Psychopath Diary

Psychopath Diary (Korean싸이코패스 다이어리) is a 2019 South Korean television series starring Yoon Shi-yoon, Jung In-sun and Park Sung-hoon. It aired on tvN from November 20, 2019 to January 9, 2020.

Psychopath Diary
Psychopath Diary Poster.jpeg
Promotional poster
싸이코패스 다이어리
Revised RomanizationSsaikopaeseu Daieori
Created byStudio Dragon
Written by
  • Choe Sung-jun
  • Kim Hwan-chae
  • Ryu Yong-jae
Directed byLee Jong-jae
Country of originSouth Korea
Original languageKorean
No. of episodes16
Running time60 minutes[2]
Production companyKeyEast[3]
Original networktvN
Picture format1080i (HDTV)
Audio formatDolby Digital
Original releaseNovember 20, 2019 (2019-11-20) –
January 9, 2020 (2020-01-09)


Yook Dong-sik (Yoon Shi-yoon), an analyst who works at Daehan Securities, has a timid personality and he can't even get angry at the people who look down upon him. One day, shortly after failing on his attempt of suicide, he witnesses a murder. He unintentionally picks up a diary belonging to murderer, on which was written the log of his murders. He flees with the diary, but he is accidentally hit by Police Officer Shim Bo-kyung's (Jung In-sun) patrol car which causes him to suffer from retrograde amnesia. Due to the diary in his possession, Dong-sik mistakenly believes he is a psychopath. Since that moment, his behavior started to change. Bo-kyung, who got involved with Dong-sik, decides to catch the serial killer.

Meanwhile, Seo In-woo (Park Sung-hoon), the director and son of the chairman of Daehan Securities where Dong-sik works, turns out to be the heartless psychopath serial killer. He loses his diary when his 6th victim, a homeless old man tossed his diary away. He feels insecure ever since.[4]



  • Yoon Shi-yoon as Yook Dong-sik, a timid and pushover man who works as a clerk at Daehan Securities. His weak personality begins to change when he perceive himself as a killer.[5]
  • Jung In-sun as Shim Bo-kyung, an officer in a patrol station.[6]
  • Park Sung-hoon as Seo In-woo, the real psychopathic serial killer who is also the director of Daehan Securities where Dong-sik works at.[5]


People around Yook Dong-sikEdit

  • Lee Han-wi as Yook Jong-chul, Dong-sik's father.
  • Hwang Geum-byul as Yook Ji-yeon, Dong-sik's older sister.
  • Kim Gyul as Jo Yong-gu, Dong-sik's brother-in-law.[7]
  • Jung Su-bin as Yook Dong-chan, Dong-sik's younger half-brother.[8]
  • So Hee-jung as Na In-hye, Dong-sik's step-mother, Dong-chan's mother.
  • Heo Sung-tae as Jang Chil-sung, a gangster who lives at Unit 708. He later addresses Dong-sik as his 'Big Boss' after mistakenly believes him to be a serial killer.

People around Shim Bo-kyungEdit

  • Choi Sung-won as Heo Taek-soo, Bo-kyung partner.
  • Kim Myung-soo as Shim Seok-gu, Bo-kyung's father who is a former investigator police.
  • Lee Kan-hee as Lee Suk-yeon, Bo-kyung's mother.
  • Lee Hae-young as Officer Ryu Jae-joon

People around Seo In-wooEdit

  • Park Jung-hak as Seo Chung-hyeon, In-woo's father who is the chairman of Daehan Securities.
  • Yoo Bi as Seo Ji-hun, In-woo's step-brother and managing director of Daehan Securities.
  • Yoon Ye-hee as Kim Eun-shil, Chung-hyeon's wife and Ji-hun's mother.
  • Kim Hye-na as Seo Ji-eun, In-woo's step-sister.
  • Lim Il-gyu as Kim Chan-il, In-woo's brother-in-law.
  • Han Soo-hyun as Kim Mu-seok, former detective who now works for In-woo.

People at Daehan SecuritiesEdit

  • Choi Dae-chul as Gong Chan-seok, the manager of Team 3 and Dong-sik's boss who is selfish and rude.
  • Kim Ki-doo as Park Jae-ho, Dong-shik's cunning team member who claims to be his best friend.
  • Jo Shi-nae as Han Jung-ah, Dong-sik's colleague.
  • Lee Min-ji as Oh Min-joo
  • Choi Tae-hwan as Shin Seok-hyun[9]
  • Hwang Sun-hee as Jo Yoo-jin[9]


  • Gu Ja-geon as a bully

Special appearancesEdit

  • Jung Hae-kyun as Kim Myung-gook, a homeless man. (Ep. 1–2)
  • Yura as a girl with a dog in park (Ep. 2)
  • Nam Jung-hee as murder victim (Ep. 2)
  • Jo Yoon Ho as Chil-sung's junior (Ep. 2)
  • Han Ji-eun as a woman with a big guy (Ep. 2)
  • Yoon Ji-on as Joo Young-min (Ep. 4–5)
  • Lee Hyun-woong as Oh Myung-dal (Ep. 12–13, 16)


