The relevant paragraph is in Section 2.2.5:

OCD is ranked by the WHO in the top ten of the most disabling illnesses by lost income and decreased quality of life (Bobes et al., 2001). The severity of OCD differs markedly from one person to another. While some people may be able to hide their OCD from their own family, the disorder may have a major negative impact on social relationships leading to frequent family and marital discord or dissatisfaction, separation or divorce (Koran, 2000). It also interferes with leisure activities (Antony et al., 1998) and with a person’s ability to study or work, leading to diminished educational and/or occupational attainment and unemployment (Koran, 2000; Leon et al., 1995). The social cost (that is the person’s inability to fully function in society) has been estimated as US$5.9 billion in 1990, or 70.4% of the total economic cost of OCD (DuPont et al., 1995).

Following the Bobes et al. citation yields:

Obsessive-compulsive disorder is the fourth most common psychiatric disorder, occurring in 2–3% of the U.S. population [14]. Furthermore, OCD is a chronic and disabling illness that impacts negatively on the academic, occupational, social, and family function of patients [11, 12, 17]. This impact carries over onto their families, friends, and society [12]. Indeed, OCD ranks tenth in the World Bank’s and WHO’s ten leading causes of disability and, in the case of women aged 15–44 years, OCD occupies the fifth position [22]. In spite of this situation, to our knowledge data on quality of life and disability has scarcely been reported in OCD patients.

Reference 22 is to "WHO Fact Sheet no. 217", which no longer exists. Luckily, the Wayback Machine has a copy. The relevant point:

It is also of great significance that 5 of the 10 leading causes of disability worldwide (major depression, schizophrenia, bipolar disorders, alcohol use, obsessive compulsive disorders) are mental problems. They are as relevant in developing countries as they are in industrialised societies

Unfortunately, there is no citation and it does not precisely match Bobes et al's claims. Neither Bobes et al. nor the WHO fact sheet refers to lost income, so the reference to that in the original claim is wholly unsubstantiated by these citations.