Environmental exposure to natural sour gas containing sulfur compounds results in elevated depression and hopelessness scores

Some parts of Masjid-i-Sulaiman (MIS) (Khozestan provinces, southwest of Iran) are contaminated with subsurface leakage of natural sour gas containing H2S. It is reported that the incidence of suicide by self-burning in MIS is very high. High endogenous H2S levels have been found in the brain and it is involved in the brain functions. Because there is no report about the effect(s) of natural sour gas containing sulfur compounds on the function(s) of human brain, the present study was done. The study was performed on 128 individuals exposed or unexposed to natural sour gas. The exposed group consisted of 64 persons (39 males, 25 females). Unexposed subjects were matched by sex, age, and educational levels. Depression and hopelessness were determined using Beckʹs depression inventory (BDI) and Beckʹs hopelessness (BHS) questionnaires. Using multiple linear regression models, the averages of BDI (t=2.637, P=0.009) and BHS (t=3.344, P=0.001) were significantly higher among the exposed subjects than among the control group. In Lali 57.8% and 14.1% of subjects had no depressed mood and moderate to severe depressed mood, respectively, while in MIS 31.3% and 35.9% of subjects had no depressed mood and moderate to severe depressed mood, respectively; the difference was significant (χ2=12.88, df=3, P=0.005). In Lali 35.9% and 12.5% of subjects had no hopelessness at all and moderate to severe hopelessness, respectively, while in MIS 17.2% and 32.8% of subjects had no hopelessness at all and moderate to severe hopelessness, respectively, the difference was significant (χ2=11.49, df=3, P=0.009). Replication is necessary and health implications are discussed.