The first script reading was held in August 2019 in Sangam-dong, Seoul.[10]

Original soundtrackEdit

Psychopath Diary OST
Soundtrack album by
Various Artists
LabelStone Music Entertainment

Part 1Edit

Released on December 12, 2019 (2019-12-12)
1."Wanna be Bad" (슬퍼하고싶어)Woosung (The Rose)2:59
2."Wanna be Bad" (Inst.) 2:59
Total length:5:18

Part 2Edit

Released on January 2, 2020 (2020-01-02)
1."Stay the same" (동일하게)Cha Yeo-wool3:26
2."Stay the same" (Inst.) 3:26
Total length:6:52
Disc 2:
1."Psychopath Diary" (Opening Title)Um Ki Yup, Um Ki Hyun, Lee Sun Gyeol2:54
2."Dongshik's Polka"Um Ki Yup, Um Ki Hyun, Lee Sun Gyeol2:35
3."Red Diary"Um Ki Yup, Park Min Ji2:40
4."Suspense"Kim Hee Jin1:40
5."Dongshik's related memories"Um Ki Yup, Um Ki Hyun, Park Min Ji3:46
6."Do I look like a pushover"Um Ki Yup, Um Ki Hyun3:10
7."I'm a Psycho"FaraEffect3:06
Total length:24:17


Psychopath Diary : South Korea viewers per episode (thousands)
SeasonEpisode numberAverage
Source: Audience measurement performed nationwide by Nielsen Korea.[11]
Average TV viewership ratings
Ep. Original broadcast date Average audience share
(Nielsen Korea)[12]
Nationwide Seoul
1 November 20, 2019 1.766% 1.730%
2 November 21, 2019 1.463% 1.361%
3 November 27, 2019 1.928% 2.057%
4 November 28, 2019 2.206% 2.174%
5 December 4, 2019 2.368% 2.507%
6 December 5, 2019 2.212% 2.346%
7 December 11, 2019 2.424% 2.866%
8 December 12, 2019 2.299% 2.782%
9 December 18, 2019 2.014% 2.099%
10 December 19, 2019 1.693% 1.954%
11 December 25, 2019 1.708% 2.025%
12 December 26, 2019 2.295% 2.718%
13 January 1, 2020 1.939% 2.213%
14 January 2, 2020 2.423% 2.633%
15 January 8, 2020 2.685% 2.762%
16 January 9, 2020 2.983% 3.372%
Average 2.150% 2.350%
  • In the table above, the blue numbers represent the lowest ratings and the red numbers represent the highest ratings.
  • This series aired on a cable channel/pay TV which normally has a relatively smaller audience compared to free-to-air TV/public broadcasters (KBS, SBS, MBC and EBS).


  1. ^ "윤시윤·정인선·박성훈, 코믹 스릴러 '싸이코패스 다이어리' 주연 확정". Naver (in Korean). Digital Times. Retrieved September 7, 2019.
  2. ^ "Psychopath Diary (2019)". CJ ENM. Archived from the original on March 26, 2022. Retrieved March 26, 2022.
  3. ^ "'싸이코패스 다이어리' 이한위 허성태→이민지까지, 퍼펙트 라인업(공식)". Naver (in Korean). Newsen. Retrieved September 7, 2019.
  4. ^ "'싸이코패스 다이어리' 윤시윤X정인선X박성훈, 캐스팅 확정…믿보 라인업 구축". Naver (in Korean). Hankyung. Retrieved September 7, 2019.
  5. ^ a b "Yoon Si-yoon, Jung In-sun, Park Sung-hoon Confirmed for "Psychopath Diary"". HanCinema. News1 Korea. Retrieved September 7, 2019.
  6. ^ "Yoon Si-yoon and Jung in-sun Courted for Drama "Psychopath Diary"". HanCinema. Xports News. Retrieved September 7, 2019.
  7. ^ "Kim Gyul to Star in "Psychopath Diary"". HanCinema. Wow TV. Retrieved September 7, 2019.
  8. ^ "빅톤 정수빈, tvN '싸이코패스 다이어리' 합류…연기돌 행보(공식)". Naver (in Korean). Newsen. Retrieved September 24, 2019.
  9. ^ a b "Hwang Sun-hee and Choi Tae-hwan Confirmed for "Psychopath Diary"". HanCinema. Retrieved September 7, 2019.
  10. ^ "'싸이코패스 다이어리' 윤시윤·정인선·박성훈, 첫 리딩부터 '시너지↑'". Naver (in Korean). Ilgan Sports. Retrieved September 26, 2019.
  11. ^ "Nielsen Korea". AGB Nielsen Media Research (in Korean). Retrieved July 29, 2020.
  12. ^ "Nielsen Korea". AGB Nielsen Media Research (in Korean). Archived from the original on June 1, 2016. Retrieved November 20, 2019.

External linksEdit