SEOUL, April 22 (Yonhap) — Employees at small and medium-sized enterprises (SMEs) are more vulnerable to depression and stress caused by the coronavirus pandemic, also dubbed the “corona blues,” than their counterparts at large companies, a state agency said Thursday.

The Korea Workers’ Compensation and Welfare Service affiliated with the labor ministry came to the conclusion after analyzing scales of perceived stress and sleep disturbance among workers at both small and large businesses amid the spread of COVID-19 last year.

The perceived stress scale (PSS), a classic stress assessment instrument, for 184 workers at seven SMEs each with fewer than 300 employees, who participated in the agency’s stress management program, averaged 19.65 points, higher than 14.62 points tallied for all 7,880 corporate workers polled by the agency, including those at conglomerates.

The so-called sleep disturbance scale (SDS) for SME employees was 6.09 points, higher than 4.82 points for all corporate workers, the agency said. The normal ranges of the PSS and the SDS are 14 to 23 and 8 to 14, respectively.

The stress and sleep disturbance indices for SME workers are not at abnormal or dangerous levels, but they may feel more stressed and suffer from more severe sleep disturbance than their counterparts at large companies, the agency explained.

The agency cited COVID-19-related employment anxiety, fears of income reduction and inability to work from home among the apparent stressors for SME employees.

It then noted that the PSS and SDS for SME workers slightly improved to 18.7 points and 5.74 points, respectively, after they finished its stress management programs.