Persons with ID and staff who are involved in BLT. Either by receiving BLT, or by prescribing or facitating BLT.

for 2 weeks the patient will take place for a 10.000lux lamp for 20-30 minutes.

Acceptability (Proctor et al., 2011) is the perception among implementation stakeholders that a given treatment, service, practice, or innovation is agreeable, palatable, or satisfactory. This will be measured by interviews.

Appropriateness (Proctor et al., 2011) is the perceived fit, relevance, or compatibility of the innovation or evidence based practice for a given practice setting, provider, or consumer; and/or perceived fit of the innovation to address a particular issue or problem. This will be measured by interviews.

Feasibility (Proctor et al., 2011) is defined as the extent to which a new treatment, or an innovation, can be successfully used or carried out within a given agency or setting. This will be measured by interviews.

Fidelity (Proctor et al., 2011) is defined as the degree to which an intervention was implemented as it was prescribed in the original protocol or as it was intended by the program developers. This will be measured by interviews and by case report study.

Implementation strategies are methods to enhance the adoption, implementation and sustainability of a policy or intervention. This will be studied with interview data and logs.

Depressive symptoms measured by the Anxiety, Depression, and Mood Scale (ADAMS, Hermans et al., 2008). It contains 28 items, each can be scored 0 to 3. Minimum score 0 and maximum score 84 and higher scores mean worse outcome.