Friends:

 How do the 5 Mental Hindrances become 10?

The Blessed Buddha once explained:
How, Bhikkhus, do the five mental hindrances multiply into ten?                
Own internal sense-desire is a hindrance. Another's external sense-desire
is also a hindrance. Sense-desire is thus twofold: Internal and external!
Our own internal ill-will is a hindrance. Other's ill-will is a hindrance too...
Lethargy is a mental hindrance. Any laziness is also a mental hindrance.
Lethargy-and-laziness are therefore a dual mental hindrance.
Restlessness is a mental hindrance. Regrets & worries are also hindrances.
Therefore can restlessness-and-regret be explained as two hindrances.
Doubt and uncertainty about any internal condition, are a mental hindrance.
Doubt and uncertainty about any external phenomenon, are a hindrance too.
Thus does doubt-and-uncertainty become like a matched and mirrored pair...

Corresponding video: The 5 Mental Hindrances
https://www.youtube.com/watch?v=AF-m7FuFzII

Dhamma on Air #14 Audio: The 5 Hindrances
https://soundcloud.com/bhikkhu-samahita/dhamma-on-air-14-audio

More on  these 5 Mental Hindrances (Nīvaranas):
https://What-Buddha-Said.net/drops/II/The_5_Mental_Hindrances.htm
https://What-Buddha-Said.net/drops/II/Feeding_the_Hindrances.htm
https://What-Buddha-Said.net/drops/II/Starving_the_Hindrances.htm
https://What-Buddha-Said.net/drops/II/The_Canal.htm
https://What-Buddha-Said.net/drops/II/Naturally_Radiant.htm
https://What-Buddha-Said.net/drops/IV/Suitable_Substitution.htm
https://What-Buddha-Said.net/Canon/Sutta/AN/AN.I.3-4.htm
https://What-Buddha-Said.net/Canon/Sutta/AN/AN.I.3-4c.htm
https://What-Buddha-Said.net/drops/II/The_Fire_of_Sense-Desire.htm
https://What-Buddha-Said.net/drops/II/Colourful_but_Muddy.htm
https://What-Buddha-Said.net/drops/II/Anger_and_Irritation.htm
https://What-Buddha-Said.net/drops/II/Lethargy_and_Laziness.htm
https://What-Buddha-Said.net/drops/II/Restlessness_and_Regret.htm
https://What-Buddha-Said.net/drops/II/Doubt_and_Uncertainty.htm

Source (edited extract):
The Grouped Sayings of the Buddha. Samyutta Nikāya.
Book [V:110] section 46: The Links. 52: The Explanation...

The 5 mental Hindrances!