Exposure to toxic chemicals appears to be one of the major factors in the onset of Schizophrenia. Present study was designed to find out the association of socio-economic, clinical and heavy metals such as chromium (Cr), lead (Pb) copper (Cu), zinc (Zn), iron (Fe), manganese (Mn) selenium (Se) and arsenic (As) as the principle environmental factors that appear to impact schizophrenic condition in Pakistani population. In this study we have tried to expose some factors such as drug abuse, marital status, education, monthly income that could be related to the disease. These parameters were not investigated before in Pakistani subjects. A self-made questionnaire was developed to collect and record the history of patient’s social and economical status. The level of transition metals in the whole blood was also measured by using Inductive couple plasma optical emission spectroscopy (ICP-OES). Present study has found higher levels of Cr, Pb, Zn, Se, As and Cu and lower levels of Fe and Mn in the blood of newly diagnosed (ND) patients when compared to the controls. While comparing ND with the patients who were on medication (Old Diagnosed) we, found lower level of these metals except for copper in ND. However no significant differences were observed between any trace metal levels between the studied groups. The survey concludes that economic status, marital status and illegal drugs are significantly associated with schizophrenia. Pakistani men who use cannabis are significantly higher in numbers when compared to women in acquiring the psychiatric symptoms.
Schizophrenia is a Greek Word meaning split mind. It is a psychiatric diagnosis that describes a mental disorder characterized by impaired judgment, behavior and an inability to interpret reality. It affects approximately 1% of the total world population where as in Pakistan 1.5% of population is enduring from this ailment [
Recent research established an association between DNA methylation and environmental metals [
Appropriate questionnaire was developed as to obtain personal information and to identify factors responsible for the onset of Schizophrenia. All patients selected for sampling were first asked to read and understand the consent form with the help of their attendant and sign before taking the samples. Total diagnosed Schizophrenic subjects were 35 with the age range between 15 - 50 years for males and 12 - 59 years for females with 20 siblings as controls. All the subjects were Pakistanis. Schizophrenic patients were divided into two groups. First group contain 23 patients who were on antipsychotic drugs (old diagnosed) and second group contain 12 newly diagnosed (ND) patients. The ND patients are also schizophrenics but they were being just diagnosed and were not on medication. However they were addicted to drugs such as cannabis, tobacco, hashish, alcohol and betel nut. The study was approved by the Human Ethics Committee of Jinnah postgraduate medical center (JPMC), Karachi, Pakistan with the ethic number of F.2-81/2008-GENL/2128/JPMC.
Appropriate self made questionnaire was developed as to obtain personal information and to identify many socio-economic factors that could be responsible for the onset of schizophrenia. All patients were clinically evaluated by expert psychiatrists by taking the history and clinical examinations. Patients self assessment survey was done by government hospitals and some private hospitals situated in Karachi, Pakistan.
Blood samples were collected from Schizophrenic patients and their control (sibling). These patients were diagnosed according to the DSM-IV and ICD-10 criteria and were admitted to the psychiatric wards of Jinnah postgraduate medical center and Civil Government Hospital, Karachi, Pakistan. 5 ml blood samples were collected from each subject (patients and controls) into metal free plastic tubes containing heparin.
For digestion of biological samples of patients and controlled subjects of human whole blood were directly taken into Pyrex flasks separately, added 5 ml whole blood was mixed into digestion acid of a freshly prepared mixture of concentrated HNO3-H2O2 (2:1, v/v) digested at 60˚C - 70˚C for 1 - 2 h. The digests were then treated with 2 ml nitric acid and few drops of H2O2, heated on hot plate about 80˚C until the clear digested solution was obtained, the excess acid mixture was evaporated to semidried mass, cooled and diluted with 0.1 mol/l nitric acid. Once the beaker was cooled then the content was diluted with de-ionized water up to 50 ml volume.
