Problem-solving therapy is quite effective for treating depression, remarkably mild to moderately depressed individuals.

• Meta-analyses (studies of studies) consistently find that PST extensively lowers depressive symptoms compared to no treatment or placebo.

• For example, Bell and D’Zurilla (2009) reviewed multiple trials and found that PST had a moderate to large effect size (Cohen’s d = 0.54–0.84) in reducing depression.

(In research, a Cohen’s d of 0.5 is considered moderate; 0.8 is large — so that’s a solid effect.)

• In a randomized controlled trial, Areán and colleagues (2010) compared PST to antidepressant medication (citalopram) in older adults with major depression.

• PST was just as helpful as medication in reducing depressive symptoms after 12 weeks.

• Another study by Alexopoulos et al. (2011) discovered that PST diminished depression and improved executive function in elderly patients with cognitive impairment, meaning it helps even when depression is complicated by memory and thinking problems.

How does PST’s effectiveness compare to other therapies?

• PST vs. cognitive behavioral therapy (CBT)

CBT is still considered the “gold standard” for depression, but PST performs similarly to CBT in many studies, especially when it comes to treating people with fewer resources, chronic illness, or who need short-term interventions.

• PST vs. medication

As mentioned above, PST can be equally effective as antidepressants for many people with mild-to-moderate depression, without the side effects.

• PST combined with other treatments

PST is often used with medication or other therapies to boost effectiveness in more severe or treatment-resistant cases.