The Impact of Treatments for Depression on the Dynamic Network Structure of Mental States: Two Randomized Controlled Trials

Abstract

Evidence is growing that vulnerability to depression may be characterized by strong negative feedback loops between mental states. It is unknown whether such dynamics between mental states can be altered by treatment. This study examined whether treatment with imipramine or treatment with Mindfulness-Based Cognitive Therapy (MBCT) reduces the connectivity within dynamic networks of mental states in individuals with depressive symptoms. In the Imipramine trial, individuals diagnosed with major depression were randomized to imipramine treatment or placebo-pill treatment (n = 50). In the Mind-Maastricht trial, individuals with residual depressive symptoms were randomized to Mindfulness-Based Cognitive Therapy (MBCT) or to a waiting-list control condition (n = 119). Lagged associations among mental states, as assessed with the Experience Sampling Method (ESM), were estimated at baseline and post-intervention. The results show that few of the dynamic network connections changed significantly over time and few of the changes after MBCT and imipramine treatment differed significantly from the control groups. The decrease in average node connectivity after MBCT did not differ from the decrease observed in the waiting-list control group. Our findings suggest that imipramine treatment and MBCT do not greatly change the dynamic network structure of mental states, even though they do reduce depressive symptomatology.

Figure 1. Flow chart of participants of the Imipramine trial included in the current study.

Figure 2. Flow chart of participants of the Mind-Maastricht trial included in the current study.

Figure 3. Networks of momentary mental states in the Imipramine Trial.

Note. Networks of momentary mental states in the Imipramine Trial. wor = worried, dow = down, che = cheerful, agi = agitated, ins = insecure. The arrows represent the significant lagged associations between the mental states. Solid arrows reflect positive associations and dashed arrows reflect negative associations. The thickness of the lines reflect the strength of the associations; the thicker the line, the stronger the association.

Figure 4. Networks of momentary mental states in the Mind-Maastricht Trial.

Note. wor = worried, dow = down, che = cheerful, agi = agitated, ins = insecure. The arrows represent the significant lagged associations between the mental states. Solid arrows reflect positive associations and dashed arrows reflect negative associations. The thickness of the lines reflect the strength of the associations; the thicker the line, the stronger the association.