It is a very sensitive technique of mass spectrometry which is capable of detecting metals and several non-metals at concentrations as low as one part in 106 (part per million) (
Standard solutions of heavy metals were provided by Merck (Darmstadt, Germany). The standards were prepared from the individual 1000 mg/l standards (Merck), in 0.1M HNO3. Working standards were prepared from the stock solutions. Quality assurance (QA) and quality control (QC) procedures were strictly followed through- out the present study. The level of accuracy and QC for the determination of heavy metal concentrations was comprised of measurements of natural matrix Certified Reference Material (CRM) and the measurements of duplicates for each batch of samples. NIST standard 1573 was used for the evaluation of procedures. Reproducibility of the measurements for the metals ranged between 92.3 and 113 percentage relative standard deviation (%RSDs). RSD is generally better than 5% if an analyte concentration is about 10 times higher than the relevant limit of detection. The mean recovery for certified reference material (CRM 1573) was below 8.7% whereas the percent recovery of RSD for duplicate samples were less than 9%. Student’s t-test and chi square was carried out for statistical analysis with the program SPSS version 17 for windows (
ICP-MS parameters | |||||
---|---|---|---|---|---|
Analysis lines | |||||
Elements | Wavelength | Types | PPP | Atomic weight | |
Cu | 324.754 | Analyte | 2 | 63.54 | |
Mn | 257.610 | Analyte | 2 | 54.94 | |
Pb | 220.353 | Analyte | 2 | 207.19 | |
Zn | 206.200 | Analyte | 2 | 65.57 | |
Fe | 238.204 | Analyte | 2 | 55.85 | |
Cr | 267.716 | Analyte | 2 | 52.00 | |
Se | 196.09 | Analyte | 2 | 78.96 | |
As | 189.04 | Analyte | 2 | 74.92 | |
Conditions set | |||||
Power (Kw) | 1.20 | ||||
Plas flow (L/min) | 15.0 | ||||
Aux flow (L/min) | 1.50 | ||||
Neb flow (L/min) | 0.75 | ||||
Replicate times (s) | 5.000 | ||||
Stab range (s) | 10 | ||||
Sample uptake (s) | 7 | ||||
Rinse time (s) | 10 | ||||
Pump rate (rpm) | 30 | ||||
Fast pump | On | ||||
Calibration setting | |||||
Calibration Mode | Quantitative | ||||
No. Standard | 5 | ||||
Corr Coeff Limit | 0.995000 | ||||
Standard concentration for each metal | |||||
Standard 1 | 0.01000 | ||||
Standard 2 | 0.10000 | ||||
Standard 3 | 1.00000 | ||||
Standard 4 | 10.0000 | ||||
Standard 5 | 50.0000 | ||||
SPSS software version 17 was used for the analysis of the data. The results were expressed as Means ± SD by using SPSS software. Students paired t test were performed for the determination of difference between group means. The significance level was set as p < 0.05. Chi square was also carried out to determine the association of socio-economic factors such as marital status, education, age, and residential area to the levels of trace metals in Schizophrenic patients.
