Contents of the first session include:

1. Adherence behavioral skills. Identify barriers to optimal HAART adherence. Know behavioral skills that can deal with these barriers, such as forgetting, afraid of others' questioning and side effects.
2. Adherence information and motivation. Know how the HIV virus attack human body and the mechanisms of HAART medication. Understand the influence of adherence level on health outcomes.

Contents of the second session include:

1. Adherence motivation. Discuss possibilities and hope of future life, intimate relationship and career.
2. Mother-child interaction skills. Identify speaking styles that have a negative influence on mother-child interactions concerning HAART medication. Learn effective communication skills.
3. Acquiring social support. Know people and resources that could provide support when having HAART-related difficulties and problems.

Perceived stigma will be assessed by the 8-item HIV Stigma Scale (Berger et al., 2001; Li et al., 2016). Possible scores range from 8 to 32, with a higher score indicating a higher level of perceived stigma.

Emotional regulation will be assessed by the Emotional Management Strategy Questionnaire (Fabrizio et al., 2015). Possible scores range from 10 (worst emotional regulation) to 60 (best emotional regulation).

Positive coping will be assessed by a combination of the positive reappraisal subscale from the Cognitive Emotion Regulation Questionnaire (Garnefski et al., 2002; Zhu et al., 2008) and the Emotional Processing Subscale from the Emotional Approach Coping Scales (Stanon et al., 2000; Tse et al., 2020). Possible scores range from 8 to 40, with a higher score indicating better positive coping.

Social support will be assessed by a combination of the Perceived Social Support Scale (Blumenthal et al., 1987; Huang, Jiang, & Ren, 1996), the possible scores of which range from 0 (lowest level of support) to 72 (highest level of support), and the usage of support subscale of the Social Support Assessment Scale (Xiao & Yang, 1987), the possible scores of which range from 3 (lowest level of support utilization) to 12 (highest level of support utilization)

Self-efficacy will be assessed by the General Self-Efficacy Scale (Schwarzer & Aristi, 1997). Possible scores range from 10 to 40, with a higher score indicating a higher level of efficacy.

Adherence information, motivation, and behavioral skills will be assessed by the LifeWindows Information-Motivation-Behavioral Skills Antiretroviral Therapy Adherence Questionnaire (LifeWindows Project Team, 2006; Peng et al., 2020). Possible scores of the information, motivation, and behavioral skills subscale range from 9 to 45, 8 to 40, and 13 to 65, respectively, with a higher score indicating a higher level of information, motivation, and behavioral skills.

Illness perception will be assessed by the Brief Illness Perception Questionnaire (Broadbent et al., 2006). Possible scores of each of the eight items range from 0 to 10, and each item will be used separately.

Adherence efficacy will be assessed by the HIV Treatment Adherence Self-Efficacy Scale (Johnson et al., 2007; Sun et al., 2016). Possible scores range from 0 to 120, with a higher score indicating a higher level of perceived efficacy.

Children's medication-taking responsibility perception and allocation (between mother and child) will be assessed by two visual analog scales respectively. Possible scores of each item range from 0 to 10, with a higher score indicating more self-responsibility than mother-responsibility.

Mother-child closeness will be assessed by the Closeness subscale of the Network of Relationships-Relationship Quality Version (Buhrmester & Furman, 2008; Kong et al., 2012), the possible scores of which range from 15 (lowest level of closeness) to 90 (highest level of closeness) and the Inclusion of Other in the Self Scale (Aron, A., Aron, N., & Smollan, 1992), the possible scores of which range from 1 (lowest level of closeness) to 7 (highest level of closeness).

Family harmony will be assessed by the Family Harmony Scale (Kavikondala et al., 2016). Possible scores range from 10 to 60, with a higher score indicating a higher level of harmony.

Mother-child conflict will be measured by the frequency and intensity of parent-child conflicts (Yau & Smetana, 1996), the possible scores of which range from 2 (no conflict) to 10 (highest level of conflict).

Relationship satisfaction will be assessed by a single-item relationship ladder. Possible scores range from 0 to 10, with a higher score indicating a higher level of satisfaction.