.38 ± 1.74). The rate of smoking was 22.7% while that of depression was 32.2%. Low dependent smokers in contrast to other groups of smokers and non-smokers display the lowest rate of depressive symptoms (15%), while the highest rate recorded among severely dependent smokers (71.4%, p = 0.0001). After adjustment of other risk factors, regression analysis reveal that severe dependent smokers associated with 12.5 odds of depressive symptoms than non-smokers (p = 0.0001, C.I. 4.10-38.29).
  
  
  CONCLUSIONS
  In comparison with light and moderate smokers, heavy smokers demonstrate higher risk of depressive symptoms in medical students.
authors.affiliation: Department of Pharmacology, College of Medicine, University of Al-Mustansiriyah, Baghdad 14132, Iraq.
authors.forename: Ammar W
authors.initials: AW
authors.lastname: Ashor
keywords: Beck Depression Inventory; Iraq; Medical students; Nicotine dependence; Tobacco smoking
references.citation: Neurosci Biobehav Rev. 2012 Jan;36(1):271-84
references.pmid: 21723317
references.citation: Trends Pharmacol Sci. 2003 Sep;24(9):493-9
references.pmid: 12967775
references.citation: Addict Behav. 2009 Feb;34(2):197-203
references.pmid: 18976867
references.citation: Am J Addict. 2005 Mar-Apr;14(2):106-23
references.pmid: 16019961
references.citation: N Engl J Med. 2010 Jun 17;362(24):2295-303
references.pmid: 20554984
references.citation: Br J Psychiatry. 2010 Jun;196(6):440-6
references.pmid: 20513853
references.citation: J Bras Pneumol. 2009 Jan;35(1):73-82
references.pmid: 19219334
references.citation: Arch Gen Psychiatry. 2004 Nov;61(11):1107-15
references.pmid: 15520358
references.citation: Psychopharmacology (Berl). 2010 Jul;210(4):453-69
references.pmid: 20414766
references.citation: Neurosci Biobehav Rev. 2010 Mar;34(3):295-342
references.pmid: 19665479
references.citation: Arch Gen Psychiatry. 2011 Aug;68(8):817-26
references.pmid: 21810646
references.citation: Nat Rev Neurosci. 2004 Jan;5(1):55-65
references.pmid: 14708004
references.citation: J Psychopharmacol. 2011 Aug;25(8):1134-41
references.pmid: 21169388
references.citation: Nicotine Tob Res. 2011 Mar;13(3):209-14
references.pmid: 21330275
references.citation: Biol Psychol. 2011 Sep;88(1):1-12
references.pmid: 21741435
references.citation: Scand J Public Health. 2009 Jan;37(1):28-34
references.pmid: 19141552
references.citation: Pharmacol Biochem Behav. 2001 Dec;70(4):561-70
references.pmid: 11796154
references.citation: Harv Rev Psychiatry. 2000 Sep;8(3):99-110
references.pmid: 10973935
references.citation: J Prev Med Public Health. 2010 May;43(3):193-204
references.pmid: 20534959
references.citation: Am J Psychiatry. 2002 Jun;159(6):947-53
references.pmid: 12042182
references.citation: Int Rev Psychiatry. 2003 Feb-May;15(1-2):50-6
references.pmid: 12745310
references.citation: Psychopharmacology (Berl). 2006 Mar;184(3-4):567-76
references.pmid: 16463194