The first, sickness (vyadhi), is a physical obstacle, but the other eight can be considered mental. These include languor (styana), doubt (samshaya), heedlessness (pramada), sloth (alasya), dissipation (avirati), false vision (bhranti-darshana), nonattainment of yogic states (alabdha-bhumikatva), and instability in these states (anavasthitatva).
The Yoga of Breath: A Step-by-Step Guide to Pranayama (ed. Shambhala Publications, 2002) - ISBN: 9780834825789