Patterns of utilization of antipsychotic drugs and direct medical costs among patients with schizophrenia in a tertiary care hospital

Table 3 History of duration of illness distribution and substance abuse of study population

History of illness (in months)	Number of patients (n = 159)	Mean years of history of illness for subcategories	SD
< 6 months	40	3.49	1.77
6-12 months	42	11.05	1.71
13-24 months	77	21.74	2.93
0-24 months	159	14.32	8.06
Substance abuse in study population
Characteristic	Alcohol use	Tobacco use	Cannabis use
Yes (present)	20	35	15
No (absent)	139	124	144
Total	159	159	159