According to our questionnaire all participants were living in the nearby vicinity of the same city i.e. Karachi, though they were from different ethnic background. The socio-demographic and clinical characteristics were compared between schizophrenic male and female patients (
Variables | Males (n = 60) | Females (n = 80) | df | t value | P values |
---|---|---|---|---|---|
Age | 15 - 50 years | 12 - 59 years | |||
Age at onset | |||||
Mean ± SD | 25.09 ± 7.11 | 23.9 ± 8.64 | 137 | 0.85 | NS |
Age at contact | |||||
Mean ± SD | 29.1 ± 8.7 | 27.43 ± 10.33 | 138 | 1.01 | NS |
Variables | Males (n = 60) | Females (n = 80) | df | X2 value | P values |
Marital status | |||||
Single Married Divorced Widow | 53.3% (32) 45% (27) 1.6% (1) No | 33.75% (27) 51.25% (41) 13.75% (11) 1.25% (1) | 3 | 9.98 | **0.01 |
Education | |||||
Nil School Grade ( 5-10) College (11-14) University | 20% (12) 63.33% (38) 16.66% (10) 0% | 25% (20) 58.75% (47) 13.75% (11) 2.5% (2) | 3 | 2.18 | NS |
Salary bracket | |||||
Lower Middle Upper | 53.3% (32) 46.66% (28) 0% | 43.75% (35) 45% (36) 11.25% (9) | 2 | 7.42 | *0.02 |
Symptoms | |||||
Negative Positive | 78% (47) 21.6% (13) | 63.75% (51) 36.25% (29) | 1 | 3.47 | NS |
Drug abuse | |||||
Cannabis Tobacco Charas Alcohol Betel Nut | 16.6% (10) 36.66% (22) 15% (9) 13.33% (8) 10% (6) | 2.5% (2) 18.75% (15) 2.5% (2) 13.75% (11) 25% (20) | 5 | 34.83 | ***0.00000162 |
Our data shows no significant difference in the onset of disease between the genders and the mean age of the groups i.e. from 12 - 59 years. There were no significant differences found to be present between the ages of onset and contact among the groups. This shows that males and females are equally prone to have schizophrenia. Moreover men and women of ages between 12 - 59 years were equally susceptible and can develop schizophrenic symptoms. Interestingly there was a slight non-significant difference (x2 = 3.472, p = 0.06) found between positive and negative symptoms only in between the genders. It was found that 78% of men shows a negative and 36.25% women shows positive symptoms of schizophrenia (
According to our survey all Pakistani Schizophrenic subjects have completed their primary or secondary education except for 2.5% of the effected population that has reached up to the university level. In Pakistani population we have observed that single men and married or divorced women have significantly higher tendency to develop schizophrenia (
Trace elements are directly involved in human metabolism and there is a growing interest in the role of certain elements in physiological and psychological processes. The level of trace metals such as Cr, Pb, Zn, Cu, Fe, Se, As and Mn have been detected in ppm (mg/L) in blood samples of Pakistani Schizophrenic patients (
When we compared individual values of trace metals in male and female Schizophrenic patients, we found higher values of Cr, Pb, Fe and Mn in males while Zn and Cu in females (
Patients | Cr (ppm) | Pb (ppm) | Zn (ppm) | Cu ((ppm) | Fe (ppm) | Mn (ppm) | Se (ppm) | As (ppm) |
---|---|---|---|---|---|---|---|---|
Newly Diagnosed (n = 12) | ||||||||
Mean ± SD | 0.98 ± 1.25 | 1.80 ± 2.90 | 10.80 ± 3.83 | 5.99 ± 5.38 | 360.97 ± 74.60 | 0.21 ± 0.18 | 0.56 ± 0.29 | 0.23 ± 0.19 |
Old Diagnosed (n = 22) | ||||||||
Mean ± SD | 0.51 ± 0.30 | 0.75 ± 0.37 | 10.73 ± 4.52 | 7.21 ± 7.36 | 353.19 ± 133.47 | 0.14 ± 0.06 | 0.49 ± 0.22 | 0.24 ± 0.21 |
Control (n = 19) | ||||||||
Mean ± SD | 0.70 ± 0.45 | 0.70 ± 0.40 | 9.69 ± 3.45 | 4.36 ± 5.20 | 393.08 ± 102.76 | 0.17 ± 0.12 | 0.49 ± 0.22 | 0.2 ± 0.19 |
at-value p-value | 0.913 0.369 | 1.643 0.111 | 0.837 0.409 | 0.836 0.410 | 0.935 0.358 | 0.721 0.477 | 0.69 0.49 | 0.21 0.83 |
bt-value p-value | 1.584 0.121 | 0.409 0.685 | 0.818 0.418 | 1.410 0.167 | 1.059 0.296 | 1.143 0.260 | 0.83 0.41 | 0.47 0.63 |
ct-value p-value | 1.702 0.089 | 1.693 0.10 | 0.045 0.964 | 0.506 0.617 | 0.186 0.854 | 1.713 0.96 | 1.36 0.18 | 0.16 0.86 |
Clearly demonstrates that the levels of trace metals were not significantly different in both groups of schizophrenic patients when compared with the controls. aControl when compared to newly diagnosed , bControl when compared to old diagnosed, cNewly diagnosed when compared to old diagnosed, SD = Standard Deviation, n = number of patients, Ppm = part per million.
Females Patients | Cr (ppm) | Pb (ppm) | Zn (ppm) | Cu (ppm) | Fe (ppm) | Mn (ppm) | Se (ppm) | As (ppm) |
---|---|---|---|---|---|---|---|---|
Control (n = 6) | ||||||||
Mean ± SD | 0.69 ± 0.27 | 0.81 ± 0.36 | 11.3 ± 5.36 | 6.38 ± 7.89 | 431.45 ± 102.24 | 0.11 ± 0.01 | 0.49 ± 0.25 | 0.25 ± 0.27 |
Minimum | 0.22 | 0.47 | 7.09 | 0.93 | 292.89 | 0.10 | 0.12 | 0.01 |
Maximum | 1.26 | 1.32 | 21.77 | 18.64 | 554.70 | 0.14 | 0.81 | 0.78 |
Newly Diagnosed (n = 3) | ||||||||
Mean ± SD | 0.49 ± 0.11 | 1.128 ± 0.46 | 13.88 ± 5.52 | 9.89 ± 6.42 | 321.09 ± 110.66 | 0.11 ± 0.01 | 0.52 ± 0.25 | 0.11 ± 0.06 |
Minimum | 0.39 | 0.79 | 8.55 | 2.53 | 209.03 | 0.10 | 0.37 | 0.13 |
Maximum | 0.62 | 1.66 | 19.57 | 14.31 | 430.30 | 0.55 | 0.82 | 0.34 |
Old Diagnosed (n = 10) | ||||||||
Mean ± S.D | 0.53 ± 0.32 | 0.71 ± 0.27 | 10.49 ± 3.57 | 7.17 ± 6.04 | 343.15 ± 162.36 | 0.14 ± 0.05 | 0.47 ± 0.23 | 0.24 ± 0.15 |
Minimum | 0.22 | 0.24 | 5.88 | 0.94 | 95.48 | 0.08 | 0.18 | 0.05 |
Maximum | 1.29 | 1.24 | 19.00 | 19.36 | 608.65 | 0.22 | 0.76 | 0.61 |
Data compared individual values of trace metals in female and found higher values of Zn, and Cu in female patients. SD = Standard Deviation, n = number of patients, ppm = part per million.
(b)
Data showing the comparison of individual values of trace metals levels in male patients among three groups. We found higher values of Cr, Pb, and Mn in male patients. SD = Standard Deviation, n = number of patients, ppm = part per million.
In Pakistan 1.5% of the population is suffering from Schizophrenia and its prevalence is higher because of the poor care and un-acceptance of disorder. Their families believed in Shamans (Aamil/Peer) for the treatment which usually makes their conditions worse. Major factors like unemployment, living standard, education, marital status, economic status and cost of treatment play significant roles for the onset of schizophrenia in Pakistan. In this study we identified factors such as drug abuse, marital status, education, monthly income that are related with Schizophrenia. Likewise the levels of trace metals observed in the controls and patients were directing some clues for the disease.
According to our survey females are more affected than men (
We observed that patients were addicted to tobacco, cannabis, betel nut, and charas. We found that high percentages of males (16.6%) were using cannabis than tobacco and alcohol and cannabis increases the levels of dopamine in the brain, which can lead to Schizophrenic symptoms [
There is increasing evidence suggesting that the transition metals are essential for many metabolic processes and their homeostasis is crucial for life [
Caution should be taken even the levels of Cr, Zn, Mn and Pb is non-significantly elevated and may make the patients vulnerable to acquire more psychotic symptoms. Importantly it was reported [
We would like to acknowledge the financial support from Higher Education Commission (HEC) Islamabad project number 1028, and recurrent grant from PCMD University of Karachi, during this research. We would also like to thanks to the specialist Mr. Felix from The Central Laboratories Unit, Research Affairs, UAE University, for analyzing great number of samples using ICP-OES.